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

Cytoplasm, myofibrilCytoplasm, myofibril, sarcomere

Cardiomyopathy, familial hypertrophic, 1

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.

Key component in the assembly and functioning of vertebrate striated muscles. By providing connections at the level of individual microfilaments, it contributes to the fine balance of forces between the two halves of the sarcomere. The size and extensibility of the cross-links are the main determinants of sarcomere extensibility properties of muscle. In non-muscle cells, seems to play a role in chromosome condensation and chromosome segregation during mitosis. Might link the lamina network to ch

CytoplasmNucleus

Myopathy, myofibrillar, 9, with early respiratory failure

An autosomal dominant myopathy characterized by adulthood onset of weakness in proximal, distal, axial and respiratory muscles. Pelvic girdle weakness, foot drop and neck weakness are the main symptoms at onset, but ultimately the weakness usually involves the proximal compartment of both upper and lower limbs. Additional features include variable degrees of Achilles tendon contractures, spinal rigidity and muscle hypertrophy. Respiratory involvement often leads to requirement for non-invasive ventilation support.

Plays an important role in cell protection against oxidative stress and in the regulation of redox-related calcium homeostasis. Regulates the calcium level of the ER by protecting the calcium pump ATP2A2 against the oxidoreductase ERO1A-mediated oxidative damage. Within the ER, ERO1A activity increases the concentration of H(2)O(2), which attacks the luminal thiols in ATP2A2 and thus leads to cysteinyl sulfenic acid formation (-SOH) and SEPN1 reduces the SOH back to free thiol (-SH), thus restor

Endoplasmic reticulum membrane

Congenital myopathy 3 with rigid spine

An autosomal recessive, slowly progressive muscular disorder apparent from birth or early childhood and characterized by hypotonia, proximal muscle weakness, poor axial muscle strength, scoliosis and neck weakness, and a variable degree of spinal rigidity. Most patients remain ambulatory. Early ventilatory insufficiency may lead to death by respiratory failure. Additional features may include facial muscle weakness, amyotrophy, joint contractures, distal hyperlaxity, pulmonary hypertension with secondary cardiac dysfunction, and insulin resistance in patients with a low BMI. Skeletal muscle biopsy typically shows multiminicores and other abnormal non-specific myopathic findings.