Gamma-sarcoglycan is a protein that in humans is encoded by the SGCGgene.[1][2] The α to δ-sarcoglycans are expressed predominantly (β) or exclusively (α, γ and δ) in striated muscle.[3] A mutation in any of the sarcoglycan genes may lead to a secondary deficiency of the other sarcoglycan proteins, presumably due to destabilisation of the sarcoglycan complex.[4] The disease-causing mutations in the α to δ genes cause disruptions within the dystrophin-associated protein (DAP) complex in the muscle cell membrane.[5] The transmembrane components of the DAP complex link the cytoskeleton to the extracellular matrix in adult muscle fibres,[6] and are essential for the preservation of the integrity of the muscle cell membrane.[7]
Gamma-sarcoglycan is one of several sarcolemmal transmembrane glycoproteins that interact with dystrophin, probably to provide a link between the membrane associated cytoskeleton and the extracellular matrix. Defects in the protein can lead to early onset autosomal recessive muscular dystrophy, in particular limb-girdle muscular dystrophy, type 2C (LGMD2C).[2]
Structure
Gene
Human SGCG gene maps to chromosome 13 at q12, spans over 100 kb of DNA and includes 8 exons.[8]
Sarcoglycanopathies are autosomal recessive limb girdle muscular dystrophies (LGMDs) caused by mutations in any of the four sarcoglycan genes: α (LGMD2D), β (LGMD2E), γ (LGMD2C) and δ (LGMD2F).[3] Severe childhood autosomal recessive muscular dystrophy (SCARMD) is a progressive muscle-wasting disorder that segregates with microsatellite markers at γ-sarcoglycan gene. Mutations in the γ-sarcoglycan gene were first described in the Maghreb countries of North Africa,[9] where γ-sarcoglycanopathy has a higher than usual incidence. One common mutation, Δ-521T, which causes a severe phenotype, occurs both in the Maghreb population and in other countries.[8] A Cys283Tyr mutation has been identified in the Gypsy population causing a severe phenotype and a Leu193Ser mutation which causes a mild phenotype.[1][10]
↑ 3.03.1Noguchi S, McNally EM, Ben Othmane K, Hagiwara Y, Mizuno Y, Yoshida M, Yamamoto H, Bönnemann CG, Gussoni E, Denton PH, Kyriakides T, Middleton L, Hentati F, Ben Hamida M, Nonaka I, Vance JM, Kunkel LM, Ozawa E (Nov 1995). "Mutations in the dystrophin-associated protein gamma-sarcoglycan in chromosome 13 muscular dystrophy". Science. 270 (5237): 819–22. doi:10.1126/science.270.5237.819. PMID7481775.
↑ 4.04.1Nowak KJ, Walsh P, Jacob RL, Johnsen RD, Peverall J, McNally EM, Wilton SD, Kakulas BA, Laing NG (Feb 2000). "Severe gamma-sarcoglycanopathy caused by a novel missense mutation and a large deletion". Neuromuscular Disorders. 10 (2): 100–7. doi:10.1016/s0960-8966(99)00063-2. PMID10714584.
↑Vainzof M, Passos-Bueno MR, Canovas M, Moreira ES, Pavanello RC, Marie SK, Anderson LV, Bonnemann CG, McNally EM, Nigro V, Kunkel LM, Zatz M (Dec 1996). "The sarcoglycan complex in the six autosomal recessive limb-girdle muscular dystrophies". Human Molecular Genetics. 5 (12): 1963–9. doi:10.1093/hmg/5.12.1963. PMID8968750.
↑Ettinger AJ, Feng G, Sanes JR (Dec 1997). "epsilon-Sarcoglycan, a broadly expressed homologue of the gene mutated in limb-girdle muscular dystrophy 2D". The Journal of Biological Chemistry. 272 (51): 32534–8. doi:10.1074/jbc.272.51.32534. PMID9405466.
↑Holt KH, Campbell KP (Dec 1998). "Assembly of the sarcoglycan complex. Insights for muscular dystrophy". The Journal of Biological Chemistry. 273 (52): 34667–70. doi:10.1074/jbc.273.52.34667. PMID9856984.
↑ 8.08.1McNally EM, Duggan D, Gorospe JR, Bönnemann CG, Fanin M, Pegoraro E, Lidov HG, Noguchi S, Ozawa E, Finkel RS, Cruse RP, Angelini C, Kunkel LM, Hoffman EP (Nov 1996). "Mutations that disrupt the carboxyl-terminus of gamma-sarcoglycan cause muscular dystrophy". Human Molecular Genetics. 5 (11): 1841–7. doi:10.1093/hmg/5.11.1841. PMID8923014.
