Calmodulin mediates the control of a large number of enzymes, ion channels, aquaporins and other proteins by Ca(2+). Among the enzymes to be stimulated by the calmodulin-Ca(2+) complex are a number of protein kinases and phosphatases (By similarity). Together with CCP110 and centrin, is involved in a genetic pathway that regulates the centrosome cycle and progression through cytokinesis (By similarity). Interacts with CEP97, CCP110, TTN/titin and SRY. Interacts with MYO5A and RRAD (By similarity). Interacts with USP6; the interaction is calcium dependent (By similarity). Interacts with CDK5RAP2. Interacts with SCN5A. Interacts with RYR1 and RYR2 (By similarity). Interacts with FCHO1. Interacts with MIP in a 1:2 stoichiometry; the interaction with the cytoplasmic domains from two MIP subunits promotes MIP water channel closure. Interacts with ORAI1; this may play a role in the regulation of ORAI1-mediated calcium transport. Interacts with SYT7 (By similarity). Interacts with MYO10 and MYO1C (By similarity). Interacts with SLC9A1 in a calcium-dependent manner (By similarity). Interacts with HINT1; interaction increases in the presence of calcium ions (By similarity). Interacts with HINT3 (By similarity). Distributed throughout the cell during interphase, but during mitosis becomes dramatically localized to the spindle poles and the spindle microtubules. Ubiquitination results in a strongly decreased activity. Phosphorylation results in a decreased activity. This protein has four functional calcium-binding sites. Belongs to the calmodulin family.