Submitted Successfully!
To reward your contribution, here is a gift for you: A free trial for our video production service.
Thank you for your contribution! You can also upload a video entry or images related to this topic.
Version Summary Created by Modification Content Size Created at Operation
1 + 4229 word(s) 4229 2021-02-23 02:54:55 |
2 format correct Meta information modification 4229 2021-03-18 03:48:37 |

Video Upload Options

We provide professional Video Production Services to translate complex research into visually appealing presentations. Would you like to try it?

Confirm

Are you sure to Delete?
Cite
If you have any further questions, please contact Encyclopedia Editorial Office.
Kumar, V. Protein Quality Control (PQC). Encyclopedia. Available online: https://encyclopedia.pub/entry/7641 (accessed on 15 November 2024).
Kumar V. Protein Quality Control (PQC). Encyclopedia. Available at: https://encyclopedia.pub/entry/7641. Accessed November 15, 2024.
Kumar, Vijay. "Protein Quality Control (PQC)" Encyclopedia, https://encyclopedia.pub/entry/7641 (accessed November 15, 2024).
Kumar, V. (2021, March 01). Protein Quality Control (PQC). In Encyclopedia. https://encyclopedia.pub/entry/7641
Kumar, Vijay. "Protein Quality Control (PQC)." Encyclopedia. Web. 01 March, 2021.
Protein Quality Control (PQC)
Edit

Eukaryotic cells have a well-organized, tightly regulated protein quality control (PQC) system. This quality control system includes the molecular chaperones, ubiquitin/proteasome-dependent protein degradation, and autophagy machinery (target and uptake of non-native conformer in the spatial compartments) that consistently monitors and maintains the conformational state of cellular proteins.

protein misfolding molecular chaperones co-chaperone JUNQ IPOD

1. Introduction

In eukaryotic cells, this surveillance is done by various structurally unrelated molecular chaperones [1][2][3][4][5][6]. The members of these families have been termed heat shock proteins (HSPs). HSPs are classified according to their molecular weights (Hsp40, Hsp60, Hsp70, Hsp90, Hsp100, and small HSPs). Under stress conditions, these chaperones form a complex co-operative network and try to maintain the conformational state of cellular proteins. However, the proteins (misfolded/unfolded) that are unidentified by the PQC network exhibit toxicity for the cellular environment. To cope up with aberrant proteins, cells have several different ways to restore the integrity of a healthy proteome such as degradation via autophagy or ubiquitin-dependent proteolysis [7][8][9]. Error in the breakdown of aberrant polypeptides may result in protein aggregation which leads to pathological conditions such as Alzheimer’s disease (AD), Parkinson’s disease (PD), Huntington’s disease (HD), cataracts, and diabetes [10][11][12][13][14][15][16][17][18].

Several intracellular and extracellular stress factors can affect the integrity of the native protein, which causes severe damage either by loss of structure or the gain of toxic activity [19][20]. Recent studies suggest the involvement of environmental toxicants such as pesticides, air pollutants, and heavy metals. These environmental pollutants disrupt the PQCs network either by affecting molecular chaperones or proteasomal degradation machinery [21][22]. Sometimes these aggregates are prompt to sequestration in distinct subcellular compartments. These compartments are juxtanuclear quality control compartment (JUNQ), insoluble protein deposit (IPOD), and intranuclear quality control compartment (INQ). Recent studies indicate that co-chaperones are involved in the transfer process of aberrant proteins towards these compartments [1][23][24].

2. Essential Network of PQC

2.1. Aberrant Protein Processing by Molecular Chaperones

Many intracellular and extracellular factors like mutations, change in pH, temperature, and reactive oxygen species (ROS) levels, cause misfolding in proteins [25][26][27]. These misfolded proteins are recognized by molecular chaperones. These chaperones interact with misfolded conformers either by hydrophobic or electrostatic interactions followed by ATP hydrolysis. ATP hydrolysis causes conformational changes in the chaperone’s apical domain that forces the client protein to enter the chaperones’ cavity. Chaperones give enough time for a protein to fold by slowing down the rate of ATP hydrolysis [28]. The eukaryotic chaperone in tailless complex polypeptide 1 ring complex (TRiC) is an obligate chaperone for many proteins. In TRiC, folding occurs outside of the chamber [29][30][31][32].

The total time of insertion of misfolded proteins into the chaperone cavity depends upon the extent of protein’s hydrophobicity as well as ATP binding affinity of the molecular chaperone’s smaller subunit. For instance, TRiC has eight subunits and each of them has a different charge and different hydrophilic amino acids, therefore it shows a different affinity for client proteins and ATP. Hence, TRiC shows selective client binding and different ATP binding affinity [28][31][32][33][34][35][36][37].

The selectivity of client protein also depends on the type of co-chaperone. For instance, Hsp70 works with a co-chaperone known as J-protein (also called Hsp40). These J-proteins are known to have the J-domain. Human cells have 41 different kinds of J-proteins and all these have different selectivity for different client proteins. These J-domains, generally, are embedded inside the protein core which is exposed to stress conditions (denatured or misfolded protein) [34][35][36][37][38][39]. Therefore, exposure to these motifs indicates the presence of stress factors that affect the labile proteins. These stress damaged proteins interact with Hsp70 either by hydrophobic or electrostatic interactions. This binding affinity also depends upon the motion (opening and closing) of Hsp70’s α-helical lid located on the C-terminal of β sheet sub-domain [28][34][35][36][37][38][39]. This lid opening and closing is mediated by ATP hydrolysis [36][40]. The lid sub-domain C-terminal tail also shows an additional binding affinity for the client protein that increases the chances of rebinding when necessary [34][35][36][37][41][42].

Studies also show that client proteins after interaction with Hsp70 remain less structured for the entire duration of their folding. This strategy prevents proteins from undergoing a globular hydrophobic collapse [36][37][43]. Both stresses damaged as well as native proteins follow this trend during their synthesis [36][38]. Biophysical studies reveal that several different conformations are adopted by the lid subdomain and by the tail to provide accommodation for heavier and folded segments of the proteins. Different conformations of subdomain lid and tail allow Hsp70 to bind with unfolded polypeptides, folding intermediates, and near-native conformations by using a variety of different binding modes [34][35][36][37][39][44][45].

2.2. Molecular Co-Chaperone Interlinks Chaperones and Degradation Pathway

A potential misfolded protein is recognized and trapped by chaperones. These chaperones alleviate the toxicity of the misfolded conformers either by sequestering them or by modulating their conformation [11][19][46][47]. Chaperones are potentially engaged with the folding of newly synthesized proteins, their translocation, and the refolding of unfolded client proteins. In addition to these roles, chaperones also target misfolded conformers for degradation and transfer them in spatial compartments with the help of co-chaperones [1][11][19][47][48]. These co-chaperones have a combination of the domains that function in the ubiquitin-proteasome system (UPS) and chaperone interacting domain.

Co-chaperone carboxyl terminus of Hsc70-interacting protein (CHIP) and Bcl-2-associated athanogene-1 (BAG1) initially identified proteins having this structural feature and this finding gives an idea about direct communication between folding and degradation. BAG1 has a BAG domain and a ubiquitin-like (UBL) domain. BAG domain has Hsp70 nucleotide-binding activity and the UBL domain binds with 26S proteasome. CHIP has a tetratricopeptide repeat (TPR) domain, this TPR domain binds with Hsp70 and Hsp90 and a U-box with E3 ligase activity [49][50][51][52][53][54][55][56][57]. These findings suggest that the co-chaperone facilitates the delivery of substrates to protein degradation machinery. CHIP, Parkin, HSJ1a, BAG6, and UFD2B co-chaperones all have a domain for both interactions with a chaperone and function in the UPS (Table 1) [46].

Table 1. N-terminal and C-terminal domains of co-chaperones [46].

 

2.3. PQC Compartments: Final Steps of Protein Processing

Cellular inclusion is an integral part of the PQC system which seems to be conserved from yeast to mammalian cells [58][59][60]. These compartments are well known as the juxtanuclear quality control compartment (JUNQ), insoluble protein deposit (IPOD), and intranuclear quality control compartment (INQ). In these systems, misfolded proteins get sequestered for further processing either for refolding or degradation. Sorting of these misfolded proteins depends on a variety of characteristics such as misfold status, ubiquitination status, or chaperone interaction.

