MYH7
Domain
The rodlike tail sequence is highly repetitive, showing cycles of a 28-residue repeat pattern composed of 4 heptapeptides, characteristic for alpha-helical coiled coils (PubMed:26150528, PubMed:26573747). Four skip residues (Skip1: Thr-1188, Skip2: Glu-1385, Skip3: Glu-1582 and Skip4: Gly-1807) introduce discontinuities in the coiled-coil heptad repeats. The first three skip residues are structurally comparable and induce a unique local relaxation of the coiled-coil superhelical pitch and the fourth skip residue lies within a highly flexible molecular hinge that is necessary for myosin incorporation in the bare zone of sarcomeres (PubMed:26150528).
Limited proteolysis of myosin heavy chain produces 1 light meromyosin (LMM) and 1 heavy meromyosin (HMM). HMM can be further cleaved into 2 globular subfragments (S1) and 1 rod-shaped subfragment (S2).
Function
Myosins are actin-based motor molecules with ATPase activity essential for muscle contraction. Forms regular bipolar thick filaments that, together with actin thin filaments, constitute the fundamental contractile unit of skeletal and cardiac muscle.
Involvement in disease
Cardiomyopathy, familial hypertrophic, 1
CMH1
A hereditary heart disorder characterized by ventricular hypertrophy, which is usually asymmetric and often involves the interventricular septum. The symptoms include dyspnea, syncope, collapse, palpitations, and chest pain. They can be readily provoked by exercise. The disorder has inter- and intrafamilial variability ranging from benign to malignant forms with high risk of cardiac failure and sudden cardiac death.
None
The disease is caused by variants affecting the gene represented in this entry.
Congenital myopathy 7A, myosin storage, autosomal dominant
CMYO7A
A skeletal muscle disorder characterized by prominent axial and proximal weakening, spinal stiffness, severe scoliosis, with or without respiratory and cardiac involvement. The age at symptom onset can range from early childhood to late adulthood, and disease severity ranges from asymptomatic to severe muscular weakness and respiratory insufficiency. Histopathological examination shows variable findings including subsarcolemmal hyaline bodies in type 1 fibers.
None
The disease is caused by variants affecting the gene represented in this entry.
Cardiomyopathy, dilated, 1S
CMD1S
A disorder characterized by ventricular dilation and impaired systolic function, resulting in congestive heart failure and arrhythmia. Patients are at risk of premature death.
None
The disease is caused by variants affecting the gene represented in this entry.
Myopathy, distal, 1
MPD1
A muscular disorder characterized by early-onset selective weakness of the great toe and ankle dorsiflexors, followed by weakness of the finger extensors. Mild proximal weakness occasionally develops years later after the onset of the disease.
None
The disease is caused by variants affecting the gene represented in this entry.
Congenital myopathy 7B, myosin storage, autosomal recessive
CMYO7B
A skeletal muscle disorder characterized by the onset of scapuloperoneal muscle weakness in early childhood or young adulthood. Affected individuals have difficulty walking, steppage gait, and scapular winging due to shoulder girdle involvement. The severity and progression of the disorder is highly variable. Most patients develop respiratory insufficiency and restrictive lung disease. Some develop hypertrophic cardiomyopathy. Histopathological examination shows variable findings including subsarcolemmal hyaline bodies in type 1 fibers.
None
The disease is caused by variants affecting the gene represented in this entry.
Left ventricular non-compaction 5
LVNC5
A form of left ventricular non-compaction, a cardiomyopathy due to myocardial morphogenesis arrest and characterized by a hypertrophic left ventricle, a severely thickened 2-layered myocardium, numerous prominent trabeculations, deep intertrabecular recesses, and poor systolic function. Clinical manifestations are variable. Some affected individuals experience no symptoms at all, others develop heart failure. In some cases, left ventricular non-compaction is associated with other congenital heart anomalies. LVNC5 is an autosomal dominant condition.
None
The disease is caused by variants affecting distinct genetic loci, including the gene represented in this entry.
Sequence Similarities
Belongs to the TRAFAC class myosin-kinesin ATPase superfamily. Myosin family.
Tissue Specificity
Both wild type and variant Gln-403 are detected in skeletal muscle (at protein level).
Cellular localization
- Cytoplasm
- Myofibril
- Cytoplasm
- Myofibril
- Sarcomere
- Thick filaments of the myofibrils.
Alternative names
MYHCB, MYH7, Myosin-7, Myosin heavy chain 7, Myosin heavy chain slow isoform, MyHC-slow, MyHC-beta