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Sarcoglycan
The sarcoglycans are a family of transmembrane proteins (α, β, γ, δ or ε) involved in the protein complex responsible for connecting the muscle fibre cytoskeleton to the extracellular matrix, preventing damage to the muscle fibre sarcolemma through shearing forces. The dystrophin glycoprotein complex (DGC) is a membrane-spanning complex that links the interior cytoskeleton to the extracellular matrix in muscle. The sarcoglycan complex is a subcomplex within the DGC and is composed of six muscle-specific, transmembrane proteins (alpha-, beta-, gamma-, delta-, epsilon-,and zeta-sarcoglycan). The sarcoglycans are asparagine-linked glycosylated proteins with single transmembrane domains. The disorders caused by the mutations of the sarcoglycans are called sarcoglycanopathies. Mutations in the α, β, γ or δ genes (not ε) encoding these proteins can lead to the associated limb-girdle muscular dystrophy. Genes * SGCA * SGCB * SGCD * SGCE * SGCG Gamma-sarcoglycan is a prote ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SGCG
Gamma-sarcoglycan is a protein that in humans is encoded by the ''SGCG'' gene. The α to δ-sarcoglycans are expressed predominantly (β) or exclusively (α, γ and δ) in striated muscle. 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. The disease-causing mutations in the α to δ genes cause disruptions within the dystrophin-associated protein (DAP) complex in the muscle cell membrane. The transmembrane components of the DAP complex link the cytoskeleton to the extracellular matrix in adult muscle fibres, and are essential for the preservation of the integrity of the muscle cell membrane. Function 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SGCB
Beta-sarcoglycan is a protein that in humans is encoded by the ''SGCB'' gene. The dystrophin-glycoprotein complex (DGC) is a multisubunit protein complex that spans the sarcolemma and provides structural linkage between the subsarcolemmal cytoskeleton and the extracellular matrix of muscle cells. There are 3 main subcomplexes of the DGC: the cytoplasmic proteins dystrophin (DMD; MIM 300377) and syntrophin (SNTA1; MIM 601017), the alpha- and beta-dystroglycans (see MIM 128239), and the sarcoglycans (see, e.g., SGCA; MIM 600119) (Crosbie et al., 2000). upplied by OMIMref name="entrez" /> References Further reading * * * * * * * * * * * * * * * * * * * External links * LOVD The Leiden Open Variation Database (LOVD) is a free, flexible web-based open source database developed in the Leiden University Medical Center in the Netherlands, designed to collect and display variants in the DNA sequence. The focus of an LOVD i ... mutation databaseSGCB {{gene-4-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delta-sarcoglycan
Delta-sarcoglycan is a protein that in humans is encoded by the ''SGCD'' gene. Function The protein encoded by this gene is one of the four known components of the sarcoglycan complex, which is a subcomplex of the dystrophin-glycoprotein complex (DGC). DGC forms a link between the F-actin cytoskeleton and the extracellular matrix. This protein is expressed most abundantly in skeletal and cardiac muscle. The mutations in this gene have been associated with autosomal recessive limb-girdle muscular dystrophy and dilated cardiomyopathy. Alternatively spliced transcript variants encoding distinct isoforms have been observed. In melanocytic cells SGCD gene expression may be regulated by MITF. Interactions SGCD has been shown to interact with FLNC. References Further reading * * * * * * * * * * * * * * * * External links * LOVD The Leiden Open Variation Database (LOVD) is a free, flexible web-based open source database developed in the Leiden Universit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SGCE
Epsilon-sarcoglycan is a protein that in humans is encoded by the ''SGCE'' gene. The SGCE gene encodes the epsilon member of the sarcoglycan family, transmembrane components of the dystrophin-glycoprotein complex, which links the cytoskeleton to the extracellular matrix. upplied by OMIMref name="entrez"/> See also * Myoclonic dystonia References Further reading * * * * * * * * * * * * * * * * * * External links GeneReviews/NIH/NCBI/UW entry on Myoclonus-Dystonia* LOVD The Leiden Open Variation Database (LOVD) is a free, flexible web-based open source database developed in the Leiden University Medical Center in the Netherlands, designed to collect and display variants in the DNA sequence. The focus of an LOVD i ... mutation databaseSGCE {{gene-7-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SGCA
Alpha-sarcoglycan is a protein that in humans is encoded by the ''SGCA'' gene. Function The dystrophin-glycoprotein complex (DGC) comprises a group of proteins that are critical to the stability of muscle fiber membranes and to the linking of the actin cytoskeleton to the extracellular matrix. Components of the DGC include dystrophin (MIM 300377), which is deficient in Duchenne muscular dystrophy (DMD; MIM 310200); syntrophins (e.g., MIM 600026); dystroglycans (MIM 128239); and sarcoglycans, such as adhalin, a 50-kD transmembrane protein (Roberds et al., 1993). upplied by OMIMref name="entrez"/> Interactions SGCA has been shown to interact with Biglycan. References Further reading * * * * * * * * * * * * * * * * * External links *LOVD The Leiden Open Variation Database (LOVD) is a free, flexible web-based open source database developed in the Leiden University Medical Center in the Netherlands, designed to collect and display variants in the DNA sequence. The focus of an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sarcoglycanopathies
The sarcoglycanopathies are a collection of diseases resulting from mutations in any of the five sarcoglycan genes: α, β, γ, δ or ε. The five sarcoglycanopathies are: α-sarcoglycanopathy, LGMD2D; β-sarcoglycanopathy, LGMD2E; γ-sarcoglycanopathy, LGMD2C; δ-sarcoglycanopathy, LGMD2F and ε-sarcoglycanopathy, myoclonic dystonia. The four different sarcoglycan genes encode proteins that form a tetrameric complex at the muscle cell plasma membrane. This complex stabilizes the association of dystrophin with the dystroglycans and contributes to the stability of the plasma membrane cytoskeleton. The four sarcoglycan genes are related to each other structurally and functionally, but each has a distinct chromosome location. In outbred populations, the relative frequency of mutations in the four genes is alpha >> beta >> gamma >> delta in an 8:4:2:1 ratio. No common mutations have been identified in outbred populations except the R77C mutation, which accounts for up to one-third of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SGCZ