Chaperone interaction with misfolded proteins like Hsp110/Sse1, Hsp70/Ssa1, labels them for sequestration in Q-bodies and further targets them to the JUNQ compartment [1]. The IPOD sequestered proteins are generally non-ubiquitinated, immobile, non-diffusing, and insoluble. Under severe stress conditions, these IPODs act as a reservoir for misfolded protein [2] while JUNQ sequestered misfolded proteins are ubiquitinated and remain in a soluble state [2][61]. Studies have demonstrated that the JUNQ compartment forms near the surface of the nucleus during the time of proteasome impairment (Figure 1). Proteins are in a soluble state in the JUNQ compartment so they can diffuse easily. Thus, during stress conditions, JUNQ acts as a reservoir for misfolded protein clearance or refolding [2].

Figure 1. Multiple roles of molecular chaperones contributing to the management of misfolded proteins and cellular fitness. Exposure to intracellular or extracellular stress causes the formation of non-native protein conformer, which is identified and trapped by molecular chaperones through adenosine triphosphate (ATP) hydrolysis. Molecular chaperones refold misfolded proteins to their native conformation. In the case of protein folding failure, chaperones transfer misfolded proteins from chaperones to the UPS with the help of co-chaperones. E3 ubiquitin-ligase domains in co-chaperones recruit E3 ligases. E3 ligases further direct the ubiquitinated tagged protein towards the proteasome machinery for degradation and tagging them for ubiquitination. In some cases, these misfolded species are not recovered or are degraded by the PQC system due to the formation of soluble or insoluble aggregates. Insoluble aggregates sequester inside the IPOD while soluble aggregates/stress-damaged proteins sequester inside the Q-bodies. Under very high-stress conditions, soluble aggregates tend to JUNQ sequestration while some misfolded protein tends to sequester in INQ via Hsp70 co-chaperone Sis1 present in the nucleus. Inside the nucleus these misfolded aggregates either sequester in INQ by the blocking of CDC48 or target for degradation through ubiquitination via nuclear ubiquitin ligase San1.

If ubiquitination is blocked, then misfolded proteins are transported inside the nucleus where they get sequestered in INQ (Figure 1) with the blockage of CDC48 [62]. These misfolded proteins are also targeted for ubiquitination by San1 and then degraded by the proteasome inside the nucleus (Figure 1) [1]. Recent studies suggest that chaperones also target misfolded proteins toward different compartments, like Sis1 and Hij1, which are necessary for the Q-body formation and their maturation.

A family of chaperones called the hook family has members: Btn2 and Cur1. Both members have roles in the formation of IPOD and JUNQ [1][61]. Btn2 and Cur1 target misfolded proteins into these compartments in a small HSP (Hsp42)-dependent manner [61]. Hsp42 is a small ATP independent HSP, involved in the Q-body formation, during severe stress conditions. Hsp42 along with Hsp26 gets hyper-activated and co-localized with IPOD and other PQC sites. Hsp70 family member Ssa1/2 has a role in the refolding of misfolded proteins in Q-bodies and coalescence of Sis1 and Q-body targets the misfolded proteins toward INQ [2][63][64][65].

Hsp90 family member Hsc82 refolds proteins in Q-body and helps during the coalescence of Q-body with Ssa1/2 [63]. Co-chaperone HOP acts as a sorting factor and targets the aberrant proteins towards JUNQ. Chaperones Sis1 and Hsp40 also act similarly. Sis1 with V-SNARE binding protein Btn2 targets misfolded proteins to JUNQ and Sis 1 with Cur1 (curing of Ure3) targets misfolded proteins to IPOD. Chaperones Sis1 and Hsp70 together target the misfolded proteins towards INQ [24][38][61][66]. A small HSP like Hsp26 delivers the proteins towards spatial compartments under heat shock. Hsp42 with Btn2 targets proteins toward IPOD [67]. Sorting is also dependent upon ubiquitination.

From several studies [24][68], it has been shown that ubiquitin-labeled proteins are directed towards JUNQ. This compartment is highly concentrated with 26S proteasome subunits (lacking in IPOD). This suggests that the misfolded protein degradation in JUNQ happens in a ubiquitin-dependent manner [68]. Furthermore, these JUNQ compartments are also rich in disaggregating chaperones, therefore, facilitating misfolded protein disaggregation and refolding [2].

The location of IPOD (near the vacuoles, autophagic vesicles) suggests that IPOD sequestered misfolded proteins are targeted for degradation by auto-phagosome. Even though there is no functional link present between IPOD and autophagosome [2], evidence suggests the presence of an autophagic marker Atg8 in IPOD. This suggests that IPOD sequesters misfolded proteins that are cleared by the autophagic pathway [69][70][71].

3. Endoplasmic Reticulum-Associated PQC

The endoplasmic reticulum (ER) is the site for protein folding. The ER has multiple types of folding machinery that ensure that only the correctly folded proteins reach the site of action. When an unfolded protein reaches the ER lumen, Hsp70 co-chaperone Hsp40 binds to an unfolded protein [72][73]. In case of an error in the folding of proteins due to oxidation, mutation, or environmental stresses, there is a blockage of their release from the lumen of the ER into the cytosol. These misfolded proteins are required to relocate from the ER to the cytosol for degradation by the proteasome. These ER-associated misfolded proteins are processed by three pathways, namely: ER-associated degradation: ERAD-L (for misfolded ER lumenal proteins), ERAD-M (for ER-membrane proteins with a misfolded membrane domain), and ERAD-C (for ER membrane proteins with a misfolded cytosolic domain). All these pathways occur in the cytosol using specific types of machinery [74][75]. Ubiquitination of misfolded proteins occurs in the cytosol and they are further targeted towards proteasomal degradation. This process of PQC followed by proteasomal elimination of the misfolded protein is termed ER-associated degradation (ERAD), and it depends on an intricate interplay between the ER and the cytosol [76].

The mammalian system uses a combination of different proteins to accomplish the ER-linked PQC and ERAD. Proteins, namely BiP (GPR-78), ERdj6, ERdj1, ERdj2, ERdj3, ERdj4, ERdj5, OST (oligosaccharyl transferase complex), Glucosidase-I, Glucosidase-II, Calnexin, Calreticulin (CRP55), UGGT1, ERMan1, EDEM1, EDEM2, EDEM3, OS-9, XTP3-B, POMT1, POMT2, PDI, Hsp70, and Hsc70 are the modifiers, lectins, and chaperones helping in the ER-associated PQC while ERAD machinery comprises several different proteins, each having a specific function.

E3 ubiquitin ligase MARCH6 (TEB-4) helps during the membrane passage and ubiquitination. HRD, gp78, Sel-1L, Herp, Derlin-1, Derlin-2, and Derlin-3 help in the substrate re-translocation and ubiquitination. UBE1, UBE1L2 (MOP-4), Ubc6, HsUBC6e, Ube2G1, Ube2G2 (UBC7), Derlin-1, Derlin-2, and Derlin-3 are involved with the substrate ubiquitination process. Cdc48 (cell division cycle 48) complex’s protein including p97 (VCP), UFD1, NPL4, and Ubxd8 (FAF2) are involved with the extraction of the substrate from the ER and further target it for the ubiquitination process. PLC1, PLC2, (Ubiquilin3, A1Up) hHR23a, and hHR23b are the shuttling factors that shuttle the ubiquitinated substrate towards the proteasome. Substrates of the ERAD pathways are marked with ubiquitin chain with the help of ubiquitin-conjugating enzymes (E1, E2, and E3). After ubiquitination, the tagged protein is identified by 26S proteasome (RPN1, RPN10, and RPN13), deubiquitinated RPN11 (PSMD14), and further degraded, this pathway is important for the degradation of ERAD aberrant protein [76][77][78][79].

