MYH11 (Smooth Muscle)

The protein encoded by this gene is a smooth muscle myosin belonging to the myosin heavy chain family. The gene product is a subunit of a hexameric protein that consists of two heavy chain subunits and two pairs of non-identical light chain subunits. It functions as a major contractile protein, converting chemical energy into mechanical energy through the hydrolysis of ATP. The gene encoding a human ortholog of rat NUDE1 is transcribed from the reverse strand of this gene, and its 3' end overlaps with that of the latter. The pericentric inversion of chromosome 16 [inv(16)(p13q22)] produces a chimeric transcript that encodes a protein consisting of the first 165 residues from the N terminus of core-binding factor beta in a fusion with the C-terminal portion of the smooth muscle myosin heavy chain. This chromosomal rearrangement is associated with acute myeloid leukemia of the M4Eo subtype. Alternative splicing generates isoforms that are differentially expressed, with ratios changing during muscle cell maturation. Alternatively spliced transcript variants encoding different isoforms have been identified. [provided by RefSeq, Jul 2008]

Myosin Heavy Chain 11

Muscle contraction.

Cardiac muscle cell development Source: UniProtKB
Elastic fiber assembly Source: UniProtKB
Skeletal muscle myosin thick filament assembly Source: UniProtKB
Smooth muscle contraction Source: UniProtKB

Other locations
Melanosome
Note: Identified by mass spectrometry in melanosome fractions from stage I to stage IV. Thick filaments of the myofibrils.

A chromosomal aberration involving MYH11 is found in acute myeloid leukemia of M4EO subtype. Pericentric inversion inv(16)(p13;q22). The inversion produces a fusion protein consisting of the 165 N-terminal residues of CBF-beta (PEPB2) and the tail region of MYH11.
Aortic aneurysm, familial thoracic 4 (AAT4):
A disease characterized by permanent dilation of the thoracic aorta usually due to degenerative changes in the aortic wall. It is primarily associated with a characteristic histologic appearance known as 'medial necrosis' or 'Erdheim cystic medial necrosis' in which there is degeneration and fragmentation of elastic fibers, loss of smooth muscle cells, and an accumulation of basophilic ground substance.
Megacystis-microcolon-intestinal hypoperistalsis syndrome 2 (MMIHS2):
A form of megacystis-microcolon-intestinal hypoperistalsis syndrome, a congenital visceral myopathy primarily affecting females, and characterized by loss of smooth muscle contraction in the bladder and intestine. Affected individuals present at birth with functional obstruction of intestine, microcolon, dilation of bladder, and secondary hydronephrosis. The majority of cases have a fatal outcome due to malnutrition and sepsis, followed by multiorgan failure. MMIHS2 inheritance is autosomal recessive.
Visceral myopathy 2 (VSCM2):
A form of visceral myopathy, a gastrointestinal pseudo-obstruction disorder characterized by impaired function of enteric smooth muscle cells, intestinal dysmotility and paresis, severe abdominal pain, and malnutrition. The disease shows inter- and intrafamilial variability. VSCM2 inheritance is autosomal dominant.