The helix–loop–helix structure of the calcium-binding EF hand motif
Calmodulin (CaM) (an abbreviation for calcium-modulated protein) is a multifunctional intermediate calcium-binding messenger protein expressed in all eukaryotic cells.[1] It is an intracellular target of the secondary messengerCa2+, and the binding of Ca2+ is required for the activation of calmodulin. Once bound to Ca2+, calmodulin acts as part of a calcium signal transduction pathway by modifying its interactions with various target proteins such as kinases or phosphatases.[2][3][4]
^Stevens FC (August 1983). "Calmodulin: an introduction". Canadian Journal of Biochemistry and Cell Biology. 61 (8): 906–10. doi:10.1139/o83-115. PMID6313166.