4. Environmental Pollutants: Effect on PQC

4.1. Protein Degradation Machinery

Proteolysis mediated by ubiquitin plays an important role in several basic cellular processes. Disruption in this pathway leads to the accumulation of misfolded proteins in the cell. As proteolysis is accompanied by the ubiquitination process, the target protein is first processed by the Ubiquitin-Activating Enzyme (E1). This enzyme activates the ubiquitin by hydrolyzing the ATP. The resultant of this step is an E1-thiol-ester∼ubiquitin intermediate. The activated E1-ubiquitin moiety is further transferred to E2, a ubiquitin-conjugating enzyme [80][81]. E2 either conjugates the ubiquitin to the target protein or transfers the E1-ubiquitin moiety to an E3-ubiquitin intermediate. The E2 active site is comprised of the presence of the ubiquitin-conjugating enzymes (UBC) domain (required for the binding with E3) and a ubiquitin-binding Cys residue [82]. Currently, many E2 have been identified, among them Ubc4 and Ubc5 are involved with the targeting of misfolded/short-lived proteins. Another E2, Ubc3/Cdc34, is involved with the targeting of phosphorylated substrates. The number, variety, and function of different E2s in mammalian species are much greater and are still being explored. The E3, ubiquitin-protein ligase enzyme is engaged with the recognition of substrates of the ubiquitin system. E3 ligases are binds with both E2 and substrates. In most cases, E3 act as a scaffold to bring together the E2 and substrate; this process allows the transfer of ubiquitin moiety from E2 to the substrate [77][79][83][84][85][86].

After the ubiquitination process, the protolysis work of the target protein is conducted by 26S proteasome machinery. The 26S machinery is comprised of a 20S core and 19S cap. Their functional state attains a cylinder-like structure, where the 19S cap recognizes the substrate while the degradation work is achieved by 20S core moiety. The core of 20S has been shown to have a proteolytic active site. This complex is made up of four to seven numbered rings, in which two outer rings are known as α ring while the central side ring is known as β-ring. The proteolytic activity is carried only by β-ring [87][88][89][90][91][92]. In archaea, these β-rings have shown the chymotrypsin-like, trypsin-like, and peptidyl-glutamyl-peptide hydrolyzing activity [93].

4.2. Effect of Pesticide on Proteasome Degradation Machinery

The wide use of pesticides causes huge human encounters daily. These pesticides may enter the human body in different ways. Though the human body can neutralize these chemical effects, epidemiological studies demonstrate their toxicity linked to several diseases especially proteinopathies such as PD [94][95][96]. However, the mechanism behind their toxicity is still elusive.

Rotenone, an organic pesticide, has been extensively studied for PD pathogenesis. Rotenone treatment in rats shows a dopaminergic neuronal loss, ROS generation, and motor dysfunction [97][98]. Its toxicity on mitochondrial complex-1 elevates oxidative stress [99][100]. Though rotenone causes oxidative stress, its role in causing cellular death is far more than assumed. UPS is the site for protein degradation. Several studies highlight rotenone toxicity in the UPS [21][101][102][103][104][105]. One study has shown that rotenone causes mitochondrial inhibition, oxidative stress, microtubule assembly, and increased degradation of proteasomal subunits (mechanisms of rotenone-induced proteasome inhibition).

Benomyl, dieldrin, diethyldithiocarbamate, endosulfan, and ziram significantly inhibit the proteasome activity in human neuroblastoma cell line SK-N-MCU [104]. Another study conducted in China reveals that the nine most frequently used pesticides (paraquat, rotenone, chlorpyrifos, pendimethalin, endosulfan, fenpyroximate, tebufenpyrad, trichlorphon, and carbaryl) induce morphological changes in the mitochondria at low concentrations. These pesticides are known to induce mitochondrial fragmentation. Interestingly, they also significantly suppress the activity of 26S and 20S proteasome [106]. Another study conducted on wild type mice depicts the ability of low dose paraquat, maneb, and chlorpyrifos to affect the 26S proteasome complex. Paraquat and its co-treatment with maneb or chlorpyrifos were found to be toxic and inhibited all soluble proteasomal expression of 26S proteasomal subunits [107]. Ziram, a fungicide, induces the primary ventral mesencephalic cell death by interfering with the UPS (26S) activity. Mechanistically, ziram inhibits the ubiquitin-activating enzyme (E1), thus altering UPS function [108].

4.3. Effect of Heavy Metal on Proteasome Degradation Machinery

Heavy metals are naturally occurring element present in the Earth’s crust, but haphazard human activity alters the geochemical balance. Huge human exposure causes a harmful effect. Earlier studies show that their exposure can cause various disorders including metabolic and neurological disorders also associated with lethal diseases [109][110]. These heavy metals also affect the PQC system especially the proteasome machinery. Cadmium is a divalent cation that significantly impairs proteasome activity. This impairment leads to an increase in the formation of soluble and insoluble ubiquitinated proteins [22]. Another study reveals that gallium containing compound inhibits cellular 26S proteasome and chymotrypsin-like activity of the purified 20S proteasome with IC50 values of 17 and 16 μmol/L [111].

Organic copper complexes also potentially inhibit the chymotrypsin-like activity of purified 20S proteasome. In human leukemia cells, proteasome inhibition occurs within 15 min after organic copper complexes exposure [112]. Cobalt induces apoptosis in the lung by disturbing the ubiquitin-proteasome pathway. In U-937 cells and human alveolar macrophages (AMs), exposure to cobalt chloride (CoCl2) induces apoptosis and accumulation of ubiquitinated proteins. Exposure to CoCl2 also suppresses the activity of the proteasome, although the inhibitory effect of CoCl2 (1000 μM) on proteasome activity is not as potent as that of MG-132 (proteasome inhibitor) (100 μM) [113].

Arsenic (As) is a metalloid that is rarely found as a free element in the natural environment. Arsenic has many pharmacological properties; however, due to its toxic property it has not gained much attention. Arsenic also causes perturbation of proteasome degradation machinery. Exposure of NaAsO2 on HEK293T, GM00637, IMR90, HEK293T, and NB4 APL cells shows significant impairment of enzymatic activities of ZnF containing E3 ubiquitin ligases. As2O3 exposure on NB4 APL cells also shows similar effects. Arsenate exposure on NIH3T3 and DTC25 cells result in the compromised functions of p97 and proteasome [114]. Arsenic exposure to HT22 cells leads to inactivation of proteasome machinery, damage in the electron transport chain, and an increase in oxidative stress [115].

4.4. Effect of Air Pollution on Proteasome Degradation Machinery

Epidemiological studies consistently document the relationship between increased risk of human disease with ambient air pollutants and particulate matter (PM) [116]. Several mechanistic studies provide insight for their deleterious outcome towards humans but all this information is still not enough to elaborate their mode of toxicity at the cellular and molecular level. Yet, few studies exist that exhibit their toxicity on the PQC system.

Exposure to two distinct experimental aerosols, diesel exhaust and secondary organic aerosol (DE and SOA), produces a rapid (within 30 min post-exposure) and consistent decrease in proteasome activity in two different peripheral blood cell types [117]. Though their immediate exposure causes a decrease in proteasome activity, their mechanism is still lacking. Both DE and SOA are directly associated with oxidative and nitrosative stress hence, the two might be directly associated with the decreased proteasomal activity. They are likely to play a role in response to PM in the air [118].

Cigarette smoke extract (CSE) treatment on human alveolar epithelial cells induced time and dose-dependent cell death. It also elevated the intracellular ROS and increased the level of carbonylated and polyubiquitinated proteins. Further, high doses of CSE impaired all proteasomal activities, while low CSE concentrations significantly inhibited only the trypsin-like activity of the proteasome in alveolar and bronchial epithelial cells [119].

4.5. Effect of Environmental Pollutants on ER-Associated PQC

Several studies reveal the toxicity of environmental pollutants on ER-associated PQC. These environmental pollutants, including pesticides and heavy metals, and certain nanoparticles show significant involvement in the disturbance of ER-associated PQC. Pyrethroids like insecticides are widely used on insects and pests in agriculture and public health. In recent years, pyrethroid-associated toxicity has risen dramatically. Pyrethroids exposure is also associated with the increasing incidences of neurodegenerative diseases [120][121][122][123][124][125].