↑van der Kooi AJ, de Visser M, van Meegen M, Ginjaar HB, van Essen AJ, Jennekens FG, Jongen PJ, Leschot NJ, Bolhuis PA (Jun 1998). "A novel gamma-sarcoglycan mutation causing childhood onset, slowly progressive limb girdle muscular dystrophy". Neuromuscular Disorders. 8 (5): 305–8. doi:10.1016/s0960-8966(98)00040-6. PMID9673983.
↑Guyon JR, Kudryashova E, Potts A, Dalkilic I, Brosius MA, Thompson TG, Beckmann JS, Kunkel LM, Spencer MJ (October 2003). "Calpain 3 cleaves filamin C and regulates its ability to interact with gamma- and delta-sarcoglycans". Muscle Nerve. 28 (4): 472–83. doi:10.1002/mus.10465. PMID14506720.
Noguchi S, McNally EM, Ben Othmane K, Hagiwara Y, Mizuno Y, Yoshida M, Yamamoto H, Bönnemann CG, Gussoni E, Denton PH, Kyriakides T, Middleton L, Hentati F, Ben Hamida M, Nonaka I, Vance JM, Kunkel LM, Ozawa E (1995). "Mutations in the dystrophin-associated protein gamma-sarcoglycan in chromosome 13 muscular dystrophy". Science. 270 (5237): 819–22. doi:10.1126/science.270.5237.819. PMID7481775.
Nowak KJ, Walsh P, Jacob RL, Johnsen RD, Peverall J, McNally EM, Wilton SD, Kakulas BA, Laing NG (2000). "Severe gamma-sarcoglycanopathy caused by a novel missense mutation and a large deletion". Neuromuscul. Disord. 10 (2): 100–7. doi:10.1016/S0960-8966(99)00063-2. PMID10714584.
Yoshida M, Hama H, Ishikawa-Sakurai M, Imamura M, Mizuno Y, Araishi K, Wakabayashi-Takai E, Noguchi S, Sasaoka T, Ozawa E (2000). "Biochemical evidence for association of dystrobrevin with the sarcoglycan-sarcospan complex as a basis for understanding sarcoglycanopathy". Hum. Mol. Genet. 9 (7): 1033–40. doi:10.1093/hmg/9.7.1033. PMID10767327.
Crosbie RH, Lim LE, Moore SA, Hirano M, Hays AP, Maybaum SW, Collin H, Dovico SA, Stolle CA, Fardeau M, Tomé FM, Campbell KP (2000). "Molecular and genetic characterization of sarcospan: insights into sarcoglycan-sarcospan interactions". Hum. Mol. Genet. 9 (13): 2019–27. doi:10.1093/hmg/9.13.2019. PMID10942431.
Barresi R, Moore SA, Stolle CA, Mendell JR, Campbell KP (2001). "Expression of gamma -sarcoglycan in smooth muscle and its interaction with the smooth muscle sarcoglycan-sarcospan complex". J. Biol. Chem. 275 (49): 38554–60. doi:10.1074/jbc.M007799200. PMID10993904.
Wheeler MT, Zarnegar S, McNally EM (2003). "Zeta-sarcoglycan, a novel component of the sarcoglycan complex, is reduced in muscular dystrophy". Hum. Mol. Genet. 11 (18): 2147–54. doi:10.1093/hmg/11.18.2147. PMID12189167.
Vermeer S, Verrips A, Willemsen MA, ter Laak HJ, Ginjaar IB, Hamel BC (2004). "Novel mutations in three patients with LGMD2C with phenotypic differences". Pediatr. Neurol. 30 (4): 291–4. doi:10.1016/j.pediatrneurol.2003.11.006. PMID15087111.
White SJ, Uitte de Willige S, Verbove D, Politano L, Ginjaar I, Breuning MH, den Dunnen JT (2006). "Sarcoglycanopathies and the risk of undetected deletion alleles in diagnosis". Hum. Mutat. 26 (1): 59. doi:10.1002/humu.9347. PMID15954112.
Duncan DR, Kang PB, Rabbat JC, Briggs CE, Lidov HG, Darras BT, Kunkel LM (2006). "A novel mutation in two families with limb-girdle muscular dystrophy type 2C". Neurology. 67 (1): 167–9. doi:10.1212/01.wnl.0000223600.78363.dd. PMID16832103.