Calmodulin and other EF-hand calcium-binding proteins (CaM) (CaM)

Calmodulin (CaM) and other EF-hand calcium-binding proteins constitute a vital family of intracellular sensors that mediate the effects of calcium ions in eukaryotic cells. These proteins are defined by the presence of the EF-hand motif, a conserved helix-loop-helix structure that undergoes a conformational change upon binding calcium (UniProt: P0DP23). This structural shift exposes hydrophobic surfaces, allowing the proteins to bind and regulate a diverse set of target proteins, including kinases like CaMKII, phosphatases like calcineurin, and various ion channels (PubMed: 21810341). Because they are central to signaling pathways governing muscle contraction, metabolism, and apoptosis, their dysfunction is implicated in diseases such as hypertrophic cardiomyopathy and Alzheimer's disease (PubMed: 28844896). Several pharmacological agents, including certain antipsychotics like trifluoperazine, act as calmodulin antagonists by inhibiting these protein-protein interactions (PubChem: CID 5510). However, the widespread distribution and essential nature of these proteins make them challenging therapeutic targets, often leading to significant off-target effects and safety concerns (PubMed: 15644398). Consequently, current research focuses on developing more selective inhibitors that target specific protein-protein interfaces or specific isoforms within the family.

Other names

EF-hand proteinsCalcium-binding proteinsCaMCalmodulin-like proteinsTroponin C-like proteins

Drugs typically act as calmodulin antagonists by binding to the hydrophobic pockets of the calcium-bound protein, preventing its interaction with and activation of downstream effector enzymes and signaling molecules.