MeSH

A diverse superfamily of proteins that function as translocating proteins. They share the common characteristics of being able to bind ACTINS and hydrolyze MgATP. Myosins generally consist of heavy chains which are involved in locomotion, and light chains which are involved in regulation. Within the structure of myosin heavy chain are three domains: the head, the neck and the tail. The head region of the heavy chain contains the actin binding domain and MgATPase domain which provides energy for locomotion. The neck region is involved in binding the light-chains. The tail region provides the anchoring point that maintains the position of the heavy chain. The superfamily of myosins is organized into structural classes based upon the type and arrangement of the subunits they contain.

Year introduced: 2002(1971)

Isoforms of MYOSIN TYPE II, specifically found in the ventricular muscle of the HEART. Defects in the genes encoding ventricular myosins result in FAMILIAL HYPERTROPHIC CARDIOMYOPATHY.

Year introduced: 2002

Myosin type II isoforms found in smooth muscle.

Year introduced: 2002

Myosin type II isoforms found in skeletal muscle.

Year introduced: 2002

Myosin type II isoforms specifically found in the atrial muscle of the heart.

Year introduced: 2002

Myosin type II isoforms found in cardiac muscle.

Year introduced: 2002

A subclass of myosins originally found in the photoreceptor of DROSOPHILA. The heavy chains can occur as two alternatively spliced isoforms of 132 and 174 KDa. The amino terminal of myosin type III is highly unusual in that it contains a protein kinase domain which may be an important component of the visual process.

Year introduced: 2002

An autosomal dominant inherited form of HYPERTROPHIC CARDIOMYOPATHY. It results from any of more than 50 mutations involving genes encoding contractile proteins such as VENTRICULAR MYOSINS; cardiac TROPONIN T; ALPHA-TROPOMYOSIN.

Year introduced: 2002

A subclass of myosins found generally associated with actin-rich membrane structures such as filopodia. Members of the myosin type I family are ubiquitously expressed in eukaryotes. The heavy chains of myosin type I lack coiled-coil forming sequences in their tails and therefore do not dimerize.

Year introduced: 2002

A subclass of myosin found in ACANTHAMOEBA. It is a non-filamentous myosin containing a single 180-kDa myosin heavy chain.

Year introduced: 2002

The subfamily of myosin proteins that are commonly found in muscle fibers. Myosin II is also involved a diverse array of cellular functions including cell division, transport within the GOLGI APPARATUS, and maintaining MICROVILLI structure.

Year introduced: 2002

The larger subunits of MYOSINS. The heavy chains have a molecular weight of about 230 kDa and each heavy chain is usually associated with a dissimilar pair of MYOSIN LIGHT CHAINS. The heavy chains possess actin-binding and ATPase activity.

Year introduced: 1996

The smaller subunits of MYOSINS that bind near the head groups of MYOSIN HEAVY CHAINS. The myosin light chains have a molecular weight of about 20 KDa and there are usually one essential and one regulatory pair of light chains associated with each heavy chain. Many myosin light chains that bind calcium are considered calmodulin-like proteins.

Year introduced: 1996

An enzyme that phosphorylates myosin light chains in the presence of ATP to yield myosin-light chain phosphate and ADP, and requires calcium and CALMODULIN. The 20-kDa light chain is phosphorylated more rapidly than any other acceptor, but light chains from other myosins and myosin itself can act as acceptors. The enzyme plays a central role in the regulation of smooth muscle contraction.

Year introduced: 1987

The protein constituents of muscle, the major ones being ACTINS and MYOSINS. More than a dozen accessory proteins exist including TROPONIN; TROPOMYOSIN; and DYSTROPHIN.

A protein complex of actin and MYOSINS occurring in muscle. It is the essential contractile substance of muscle.

Year introduced: 1973(1971)

Filamentous proteins that are the main constituent of the thin filaments of muscle fibers. The filaments (known also as filamentous or F-actin) can be dissociated into their globular subunits; each subunit is composed of a single polypeptide 375 amino acids long. This is known as globular or G-actin. In conjunction with MYOSINS, actin is responsible for the contraction and relaxation of muscle.

Year introduced: 1982

links capping protein and the Arp2/3 complex to type I myosins through their SH3 domains; from Dictyostelium; Genbank AF388524

Date introduced: July 18, 2001

BERP - Brain Expressed RING finger Protein; interacts with class V myosins; amino acid sequence in first source; GenBank AF036255(rat)

Date introduced: September 29, 1999

a plant myosin with structural similarities to class V myosins; from Arabidopsis thaliana; MW 173 kDa; amino acid sequence given in first source; GenBank Z28389

Date introduced: July 18, 1994