The level of intracellular calcium is tightly regulated in all eukaryotic cells. A modest increase in this level can result in a myriad of physiological responses, most of which are mediated by calmodulin (CaM), a universal calcium sensor. CaM directly modulates the activity of protein kinases and phosphatases, ion channels and nitric oxide synthetases and is generally involved in such diverse processes as cell proliferation, endocytosis, cellular adhesion, protein turnover and smooth muscle contraction. CALML6 (calmodulin-like 6), also known as CAGLP or CALGP, is a 181 amino acid protein that contains four EF-hand domains and shares functional similarity with CaM. Localized to both the nucleus and the cytoplasm, CALML6 is expressed in heart, prostate, ovary, thymus and bone marrow where it may regulate calcium-related events.