Sarcoglycan
Encyclopedia
The sarcoglycans are a family of transmembrane protein
s (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 several muscle-specific, transmembrane proteins (alpha-, beta-, gamma-, delta- 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
.
Transmembrane protein
A transmembrane protein is a protein that goes from one side of a membrane through to the other side of the membrane. Many TPs function as gateways or "loading docks" to deny or permit the transport of specific substances across the biological membrane, to get into the cell, or out of the cell as...
s (α, β, γ, δ or ε) involved in the protein complex
Protein complex
A multiprotein complex is a group of two or more associated polypeptide chains. If the different polypeptide chains contain different protein domain, the resulting multiprotein complex can have multiple catalytic functions...
responsible for connecting the muscle fibre cytoskeleton
Cytoskeleton
The cytoskeleton is a cellular "scaffolding" or "skeleton" contained within a cell's cytoplasm and is made out of protein. The cytoskeleton is present in all cells; it was once thought to be unique to eukaryotes, but recent research has identified the prokaryotic cytoskeleton...
to the extracellular matrix
Extracellular matrix
In biology, the extracellular matrix is the extracellular part of animal tissue that usually provides structural support to the animal cells in addition to performing various other important functions. The extracellular matrix is the defining feature of connective tissue in animals.Extracellular...
, preventing damage to the muscle fibre sarcolemma
Sarcolemma
The sarcolemma is the cell membrane of a muscle cell . It consists of a true cell membrane, called the plasma membrane, and an outer coat made up of a thin layer of polysaccharide material that contains numerous thin collagen fibrils...
through shearing forces.
The dystrophin
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...
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 several muscle-specific, transmembrane proteins (alpha-, beta-, gamma-, delta- 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
Sarcoglycanopathies
The sarcoglycanopathies are a collection of diseases resulting from mutations in any of the four sarcoglycan genes, α, β, γ or δ.The four sarcoglycanopathies are : α-sarcoglycanopathy, LGMD2D; β-sarcoglycanopathy, LGMD2E; γ-sarcoglycanopathy, LGMD2C; δ-sarcoglycanopathy, LGMD2F...
. Mutations in the α, β, γ or δ genes (not ε) encoding these proteins can lead to the associated limb-girdle muscular dystrophy
Limb-girdle muscular dystrophy
Limb-girdle muscular dystrophy or Erb's muscular dystrophy is an autosomal class of muscular dystrophy that is similar but distinct from Duchenne muscular dystrophy and Becker's muscular dystrophy...
.