What is the dystroglycan complex?
The dystroglycan complex contains the transmembrane protein β-dystroglycan and its interacting extracellular mucin-like protein α-dystroglycan. In skeletal muscle fibers, the dystroglycan complex plays an important structural role by linking the cytoskeletal protein dystrophin to laminin in the extracellular matrix.
Is Dystroglycan a protein?
The α-dystroglycan is 156 kDa in size; it is an extracellular protein that binds noncovalently to β-dystroglycan in the dystroglycan complex, on the one hand, and to laminin and/or agrin in the extracellular matrix, on the other. β-Dystroglycan is a 43 kDa glycoprotein and is an integral membrane protein.
How does dystrophin cause muscular dystrophy?
Mutations in the DMD gene alter the structure or function of dystrophin or prevent any functional dystrophin from being produced. Muscle cells without enough of this protein become damaged as muscles repeatedly contract and relax with use.
How does dystrophin affect muscle contraction?
The dystrophin complex has been hypothesized to act as a membrane stabilizer during muscle contraction to prevent contraction-induced damage (48, 124). In addition to its structural role, dystrophin complex is also thought to mediate cellular signaling such as mechanical force transduction and cell adhesion.
What is β Dystroglycan?
β-Dystroglycan is a 43 kDa glycoprotein and is an integral membrane protein. Numerous other proteins associate with the dystroglycans and together they form a large structure called the dystroglycan complex.
What is alpha dystroglycan?
α-Dystroglycan is a peripheral membrane component of the dystrophin–glycoprotein complex (DGC) found in muscle, nerve, heart, and brain. This protein binds to merosin in extracellular matrix bridging it to the cytoskeleton molecules that include dystrophin and actin.
What is β dystroglycan?
Which gene causes DMD?
DMD is caused by mutations of the DMD gene located on the short arm (p) of the X chromosome (Xp21. 2). Chromosomes, which are present in the nucleus of human cells, carry the genetic information for each individual.
What is the pathophysiology of DMD?
Duchenne muscular dystrophy (DMD) is a genetic muscle disorder caused by mutations in the Dmd gene resulting in the loss of the protein dystrophin. Patients do not only experience skeletal muscle degeneration, but also develop severe cardiomyopathy by their second decade, one of the main causes of death.
What is dystrophin responsible for?
In skeletal and cardiac muscles, dystrophin is part of a group of proteins (a protein complex) that work together to strengthen muscle fibers and protect them from injury as muscles contract and relax.
Where is Pikachurin found?
synaptic cleft
Pikachurin is the most recently identified dystroglycan ligand protein and is localized in the synaptic cleft in the photoreceptor ribbon synapse.
What is Merosin?
Merosin collectively is a term that refers to a group of laminins that share the alpha2 subunit encoded by the LAMA2 gene. Laminins are a family of high molecular weight glycoproteins that function as extracellular matrix components of the structural basement membrane.
What is desmin physiology?
Abstract. Desmin is the intermediate filament (IF) protein occurring exclusively in muscle and endothelial cells. There are other IF proteins in muscle such as nestin, peripherin, and vimentin, besides the ubiquitous lamins, but they are not unique to muscle.
Is alpha dystroglycan linker protein?
The dystroglycan complex is widely expressed in many tissues4 and is thought to act as a transmembrane linker between the extracellular matrix and intracellular cytoskeleton,5 because α-dystroglycan binds with high affinity to the extracellular matrix component, laminin,5–8 and the intracellular domain of β- …
Can females have Duchenne muscular dystrophy?
Duchenne muscular dystrophy usually affects males. However, females are also affected in rare instances. Approximately 8% of female Duchenne muscular dystrophy (DMD) carriers are manifesting carriers and have muscle weakness to some extent.
Is DMD recessive or dominant?
Duchenne muscular dystrophy is an x-linked recessive genetic disease that is also caused by mutations in the DMD gene. The DMD gene mutations that cause Duchenne muscular dystrophy result in little or no dystrophin protein to be made. Symptoms usually begin in early childhood and progress rapidly.
What kind of mutation causes DMD?
DMD is inherited in an X-linked pattern because the gene that can carry a DMD-causing mutation is on the X chromosome. Every boy inherits an X chromosome from his mother and a Y chromosome from his father, which is what makes him male.