Recent studies reveal their link with apoptosis, but the mechanism is still lacking. Some studies have found that deltamethrin pesticide initiates the apoptotic cascade through interaction with Na+ channels, leading to calcium overload and initiation of the apoptotic cascade. Studies have identified the role of calpain and the ER stress pathway as mediators of deltamethrin-induced apoptosis [126]. Exposure of permethrin on 3T3-L1 adipocytes and 3T3-L1 cells induces ER stress via changing the intracellular calcium level also elevates the level of ER stress marker protein [127].

Another class of pesticides, the organophosphates are associated with hampering the quality control of the ER. Treatment of chlorpyrifos (CPF) of 50 μM or 100 μM on human choriocarcinoma trophoblastic cells JEG-3 cells for 24 h induces an increase of ER stress-related proteins, such as GRP78/BiP and IRE1α and also causes the mRNA splicing of phospho-eIF2α and XBP1 [128]. Like pesticides, heavy metals are also potentially toxic for ER exhibiting toxicity via inducing unfolded protein response in ER (UPR). Treatment of cadmium (Cd) in Saccharomyces cerevisiae triggers the UPR via activating Ire1. Silver nanoparticles (AgNP), widely used in the medical field, are also reported to cause cytotoxicity via induction of apoptosis. Treatment of AgNP on human MCF-7 and T-47D breast cancer cells shows the accumulation of misfolded/aggregated proteins and induction of ER stress via activation of UPR [129].

During the ERAD process, the ERAD adaptor protein Ubx2 plays a role as the bridging factor. Ubx2 transports the misfolded proteins from the ER to the cytosol for ubiquitylation and proteasomal degradation. Recently, a study represented the Cd toxicity in Saccharomyces cerevisiae. Cd exposure in Saccharomyces cerevisiae induces the ER stress and causes the upregulation of ER stress-responsive genes (HAC1, IRE1, ERO1, and PDI1), heat shock responsive genes (HSP104 and HSP60), ERAD pathway genes (DOA10, CDC48, HRD1, and YOS9), and proteasome regulators (UBI4 and RPN4) [130].

4.6. Effect of Environmental Pollutant on Autophagy

PQC is accomplished by molecular chaperones and targeted protein degradation [131]. Targeted protein degradation is primarily performed by the ubiquitin-proteasome system (UPS). Recently, it has been established that the autophagic-lysosomal pathway (ALP) plays an important part in the removal of the aggregated form of misfolded proteins [132]. Hence, the UPS and the ALP are the final part of the defense against proteotoxicity.

Heavy metals and metalloids are proven to have a hazardous impact on humans [109]. Arsenic (As) is generally present in the environment in its two oxidative forms such as arsenous acid (H3AsO3) and its salts, and arsenic acid (H3AsO5) and its salts. Arsenic trioxide (As2O3) is majorly used as a pharmaceutical agent for its antitumor properties. Exposure of As2O3 leads to the activation of numerous intracellular signal transduction pathways such as ROS generation, mitochondrial disruption, and caspase activation resulting in the induction of apoptosis [133].

Current research has revealed that under As stress condition, autophagy could be initiated in place of apoptosis, as one study showed that As2O3 significantly induces autophagic cell death in leukemic cell lines [134][135]. Chromium in combination with cadmium can potentially induce autophagy. Co-treatment of cadmium and chromium in hematopoietic stem/progenitor cells (HSPC) induces autophagic morphologies. Toxic compounds that can potentially induce autophagy are summarized in Table 2.

Table 2. List of toxic compounds that induce autophagy.

