1. Please check and comment entries here.
Table of Contents

    Topic review

    LGI1 Gene

    View times: 16
    Submitted by: Dean Liu
    (This entry belongs to Entry Collection "MedlinePlus ")

    Definition

    Leucine rich glioma inactivated 1

    1. Introduction

    The LGI1 gene provides instructions for making a protein called leucine-rich glioma inactivated 1 (Lgi1) or epitempin. This protein is found primarily in nerve cells (neurons) in the brain, including a part of the brain called the lateral temporal lobe. The temporal lobe of the brain is involved in hearing, speech, memory, and emotion.

    Although researchers have proposed several functions for epitempin, its precise role in the brain remains uncertain. This protein is probably involved in normal brain development.

    Some studies have suggested that epitempin plays a role in the normal function of potassium channels in neurons. These channels are embedded in the cell membrane, where they transport charged potassium atoms (potassium ions) out of neurons. Potassium channels are critical for normal electrical signaling in these cells. Other studies have found that epitempin is transported (secreted) out of neurons. The function of this protein outside cells is unclear.

    Epitempin may also help regulate the communication between neurons. Researchers have determined that epitempin attaches (binds) to a receptor protein called ADAM22 on the surface of neurons. Together, these proteins help control the release of certain brain chemicals called neurotransmitters. These chemicals allow neighboring neurons to communicate with each other, which is how signals are relayed throughout the brain.

    2. Health Conditions Related to Genetic Changes

    2.1. Autosomal Dominant Partial Epilepsy with Auditory Features

    At least 22 mutations in the LGI1 gene have been identified in people with autosomal dominant partial epilepsy with auditory features (ADPEAF). Some LGI1 mutations change a single protein building block (amino acid) in the epitempin protein, which alters the protein's structure. Other mutations lead to the production of an abnormally short, nonfunctional version of the protein. Researchers suspect that the altered protein is unable to be secreted, which would leave it trapped within cells and unable to perform its usual functions. Although LGI1 mutations disrupt the function of epitempin, it is unclear how the altered protein leads to seizure activity in the brain.

    2.2. Cancers

    When the LGI1 gene was first described, researchers believed that it might play a role in the growth and progression of brain tumors called gliomas. Epitempin was thought to act as a tumor suppressor, which is a protein that keeps cells from growing and dividing too fast or in an uncontrolled way. More recent studies have called into question the role of epitempin in cancerous tumors. Because no LGI1 mutations have been identified in gliomas and people with ADPEAF do not appear to have a greatly increased risk of these tumors, it now appears unlikely that epitempin functions as a tumor suppressor.

    3. Other Names for This Gene

    • EPITEMPIN

    • Epitempin 1

    • EPT

    • ETL1

    • IB1099

    • Leucine-Rich Glioma-Inactivated Protein 1

    • leucine-rich, glioma inactivated 1

    • LGI1_HUMAN

    This entry is adapted from https://medlineplus.gov/genetics/gene/lgi1

    References

    1. Chernova OB, Somerville RP, Cowell JK. A novel gene, LGI1, from 10q24 isrearranged and downregulated in malignant brain tumors. Oncogene. 1998 Dec3;17(22):2873-81.
    2. Fukata Y, Adesnik H, Iwanaga T, Bredt DS, Nicoll RA, Fukata M.Epilepsy-related ligand/receptor complex LGI1 and ADAM22 regulate synaptictransmission. Science. 2006 Sep 22;313(5794):1792-5.
    3. Furlan S, Roncaroli F, Forner F, Vitiello L, Calabria E, Piquer-Sirerol S,Valle G, Perez-Tur J, Michelucci R, Nobile C. The LGI1/epitempin gene encodes twoprotein isoforms differentially expressed in human brain. J Neurochem. 2006Aug;98(3):985-91.
    4. Gu W, Brodtkorb E, Piepoli T, Finocchiaro G, Steinlein OK. LGI1: a geneinvolved in epileptogenesis and glioma progression? Neurogenetics. 2005May;6(2):59-66.
    5. Gu W, Brodtkorb E, Steinlein OK. LGI1 is mutated in familial temporal lobeepilepsy characterized by aphasic seizures. Ann Neurol. 2002 Sep;52(3):364-7.
    6. Kalachikov S, Evgrafov O, Ross B, Winawer M, Barker-Cummings C, MartinelliBoneschi F, Choi C, Morozov P, Das K, Teplitskaya E, Yu A, Cayanis E,Penchaszadeh G, Kottmann AH, Pedley TA, Hauser WA, Ottman R, Gilliam TC.Mutations in LGI1 cause autosomal-dominant partial epilepsy with auditoryfeatures. Nat Genet. 2002 Mar;30(3):335-41.
    7. Morante-Redolat JM, Gorostidi-Pagola A, Piquer-Sirerol S, Sáenz A, Poza JJ,Galán J, Gesk S, Sarafidou T, Mautner VF, Binelli S, Staub E, Hinzmann B, French L, Prud'homme JF, Passarelli D, Scannapieco P, Tassinari CA, Avanzini G,Martí-Massó JF, Kluwe L, Deloukas P, Moschonas NK, Michelucci R, Siebert R,Nobile C, Pérez-Tur J, López de Munain A. Mutations in the LGI1/Epitempin gene on10q24 cause autosomal dominant lateral temporal epilepsy. Hum Mol Genet. 2002 May1;11(9):1119-28.
    8. Ottman R, Winawer MR, Kalachikov S, Barker-Cummings C, Gilliam TC, Pedley TA, Hauser WA. LGI1 mutations in autosomal dominant partial epilepsy with auditoryfeatures. Neurology. 2004 Apr 13;62(7):1120-6.
    9. Piepoli T, Jakupoglu C, Gu W, Lualdi E, Suarez-Merino B, Poliani PL, Cattaneo MG, Ortino B, Goplen D, Wang J, Mola R, Inverardi F, Frassoni C, Bjerkvig R,Steinlein O, Vicentini LM, Brüstle O, Finocchiaro G. Expression studies ingliomas and glial cells do not support a tumor suppressor role for LGI1. NeuroOncol. 2006 Apr;8(2):96-108.
    10. Schulte U, Thumfart JO, Klöcker N, Sailer CA, Bildl W, Biniossek M, Dehn D,Deller T, Eble S, Abbass K, Wangler T, Knaus HG, Fakler B. The epilepsy-linkedLgi1 protein assembles into presynaptic Kv1 channels and inhibits inactivation byKvbeta1. Neuron. 2006 Mar 2;49(5):697-706.
    11. Senechal KR, Thaller C, Noebels JL. ADPEAF mutations reduce levels of secretedLGI1, a putative tumor suppressor protein linked to epilepsy. Hum Mol Genet. 2005Jun 15;14(12):1613-20.
    12. Sirerol-Piquer MS, Ayerdi-Izquierdo A, Morante-Redolat JM, Herranz-Pérez V,Favell K, Barker PA, Pérez-Tur J. The epilepsy gene LGI1 encodes a secretedglycoprotein that binds to the cell surface. Hum Mol Genet. 2006 Dec1;15(23):3436-45.
    More

    Keywords