Calmodulin

Calmodulin (CaM) is a multifunctional intermediate messenger protein that is expressed in all eukaryotic cells. It is an intracellular target of the secondary messenger Ca^2+ and the binding of Ca^2+ is required for the activation of calmodulin. Once bound to Ca^2+, calmodulin acts as part of a calcium signal transduction pathway by modifying its interactions with various target proteins.

Structure

Calmodulin is a small, highly conserved protein that is 148 amino acids long. The protein has two approximately symmetrical globular domains each of which can bind two calcium ions. The domains are connected by a flexible tether that allows for a large degree of conformational freedom.

Function

Calmodulin mediates processes such as inflammation, metabolism, apoptosis, muscle contraction, intracellular movement, short-term and long-term memory, nerve growth and the immune response. It does this by binding to and regulating a number of different protein targets.

Clinical significance

Mutations in calmodulin genes have been associated with heart arrhythmia, specifically idiopathic ventricular fibrillation and long QT syndrome.

See also

• Calcium signaling
• Calmodulin kinase
• Calmodulin in target cells

References

Calmodulin Resources
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