References

  1. Sontag, E.M.; Samant, R.S.; Frydman, J. Mechanisms and Functions of Spatial Protein Quality Control. Annu. Rev. Biochem. 2017, 86, 97–122.
  2. Kaganovich, D.; Kopito, R.; Frydman, J. Misfolded proteins partition between two distinct quality control compartments. Nature 2008, 454, 1088–1095.
  3. Peters, L.Z.; Karmon, O.; David-Kadoch, G.; Hazan, R.; Yu, T.; Glickman, M.H.; Ben-Aroya, S. The protein quality control machinery regulates its misassembled proteasome subunits. PLoS Genet. 2015, 11, e1005178.
  4. Pilla, E.; Schneider, K.; Bertolotti, A. Coping with Protein Quality Control Failure. Annu. Rev. Cell Dev. Biol. 2017, 33, 439–465.
  5. Dikic, I. Proteasomal and Autophagic Degradation Systems. Annu. Rev. Biochem. 2017, 86, 193–224.
  6. Kim, Y.E.; Hipp, M.S.; Bracher, A.; Hayer-Hartl, M.; Hartl, F.U. Molecular chaperone functions in protein folding and proteostasis. Annu. Rev. Biochem. 2013, 82, 323–355.
  7. Wang, Y.; Le, W.-D. Autophagy and Ubiquitin-Proteasome System. In Autophagy: Biology and Diseases: Basic Science; Qin, Z.-H., Ed.; Springer: Singapore, 2019; pp. 527–550.
  8. Nedelsky, N.B.; Todd, P.K.; Taylor, J.P. Autophagy and the ubiquitin-proteasome system: Collaborators in neuroprotection. Biochim. Biophys. Acta 2008, 1782, 691–699.
  9. Kocaturk, N.M.; Gozuacik, D. Crosstalk between Mammalian Autophagy and the Ubiquitin-Proteasome System. Front. Cell Dev. Biol. 2018, 6, 128.
  10. Lazarev, V.F.; Mikhaylova, E.R.; Guzhova, I.V.; Margulis, B.A. Possible Function of Molecular Chaperones in Diseases Caused by Propagating Amyloid Aggregates. Front. Neurosci. 2017, 11, 277.
  11. Hervas, R.; Oroz, J. Mechanistic Insights into the Role of Molecular Chaperones in Protein Misfolding Diseases: From Molecular Recognition to Amyloid Disassembly. Int. J. Mol. Sci. 2020, 21, 9186.
  12. Camberg, J.L.; Doyle, S.M.; Johnston, D.M.; Wickner, S. Molecular Chaperones. In Brenner’s Encyclopedia of Genetics; Maloy, S., Hughes, K., Eds.; Academic Press: San Diego, CA, USA, 2013; pp. 456–460.
  13. Bobori, C.; Theocharopoulou, G.; Vlamos, P. Molecular Chaperones in Neurodegenerative Diseases: A Short Review. Adv. Exp. Med. Biol. 2017, 987, 219–231.
  14. Stroo, E.; Koopman, M.; Nollen, E.A.; Mata-Cabana, A. Cellular Regulation of Amyloid Formation in Aging and Disease. Front. Neurosci. 2017, 11, 64.
  15. Ciechanover, A.; Kwon, Y.T. Protein Quality Control by Molecular Chaperones in Neurodegeneration. Front. Neurosci. 2017, 11, 185.
  16. Bohush, A.; Bieganowski, P.; Filipek, A. Hsp90 and Its Co-Chaperones in Neurodegenerative Diseases. Int. J. Mol. Sci. 2019, 20, 4976.
  17. Gestwicki, J.E.; Garza, D. Chapter 10—Protein Quality Control in Neurodegenerative Disease. In Progress in Molecular Biology and Translational Science; Teplow, D.B., Ed.; Academic Press: Cambridge, MA, USA, 2012; Volume 107, pp. 327–353.
  18. Joshi, N.; Raveendran, A.; Nagotu, S. Chaperones and Proteostasis: Role in Parkinson’s Disease. Diseases 2020, 8, 24.
  19. Hartl, F.U.; Bracher, A.; Hayer-Hartl, M. Molecular chaperones in protein folding and proteostasis. Nature 2011, 475, 324–332.
  20. Morimoto, R.I. The heat shock response: Systems biology of proteotoxic stress in aging and disease. Cold Spring Harb. Symp. Quant. Biol. 2011, 76, 91–99.
  21. Chou, A.P.; Li, S.; Fitzmaurice, A.G.; Bronstein, J.M. Mechanisms of rotenone-induced proteasome inhibition. Neurotoxicology 2010, 31, 367–372.
  22. Kanthasamy, A.G.; Choi, C.; Jin, H.; Harischandra, D.S.; Anantharam, V.; Kanthasamy, A. Effect of divalent metals on the neuronal proteasomal system, prion protein ubiquitination and aggregation. Toxicol. Lett. 2012, 214, 288–295.
  23. Hill, S.M.; Hanzen, S.; Nystrom, T. Restricted access: Spatial sequestration of damaged proteins during stress and aging. EMBO Rep. 2017, 18, 377–391.
  24. Miller, S.B.; Ho, C.T.; Winkler, J.; Khokhrina, M.; Neuner, A.; Mohamed, M.Y.; Guilbride, D.L.; Richter, K.; Lisby, M.; Schiebel, E.; et al. Compartment-specific aggregases direct distinct nuclear and cytoplasmic aggregate deposition. EMBO J. 2015, 34, 778–797.
  25. Gregersen, N.; Bross, P. Protein misfolding and cellular stress: An overview. Methods Mol. Biol. 2010, 648, 3–23.
  26. Abramov, A.Y.; Potapova, E.V.; Dremin, V.V.; Dunaev, A.V. Interaction of Oxidative Stress and Misfolded Proteins in the Mechanism of Neurodegeneration. Life 2020, 10, 101.
  27. Santos, C.X.; Tanaka, L.Y.; Wosniak, J.; Laurindo, F.R. Mechanisms and implications of reactive oxygen species generation during the unfolded protein response: Roles of endoplasmic reticulum oxidoreductases, mitochondrial electron transport, and NADPH oxidase. Antioxid. Redox Signal. 2009, 11, 2409–2427.
  28. Koldewey, P.; Horowitz, S.; Bardwell, J.C.A. Chaperone-client interactions: Non-specificity engenders multifunctionality. J. Biol. Chem. 2017, 292, 12010–12017.
  29. Balchin, D.; Hayer-Hartl, M.; Hartl, F.U. In vivo aspects of protein folding and quality control. Science 2016, 353, aac4354.
  30. Jin, M.; Liu, C.; Han, W.; Cong, Y. TRiC/CCT Chaperonin: Structure and Function. In Macromolecular Protein Complexes II: Structure and Function; Harris, J.R., Marles-Wright, J., Eds.; Springer: Cham, Switzerland, 2019; pp. 625–654.
  31. Grantham, J. The Molecular Chaperone CCT/TRiC: An Essential Component of Proteostasis and a Potential Modulator of Protein Aggregation. Front. Genet. 2020, 11, 172.
  32. Gestaut, D.; Roh, S.H.; Ma, B.; Pintilie, G.; Joachimiak, L.A.; Leitner, A.; Walzthoeni, T.; Aebersold, R.; Chiu, W.; Frydman, J. The Chaperonin TRiC/CCT Associates with Prefoldin through a Conserved Electrostatic Interface Essential for Cellular Proteostasis. Cell 2019, 177, 751–765.e715.
  33. Reissmann, S.; Joachimiak, L.A.; Chen, B.; Meyer, A.S.; Nguyen, A.; Frydman, J. A gradient of ATP affinities generates an asymmetric power stroke driving the chaperonin TRIC/CCT folding cycle. Cell Rep. 2012, 2, 866–877.
  34. Lackie, R.E.; Maciejewski, A.; Ostapchenko, V.G.; Marques-Lopes, J.; Choy, W.Y.; Duennwald, M.L.; Prado, V.F.; Prado, M.A.M. The Hsp70/Hsp90 Chaperone Machinery in Neurodegenerative Diseases. Front. Neurosci. 2017, 11, 254.
  35. Mayer, M.P.; Gierasch, L.M. Recent advances in the structural and mechanistic aspects of Hsp70 molecular chaperones. J. Biol. Chem. 2019, 294, 2085–2097.
  36. Rosenzweig, R.; Nillegoda, N.B.; Mayer, M.P.; Bukau, B. The Hsp70 chaperone network. Nat. Rev. Mol. Cell Biol. 2019, 20, 665–680.
  37. Liu, Q.; Liang, C.; Zhou, L. Structural and functional analysis of the Hsp70/Hsp40 chaperone system. Protein Sci. 2020, 29, 378–390.
  38. Clerico, E.M.; Tilitsky, J.M.; Meng, W.; Gierasch, L.M. How hsp70 molecular machines interact with their substrates to mediate diverse physiological functions. J. Mol. Biol. 2015, 427, 1575–1588.
  39. Shiber, A.; Ravid, T. Chaperoning Proteins for Destruction: Diverse Roles of Hsp70 Chaperones and their Co-Chaperones in Targeting Misfolded Proteins to the Proteasome. Biomolecules 2014, 4, 704–724.
  40. Zhuravleva, A.; Gierasch, L.M. Substrate-binding domain conformational dynamics mediate Hsp70 allostery. Proc. Natl. Acad. Sci. USA 2015, 112, E2865–E2873.
