Cav1.1

Cav1.1 is a protein that in humans is encoded by the CACNA1S gene. It is a voltage-dependent calcium channel found in the T-tubule of skeletal muscle cells. Cav1.1 is also known as the dihydropyridine receptor (DHPR), as it is sensitive to the class of calcium channel blockers known as dihydropyridines.

Function

Cav1.1 is a L-type calcium channel, which means it is activated by a large change in membrane potential. It is responsible for the initiation of excitation-contraction coupling in skeletal muscle. When the muscle cell is depolarized, Cav1.1 undergoes a conformational change that is transmitted to the ryanodine receptor (RyR1) in the sarcoplasmic reticulum (SR). This causes the RyR1 to release calcium ions from the SR, which then bind to troponin C to initiate muscle contraction.

Clinical significance

Mutations in the CACNA1S gene can lead to several muscle disorders, including hypokalemic periodic paralysis and malignant hyperthermia. These conditions are characterized by episodes of muscle weakness or rigidity, respectively, often triggered by certain medications or changes in potassium levels.

See also

• Voltage-dependent calcium channel
• Excitation-contraction coupling
• Sarcoplasmic reticulum

References

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