Sarcoglycan zeta also known as SGCZ is a protein which in humans is encoded by the ''SGCZ'' gene. Function The zeta-sarcoglycan gene measures over 465 kb and localizes to 8p22. This protein is part of the sarcoglycan complex, a group of 6 proteins. The sarcoglycans are all N-glycosylated transmembrane proteins with a short intra-cellular domain, a single transmembrane region and a large extra-cellular domain containing a carboxyl-terminal cluster with several conserved cysteine residues. The sarcoglycan complex is part of the dystrophin-associated glycoprotein complex (DGC), which bridges the inner cytoskeleton and the extracellular matrix. Clinical significance Zeta-sarcoglycan is reduced in mouse models of muscular dystrophy and SGCZ is found as a component of the vascular smooth muscle sarcoglycan complex. Hence SGCZ may be important in the pathogenesis of muscular dystrophy. References External links * LOVD The Leiden Open Variation Database (LOVD) is a free, f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dystrophin
Dystrophin is a rod-shaped cytoplasmic protein, and a vital part of a protein complex that connects the cytoskeleton of a muscle fiber to the surrounding extracellular matrix through the cell membrane. This complex is variously known as the costamere or the dystrophin-associated protein complex (DAPC). Many muscle proteins, such as α-dystrobrevin, syncoilin, synemin, sarcoglycan, dystroglycan, and sarcospan, colocalize with dystrophin at the costamere. It has a molecular weight of 427 kDa Dystrophin is coded for by the ''DMD'' gene – the largest known human gene, covering 2.4 megabases (0.08% of the human genome) at locus Xp21. The primary transcript in muscle measures about 2,100 kilobases and takes 16 hours to transcribe; the mature mRNA measures 14.0 kilobases. The 79-exon muscle transcript codes for a protein of 3685 amino acid residues. Spontaneous or inherited mutations in the dystrophin gene can cause different forms of muscular dystrophy, a disease characterized by p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmembrane Protein
A transmembrane protein (TP) is a type of integral membrane protein that spans the entirety of the cell membrane. Many transmembrane proteins function as gateways to permit the transport of specific substances across the membrane. They frequently undergo significant conformational changes to move a substance through the membrane. They are usually highly hydrophobic and aggregate and precipitate in water. They require detergents or nonpolar solvents for extraction, although some of them (beta-barrels) can be also extracted using denaturing agents. The peptide sequence that spans the membrane, or the transmembrane segment, is largely hydrophobic and can be visualized using the hydropathy plot. Depending on the number of transmembrane segments, transmembrane proteins can be classified as single-span (or bitopic) or multi-span (polytopic). Some other integral membrane proteins are called monotopic, meaning that they are also permanently attached to the membrane, but do not pass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Complex
A protein complex or multiprotein complex is a group of two or more associated polypeptide chains. Protein complexes are distinct from multienzyme complexes, in which multiple catalytic domains are found in a single polypeptide chain. Protein complexes are a form of quaternary structure. Proteins in a protein complex are linked by non-covalent protein–protein interactions. These complexes are a cornerstone of many (if not most) biological processes. The cell is seen to be composed of modular supramolecular complexes, each of which performs an independent, discrete biological function. Through proximity, the speed and selectivity of binding interactions between enzymatic complex and substrates can be vastly improved, leading to higher cellular efficiency. Many of the techniques used to enter cells and isolate proteins are inherently disruptive to such large complexes, complicating the task of determining the components of a complex. Examples of protein complexes include the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytoskeleton
The cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all cells, including those of bacteria and archaea. In eukaryotes, it extends from the cell nucleus to the cell membrane and is composed of similar proteins in the various organisms. It is composed of three main components, microfilaments, intermediate filaments and microtubules, and these are all capable of rapid growth or disassembly dependent on the cell's requirements. A multitude of functions can be performed by the cytoskeleton. Its primary function is to give the cell its shape and mechanical resistance to deformation, and through association with extracellular connective tissue and other cells it stabilizes entire tissues. The cytoskeleton can also contract, thereby deforming the cell and the cell's environment and allowing cells to migrate. Moreover, it is involved in many cell signaling pathways and in the uptake of extracellular material ( endocytosis), the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Extracellular Matrix
In biology, the extracellular matrix (ECM), also called intercellular matrix, is a three-dimensional network consisting of extracellular macromolecules and minerals, such as collagen, enzymes, glycoproteins and hydroxyapatite that provide structural and biochemical support to surrounding cells. Because multicellularity evolved independently in different multicellular lineages, the composition of ECM varies between multicellular structures; however, cell adhesion, cell-to-cell communication and differentiation are common functions of the ECM. The animal extracellular matrix includes the interstitial matrix and the basement membrane. Interstitial matrix is present between various animal cells (i.e., in the intercellular spaces). Gels of polysaccharides and fibrous proteins fill the Interstitial fluid, interstitial space and act as a compression buffer against the stress placed on the ECM. Basement membranes are sheet-like depositions of ECM on which various epithelial cells rest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