  41. Hu, S.M.; Wang, C. Involvement of the 10-kDa C-terminal fragment of hsc70 in complexing with unfolded protein. Arch. Biochem. Biophys. 1996, 332, 163–169.
  42. Zhang, P.; Leu, J.I.; Murphy, M.E.; George, D.L.; Marmorstein, R. Crystal structure of the stress-inducible human heat shock protein 70 substrate-binding domain in complex with peptide substrate. PLoS ONE 2014, 9, e103518.
  43. Motojima, F. How do chaperonins fold protein? Biophysics (Nagoya-Shi) 2015, 11, 93–102.
  44. Schlecht, R.; Erbse, A.H.; Bukau, B.; Mayer, M.P. Mechanics of Hsp70 chaperones enables differential interaction with client proteins. Nat. Struct. Mol. Biol. 2011, 18, 345–351.
  45. Mashaghi, A.; Bezrukavnikov, S.; Minde, D.P.; Wentink, A.S.; Kityk, R.; Zachmann-Brand, B.; Mayer, M.P.; Kramer, G.; Bukau, B.; Tans, S.J. Alternative modes of client binding enable functional plasticity of Hsp70. Nature 2016, 539, 448–451.
  46. McClellan, A.J.; Tam, S.; Kaganovich, D.; Frydman, J. Protein quality control: Chaperones culling corrupt conformations. Nat. Cell Biol. 2005, 7, 736–741.
  47. Broadley, S.A.; Hartl, F.U. The role of molecular chaperones in human misfolding diseases. FEBS Lett. 2009, 583, 2647–2653.
  48. Jiang, Y.; Douglas, N.R.; Conley, N.R.; Miller, E.J.; Frydman, J.; Moerner, W.E. Sensing cooperativity in ATP hydrolysis for single multisubunit enzymes in solution. Proc. Natl. Acad. Sci. USA 2011, 108, 16962–16967.
  49. Frydman, J. Folding of newly translated proteins in vivo: The role of molecular chaperones. Annu. Rev. Biochem. 2001, 70, 603–647.
  50. Cyr, D.M.; Hohfeld, J.; Patterson, C. Protein quality control: U-box-containing E3 ubiquitin ligases join the fold. Trends Biochem. Sci. 2002, 27, 368–375.
  51. McDonough, H.; Patterson, C. CHIP: A link between the chaperone and proteasome systems. Cell Stress Chaperones 2003, 8, 303–308.
  52. Esser, C.; Alberti, S.; Hohfeld, J. Cooperation of molecular chaperones with the ubiquitin/proteasome system. Biochim. Biophys. Acta 2004, 1695, 171–188.
  53. Edkins, A.L. CHIP: A co-chaperone for degradation by the proteasome. Sub-Cell. Biochem. 2015, 78, 219–242.
  54. Hoter, A.; El-Sabban, M.E.; Naim, H.Y. The HSP90 Family: Structure, Regulation, Function, and Implications in Health and Disease. Int. J. Mol. Sci. 2018, 19, 2560.
  55. Alberti, S.; Esser, C.; Hohfeld, J. BAG-1—A nucleotide exchange factor of Hsc70 with multiple cellular functions. Cell Stress Chaperones 2003, 8, 225–231.
  56. Luders, J.; Demand, J.; Hohfeld, J. The ubiquitin-related BAG-1 provides a link between the molecular chaperones Hsc70/Hsp70 and the proteasome. J. Biol. Chem. 2000, 275, 4613–4617.
  57. Quintana-Gallardo, L.; Martin-Benito, J.; Marcilla, M.; Espadas, G.; Sabido, E.; Valpuesta, J.M. The cochaperone CHIP marks Hsp70- and Hsp90-bound substrates for degradation through a very flexible mechanism. Sci. Rep. 2019, 9, 5102.
  58. Chiti, F.; Dobson, C.M. Protein Misfolding, Amyloid Formation, and Human Disease: A Summary of Progress Over the Last Decade. Annu. Rev. Biochem. 2017, 86, 27–68.
  59. Outeiro, T.F.; Lindquist, S. Yeast cells provide insight into alpha-synuclein biology and pathobiology. Science 2003, 302, 1772–1775.
  60. Rubinsztein, D.C. The roles of intracellular protein-degradation pathways in neurodegeneration. Nature 2006, 443, 780–786.
  61. Malinovska, L.; Kroschwald, S.; Munder, M.C.; Richter, D.; Alberti, S. Molecular chaperones and stress-inducible protein-sorting factors coordinate the spatiotemporal distribution of protein aggregates. Mol. Biol. Cell 2012, 23, 3041–3056.
  62. Gallagher, P.S.; Clowes Candadai, S.V.; Gardner, R.G. The requirement for Cdc48/p97 in nuclear protein quality control degradation depends on the substrate and correlates with substrate insolubility. J. Cell Sci. 2014, 127, 1980–1991.
  63. Escusa-Toret, S.; Vonk, W.I.; Frydman, J. Spatial sequestration of misfolded proteins by a dynamic chaperone pathway enhances cellular fitness during stress. Nat. Cell Biol. 2013, 15, 1231–1243.
  64. Park, S.H.; Kukushkin, Y.; Gupta, R.; Chen, T.; Konagai, A.; Hipp, M.S.; Hayer-Hartl, M.; Hartl, F.U. PolyQ proteins interfere with nuclear degradation of cytosolic proteins by sequestering the Sis1p chaperone. Cell 2013, 154, 134–145.
  65. Saarikangas, J.; Barral, Y. Protein aggregates are associated with replicative aging without compromising protein quality control. Elife 2015, 4, e06197.
  66. Walters, R.W.; Muhlrad, D.; Garcia, J.; Parker, R. Differential effects of Ydj1 and Sis1 on Hsp70-mediated clearance of stress granules in Saccharomyces cerevisiae. RNA 2015, 21, 1660–1671.
  67. Specht, S.; Miller, S.B.; Mogk, A.; Bukau, B. Hsp42 is required for sequestration of protein aggregates into deposition sites in Saccharomyces cerevisiae. J. Cell Biol. 2011, 195, 617–629.
  68. Bagola, K.; Sommer, T. Protein quality control: On IPODs and other JUNQ. Curr. Biol. 2008, 18, R1019–R1021.
  69. Hyttinen, J.M.; Amadio, M.; Viiri, J.; Pascale, A.; Salminen, A.; Kaarniranta, K. Clearance of misfolded and aggregated proteins by aggrephagy and implications for aggregation diseases. Ageing Res. Rev. 2014, 18, 16–28.
  70. Khaminets, A.; Behl, C.; Dikic, I. Ubiquitin-Dependent And Independent Signals In Selective Autophagy. Trends Cell Biol. 2016, 26, 6–16.
  71. Nilsson, P.; Loganathan, K.; Sekiguchi, M.; Matsuba, Y.; Hui, K.; Tsubuki, S.; Tanaka, M.; Iwata, N.; Saito, T.; Saido, T.C. Abeta secretion and plaque formation depend on autophagy. Cell Rep. 2013, 5, 61–69.
  72. Van Anken, E.; Braakman, I. Versatility of the endoplasmic reticulum protein folding factory. Crit. Rev. Biochem. Mol. Biol. 2005, 40, 191–228.
  73. Verghese, J.; Abrams, J.; Wang, Y.; Morano, K.A. Biology of the heat shock response and protein chaperones: Budding yeast (Saccharomyces cerevisiae) as a model system. Microbiol. Mol. Biol. Rev. 2012, 76, 115–158.
  74. Carvalho, P.; Goder, V.; Rapoport, T.A. Distinct ubiquitin-ligase complexes define convergent pathways for the degradation of ER proteins. Cell 2006, 126, 361–373.
  75. Vashist, S.; Ng, D.T. Misfolded proteins are sorted by a sequential checkpoint mechanism of ER quality control. J. Cell Biol. 2004, 165, 41–52.
  76. Berner, N.; Reutter, K.R.; Wolf, D.H. Protein Quality Control of the Endoplasmic Reticulum and Ubiquitin-Proteasome-Triggered Degradation of Aberrant Proteins: Yeast Pioneers the Path. Annu. Rev. Biochem. 2018, 87, 751–782.
  77. Liu, W.; Tang, X.; Qi, X.; Fu, X.; Ghimire, S.; Ma, R.; Li, S.; Zhang, N.; Si, H. The Ubiquitin Conjugating Enzyme: An Important Ubiquitin Transfer Platform in Ubiquitin-Proteasome System. Int. J. Mol. Sci. 2020, 21, 2894.
  78. Deol, K.K.; Lorenz, S.; Strieter, E.R. Enzymatic Logic of Ubiquitin Chain Assembly. Front. Physiol. 2019, 10, 835.
  79. Deng, L.; Meng, T.; Chen, L.; Wei, W.; Wang, P. The role of ubiquitination in tumorigenesis and targeted drug discovery. Signal Transduct. Target. 2020, 5, 11.
