The role of modulatory calcineurin-interacting proteins in calcineurin signaling

Modulatory calcineurin-interacting proteins (MCIPs), also known as the Down syndrome critical region 1 (DSCR1) and DSCR1-like proteins, are a recently described family of small, structurally related proteins that are preferentially expressed in heart, skeletal muscle, and brain. MCIP proteins can bind to and inhibit calcineurin, a calcium/calmodulin-regulated serine/threonine protein phosphatase that is activated during cardiac hypertrophy and failure. Transcription of the mammalian MCIP1 gene is induced by calcineurin, suggesting that it functions as an endogenous feedback regulator of calcineurin signal transduction. Forced expression of human MCIP1 protein in the hearts of transgenic mice attenuates the hypertrophic response to a broad range of stimuli. This review summarizes work from a number of laboratories on the structure, regulation, and function of MCIP proteins. (C) 2003 Elsevier Science Inc.