Calmodulin (CaM) (an abbreviation for CALcium MODULated proteIN) is a calcium-binding protein expressed in all eukaryotic cells. It can bind to and regulate a number of different protein targets, thereby affecting many different cellular functions. Calmodulin 1
is one of nearly twenty human calmodulins.Calmodulin is the archetype of the family of calcium-modulated proteins of which nearly 20 members have been found. They are identified by their occurrence in the cytosol or on membranes facing the cytosol and by a high affinity for calcium. Calmodulin contains 148 amino acids and has 4 calcium-binding motifs. Its functions include roles in growth and the cell cycle as well as in signal transduction and the synthesis and release of neurotransmitters.