Calmodulin

Is a CALcium MODULated proteIn that can bind to and regulate a multitude of different protein targets, thereby affecting many different cellular functions.

A heat-stable, low-molecular-weight activator protein found mainly in the brain and heart. The binding of calcium ions to this protein allows this protein to bind to cyclic nucleotide phosphodiesterases and to adenyl cyclase with subsequent activation. Thereby this protein modulates cyclic AMP and cyclic GMP levels.

Calcium-dependent regulatory protein. It has four calcium-binding sites, and full occupancy of these sites leads to a marked conformational change, which in turn is related to the ability of the protein to activate or inactivate enzymes. Calmodulin is a calcium transport protein within the cell that carries calcium from the endoplasmic reticulum (where calcium is stored) to sites for its use. It is a delta subunit of phosphorylase kinase.