What does smooth muscle actin do?
What does smooth muscle actin do?
Alpha-smooth muscle actin (SMA), an actin isoform that contributes to cell-generated mechanical tension, is normally restricted to cells of vascular smooth muscle, but SMA can also be expressed in certain non-muscle cells, most notably myofibroblasts.
What cells express smooth muscle actin?
Myofibroblasts are a subset of activated fibrogenic cells with increased expression of ECM proteins and neo-expression of α-smooth muscle actin (α-SMA) [26]. Myofibroblasts are conventionally identified by co-expression of collagen I and α-SMA [27–30].
Where is alpha smooth muscle actin found?
Alpha-smooth muscle actin, a differentiation marker of smooth muscle cells, is present in microfilamentous bundles of pericytes. J Histochem Cytochem.
What is alpha SMA a marker for?
α-Smooth muscle actin (α-SMA) is used as a marker for a subset of activated fibrogenic cells, myofibroblasts, which are regarded as important effector cells of tissue fibrogenesis. α-SMA is not a functional marker of fibrogenic cells in skeletal muscle fibrosis associated with muscular dystrophy.
How does smooth muscle contract?
Smooth muscle contraction is caused by the sliding of myosin and actin filaments (a sliding filament mechanism) over each other. Contraction is initiated by a calcium-regulated phosphorylation of myosin, rather than a calcium-activated troponin system.
What is the function of desmin?
Desmin is a myofibrillar protein that is the chief intermediate filament of skeletal and cardiac muscle [40]. It maintains the structural and functional integrity of the myofibrils and functions as a cytoskeletal protein linking Z bands to the plasma membrane.
What does ACTA2 stand for?
Mutations in smooth muscle alpha-actin (ACTA2) lead to thoracic aortic aneurysms and dissections.
What are the two types of smooth muscle?
Smooth muscle consists of two types: single-unit and multi-unit. Single-unit smooth muscle consists of multiple cells connected through connexins that can become stimulated in a synchronous pattern from only one synaptic input.
Is desmin present in smooth muscle?
Desmin filaments are mainly located at the periphery of Z-disk of striated muscles and at the dense bodies of smooth muscle cells, and they have been postulated to play a critical role in the maintenance of structural and mechanical integrity of the contractile apparatus in muscle tissues.
What is desmin a marker of?
Desmin is a specific marker for rhabdomyosarcomas of human and rat origin.
What is ACTA2 mutation?
ACTA2 gene mutations that are associated with familial TAAD change single protein building blocks (amino acids) in the smooth muscle α-2 actin protein. These changes likely affect the way the protein functions in smooth muscle contraction, interfering with the sarcomeres’ ability to prevent arteries from stretching.