  80. Hershko, A.; Heller, H.; Elias, S.; Ciechanover, A. Components of ubiquitin-protein ligase system. Resolution, affinity purification, and role in protein breakdown. J. Biol. Chem. 1983, 258, 8206–8214.
  81. Zheng, N.; Shabek, N. Ubiquitin Ligases: Structure, Function, and Regulation. Annu. Rev. Biochem. 2017, 86, 129–157.
  82. Kalchman, M.A.; Graham, R.K.; Xia, G.; Koide, H.B.; Hodgson, J.G.; Graham, K.C.; Goldberg, Y.P.; Gietz, R.D.; Pickart, C.M.; Hayden, M.R. Huntingtin is ubiquitinated and interacts with a specific ubiquitin-conjugating enzyme. J. Biol. Chem. 1996, 271, 19385–19394.
  83. Deshaies, R.J. SCF and Cullin/Ring H2-based ubiquitin ligases. Annu. Rev. Cell Dev. Biol. 1999, 15, 435–467.
  84. Williams, K.M.; Qie, S.; Atkison, J.H.; Salazar-Arango, S.; Alan Diehl, J.; Olsen, S.K. Structural insights into E1 recognition and the ubiquitin-conjugating activity of the E2 enzyme Cdc34. Nat. Commun. 2019, 10, 3296.
  85. Valimberti, I.; Tiberti, M.; Lambrughi, M.; Sarcevic, B.; Papaleo, E. E2 superfamily of ubiquitin-conjugating enzymes: Constitutively active or activated through phosphorylation in the catalytic cleft. Sci. Rep. 2015, 5, 14849.
  86. Stewart, M.D.; Ritterhoff, T.; Klevit, R.E.; Brzovic, P.S. E2 enzymes: More than just middle men. Cell Res. 2016, 26, 423–440.
  87. Rohrwild, M.; Coux, O.; Huang, H.C.; Moerschell, R.P.; Yoo, S.J.; Seol, J.H.; Chung, C.H.; Goldberg, A.L. HslV-HslU: A novel ATP-dependent protease complex in Escherichia coli related to the eukaryotic proteasome. Proc. Natl. Acad. Sci. USA 1996, 93, 5808–5813.
  88. Tanaka, K. The proteasome: Overview of structure and functions. Proc. Jpn. Acad. Ser. B Phys. Biol. Sci. 2009, 85, 12–36.
  89. Voges, D.; Zwickl, P.; Baumeister, W. The 26S proteasome: A molecular machine designed for controlled proteolysis. Annu. Rev. Biochem. 1999, 68, 1015–1068.
  90. Livneh, I.; Cohen-Kaplan, V.; Cohen-Rosenzweig, C.; Avni, N.; Ciechanover, A. The life cycle of the 26S proteasome: From birth, through regulation and function, and onto its death. Cell Res. 2016, 26, 869–885.
  91. Coux, O.; Tanaka, K.; Goldberg, A.L. Structure and functions of the 20S and 26S proteasomes. Annu. Rev. Biochem. 1996, 65, 801–847.
  92. Zwickl, P.; Voges, D.; Baumeister, W. The proteasome: A macromolecular assembly designed for controlled proteolysis. Philos. Trans. R. Soc. London Ser. B Biol. Sci. 1999, 354, 1501–1511.
  93. Wolf, D.H.; Hilt, W. The proteasome: A proteolytic nanomachine of cell regulation and waste disposal. Biochim. Biophys. Acta 2004, 1695, 19–31.
  94. Drouin-Ouellet, J.; Cicchetti, F. Pesticides and Parkinson’s Disease; IntechOpen: London, UK, 2011.
  95. Baldi, I.; Lebailly, P.; Mohammed-Brahim, B.; Letenneur, L.; Dartigues, J.F.; Brochard, P. Neurodegenerative diseases and exposure to pesticides in the elderly. Am. J. Epidemiol. 2003, 157, 409–414.
  96. Brown, T.P.; Rumsby, P.C.; Capleton, A.C.; Rushton, L.; Levy, L.S. Pesticides and Parkinson’s disease—Is there a link? Environ. Health Perspect. 2006, 114, 156–164.
  97. Fleming, S.M.; Zhu, C.; Fernagut, P.O.; Mehta, A.; DiCarlo, C.D.; Seaman, R.L.; Chesselet, M.F. Behavioral and immunohistochemical effects of chronic intravenous and subcutaneous infusions of varying doses of rotenone. Exp. Neurol. 2004, 187, 418–429.
  98. Betarbet, R.; Sherer, T.B.; Di Monte, D.A.; Greenamyre, J.T. Mechanistic approaches to Parkinson’s disease pathogenesis. Brain Pathol. 2002, 12, 499–510.
  99. Barrientos, A.; Moraes, C.T. Titrating the effects of mitochondrial complex I impairment in the cell physiology. J. Biol. Chem. 1999, 274, 16188–16197.
  100. Kudin, A.P.; Malinska, D.; Kunz, W.S. Sites of generation of reactive oxygen species in homogenates of brain tissue determined with the use of respiratory substrates and inhibitors. Biochim. Biophys. Acta 2008, 1777, 689–695.
  101. Leroy, E.; Boyer, R.; Auburger, G.; Leube, B.; Ulm, G.; Mezey, E.; Harta, G.; Brownstein, M.J.; Jonnalagada, S.; Chernova, T.; et al. The ubiquitin pathway in Parkinson’s disease. Nature 1998, 395, 451–452.
  102. Kitada, T.; Asakawa, S.; Hattori, N.; Matsumine, H.; Yamamura, Y.; Minoshima, S.; Yokochi, M.; Mizuno, Y.; Shimizu, N. Mutations in the parkin gene cause autosomal recessive juvenile parkinsonism. Nature 1998, 392, 605–608.
  103. McNaught, K.S.; Mytilineou, C.; Jnobaptiste, R.; Yabut, J.; Shashidharan, P.; Jennert, P.; Olanow, C.W. Impairment of the ubiquitin-proteasome system causes dopaminergic cell death and inclusion body formation in ventral mesencephalic cultures. J. Neurochem. 2002, 81, 301–306.
  104. Wang, X.F.; Li, S.; Chou, A.P.; Bronstein, J.M. Inhibitory effects of pesticides on proteasome activity: Implication in Parkinson’s disease. Neurobiol. Dis. 2006, 23, 198–205.
  105. Betarbet, R.; Canet-Aviles, R.M.; Sherer, T.B.; Mastroberardino, P.G.; McLendon, C.; Kim, J.H.; Lund, S.; Na, H.M.; Taylor, G.; Bence, N.F.; et al. Intersecting pathways to neurodegeneration in Parkinson’s disease: Effects of the pesticide rotenone on DJ-1, alpha-synuclein, and the ubiquitin-proteasome system. Neurobiol. Dis. 2006, 22, 404–420.
  106. Chen, T.; Tan, J.; Wan, Z.; Zou, Y.; Afewerky, H.K.; Zhang, Z.; Zhang, T. Effects of Commonly Used Pesticides in China on the Mitochondria and Ubiquitin-Proteasome System in Parkinson’s Disease. Int. J. Mol. Sci. 2017, 18, 2507.
  107. Su, C.; Niu, P. Low doses of single or combined agrichemicals induces alpha-synuclein aggregation in nigrostriatal system of mice through inhibition of proteasomal and autophagic pathways. Int. J. Clin. Exp. Med. 2015, 8, 20508–20515.
  108. Chou, A.P.; Maidment, N.; Klintenberg, R.; Casida, J.E.; Li, S.; Fitzmaurice, A.G.; Fernagut, P.O.; Mortazavi, F.; Chesselet, M.F.; Bronstein, J.M. Ziram causes dopaminergic cell damage by inhibiting E1 ligase of the proteasome. J. Biol. Chem. 2008, 283, 34696–34703.
  109. Kim, J.J.; Kim, Y.S.; Kumar, V. Heavy metal toxicity: An update of chelating therapeutic strategies. J. Trace Elem. Med. Biol. Organ. Soc. Miner. Trace Elem. 2019, 54, 226–231.
  110. Kalita, J.; Kumar, V.; Misra, U.K. A Study on Apoptosis and Anti-apoptotic Status in Wilson Disease. Mol. Neurobiol. 2016, 53, 6659–6667.
  111. Chen, D.; Frezza, M.; Shakya, R.; Cui, Q.C.; Milacic, V.; Verani, C.N.; Dou, Q.P. Inhibition of the proteasome activity by gallium(III) complexes contributes to their anti prostate tumor effects. Cancer Res. 2007, 67, 9258–9265.
  112. Daniel, K.G.; Gupta, P.; Harbach, R.H.; Guida, W.C.; Dou, Q.P. Organic copper complexes as a new class of proteasome inhibitors and apoptosis inducers in human cancer cells. Biochem. Pharm. 2004, 67, 1139–1151.
  113. Araya, J.; Maruyama, M.; Inoue, A.; Fujita, T.; Kawahara, J.; Sassa, K.; Hayashi, R.; Kawagishi, Y.; Yamashita, N.; Sugiyama, E.; et al. Inhibition of proteasome activity is involved in cobalt-induced apoptosis of human alveolar macrophages. Am. J. Physiol. Lung Cell. Mol. Physiol. 2002, 283, L849–L858.
  114. Tam, L.M.; Wang, Y. Arsenic Exposure and Compromised Protein Quality Control. Chem. Res. Toxicol. 2020, 33, 1594–1604.
  115. Karri, V.; Schuhmacher, M.P.; Kumar, V. A systems toxicology approach to compare the heavy metal mixtures (Pb, As, MeHg) impact in neurodegenerative diseases. Food Chem. Toxicol. 2020, 139, 111257.
  116. Peters, A.; Dockery, D.W.; Muller, J.E.; Mittleman, M.A. Increased particulate air pollution and the triggering of myocardial infarction. Circulation 2001, 103, 2810–2815.
  117. Kipen, H.M.; Gandhi, S.; Rich, D.Q.; Ohman-Strickland, P.; Laumbach, R.; Fan, Z.H.; Chen, L.; Laskin, D.L.; Zhang, J.; Madura, K. Acute decreases in proteasome pathway activity after inhalation of fresh diesel exhaust or secondary organic aerosol. Environ. Health Perspect. 2011, 119, 658–663.
  118. Reinheckel, T.; Sitte, N.; Ullrich, O.; Kuckelkorn, U.; Davies, K.J.; Grune, T. Comparative resistance of the 20S and 26S proteasome to oxidative stress. Biochem. J. 1998, 335 Pt 3, 637–642.
  119. Van Rijt, S.H.; Keller, I.E.; John, G.; Kohse, K.; Yildirim, A.O.; Eickelberg, O.; Meiners, S. Acute cigarette smoke exposure impairs proteasome function in the lung. Am. J. Physiol. Lung Cell. Mol. Physiol. 2012, 303, L814–L823.
  120. Burns, C.J.; McIntosh, L.J.; Mink, P.J.; Jurek, A.M.; Li, A.A. Pesticide exposure and neurodevelopmental outcomes: Review of the epidemiologic and animal studies. J. Toxicol. Environ. Health Part B Crit. Rev. 2013, 16, 127–283.
  121. Baltazar, M.T.; Dinis-Oliveira, R.J.; de Lourdes Bastos, M.; Tsatsakis, A.M.; Duarte, J.A.; Carvalho, F. Pesticides exposure as etiological factors of Parkinson’s disease and other neurodegenerative diseases—A mechanistic approach. Toxicol. Lett. 2014, 230, 85–103.
  122. Moretto, A.; Colosio, C. Biochemical and toxicological evidence of neurological effects of pesticides: The example of Parkinson’s disease. Neurotoxicology 2011, 32, 383–391.
  123. Hansen, M.R.H.; Jørs, E.; Lander, F.; Condarco, G.; Debes, F.; Bustillos, N.T.; Schlünssen, V. Neurological Deficits After Long-term Pyrethroid Exposure. Environ. Health Insights 2017, 11, 1178630217700628.
  124. Chin-Chan, M.; Navarro-Yepes, J.; Quintanilla-Vega, B. Environmental pollutants as risk factors for neurodegenerative disorders: Alzheimer and Parkinson diseases. Front. Cell. Neurosci. 2015, 9, 124.
  125. Gunnarsson, L.G.; Bodin, L. Occupational Exposures and Neurodegenerative Diseases—A Systematic Literature Review and Meta-Analyses. Int. J. Environ. Res. Public Health 2019, 16, 337.
  126. Hossain, M.M.; Richardson, J.R. Mechanism of pyrethroid pesticide-induced apoptosis: Role of calpain and the ER stress pathway. Toxicol. Sci. 2011, 122, 512–525.
  127. Xiao, X.; Qi, W.; Clark, J.M.; Park, Y. Permethrin potentiates adipogenesis via intracellular calcium and endoplasmic reticulum stress-mediated mechanisms in 3T3-L1 adipocytes. Food Chem. Toxicol. 2017, 109, 123–129.
  128. Reyna, L.; Flores-Martin, J.; Ridano, M.E.; Panzetta-Dutari, G.M.; Genti-Raimondi, S. Chlorpyrifos induces endoplasmic reticulum stress in JEG-3 cells. Toxicol. In Vitro 2017, 40, 88–93.
  129. Simard, J.C.; Durocher, I.; Girard, D. Silver nanoparticles induce irremediable endoplasmic reticulum stress leading to unfolded protein response dependent apoptosis in breast cancer cells. Apoptosis 2016, 21, 1279–1290.
  130. Rajakumar, S.; Vijayakumar, R.; Abhishek, A.; Selvam, G.S.; Nachiappan, V. Loss of ERAD bridging factor UBX2 modulates lipid metabolism and leads to ER stress-associated apoptosis during cadmium toxicity in Saccharomyces cerevisiae. Curr. Genet. 2020, 66, 1003–1017.
  131. Wang, X.; Robbins, J. Heart failure and protein quality control. Circ. Res. 2006, 99, 1315–1328.
  132. Wang, X.; Pattison, J.S.; Su, H. Posttranslational modification and quality control. Circ. Res. 2013, 112, 367–381.
  133. Miller, W.H., Jr.; Schipper, H.M.; Lee, J.S.; Singer, J.; Waxman, S. Mechanisms of action of arsenic trioxide. Cancer Res. 2002, 62, 3893–3903.
  134. Goussetis, D.J.; Altman, J.K.; Glaser, H.; McNeer, J.L.; Tallman, M.S.; Platanias, L.C. Autophagy is a critical mechanism for the induction of the antileukemic effects of arsenic trioxide. J. Biol. Chem. 2010, 285, 29989–29997.
  135. Kanzawa, T.; Zhang, L.; Xiao, L.; Germano, I.M.; Kondo, Y.; Kondo, S. Arsenic trioxide induces autophagic cell death in malignant glioma cells by upregulation of mitochondrial cell death protein BNIP3. Oncogene 2005, 24, 980–991.
  136. Yang, Y.P.; Liang, Z.Q.; Gao, B.; Jia, Y.L.; Qin, Z.H. Dynamic effects of autophagy on arsenic trioxide-induced death of human leukemia cell line HL60 cells. Acta Pharmacol. Sin. 2008, 29, 123–134.
  137. Isakson, P.; Bjoras, M.; Boe, S.O.; Simonsen, A. Autophagy contributes to therapy-induced degradation of the PML/RARA oncoprotein. Blood 2010, 116, 2324–2331.
  138. Son, Y.O.; Wang, X.; Hitron, J.A.; Zhang, Z.; Cheng, S.; Budhraja, A.; Ding, S.; Lee, J.C.; Shi, X. Cadmium induces autophagy through ROS-dependent activation of the LKB1-AMPK signaling in skin epidermal cells. Toxicol. Appl. Pharmacol. 2011, 255, 287–296.
  139. Park, J.H.; Lee, J.E.; Shin, I.C.; Koh, H.C. Autophagy regulates chlorpyrifos-induced apoptosis in SH-SY5Y cells. Toxicol. Appl. Pharmacol. 2013, 268, 55–67.
  140. Corcelle, E.; Nebout, M.; Bekri, S.; Gauthier, N.; Hofman, P.; Poujeol, P.; Fenichel, P.; Mograbi, B. Disruption of autophagy at the maturation step by the carcinogen lindane is associated with the sustained mitogen-activated protein kinase/extracellular signal-regulated kinase activity. Cancer Res. 2006, 66, 6861–6870.
  141. Zucchini-Pascal, N.; de Sousa, G.; Rahmani, R. Lindane and cell death: At the crossroads between apoptosis, necrosis and autophagy. Toxicology 2009, 256, 32–41.
  142. Huang, H.; Zhu, J.; Li, Y.; Zhang, L.; Gu, J.; Xie, Q.; Jin, H.; Che, X.; Li, J.; Huang, C.; et al. Upregulation of SQSTM1/p62 contributes to nickel-induced malignant transformation of human bronchial epithelial cells. Autophagy 2016, 12, 1687–1703.
  143. Gonzalez-Polo, R.A.; Niso-Santano, M.; Ortiz-Ortiz, M.A.; Gomez-Martin, A.; Moran, J.M.; Garcia-Rubio, L.; Francisco-Morcillo, J.; Zaragoza, C.; Soler, G.; Fuentes, J.M. Inhibition of paraquat-induced autophagy accelerates the apoptotic cell death in neuroblastoma SH-SY5Y cells. Toxicol. Sci. 2007, 97, 448–458.
  144. Niso-Santano, M.; Bravo-San Pedro, J.M.; Gomez-Sanchez, R.; Climent, V.; Soler, G.; Fuentes, J.M.; Gonzalez-Polo, R.A. ASK1 overexpression accelerates paraquat-induced autophagy via endoplasmic reticulum stress. Toxicol. Sci. 2011, 119, 156–168.
  145. Xiong, N.; Jia, M.; Chen, C.; Xiong, J.; Zhang, Z.; Huang, J.; Hou, L.; Yang, H.; Cao, X.; Liang, Z.; et al. Potential autophagy enhancers attenuate rotenone-induced toxicity in SH-SY5Y. Neuroscience 2011, 199, 292–302.
  146. Gui, Y.X.; Fan, X.N.; Wang, H.M.; Wang, G.; Chen, S.D. Glyphosate induced cell death through apoptotic and autophagic mechanisms. Neurotoxicol. Teratol. 2012, 34, 344–349.
More
Information
Contributor MDPI registered users' name will be linked to their SciProfiles pages. To register with us, please refer to https://encyclopedia.pub/register :
View Times: 3.8K
Revisions: 2 times (View History)
Update Date: 18 Mar 2021
1000/1000
ScholarVision Creations