CPI17 alpha: Proteins and Enzymes

PKC Potentiated Inhibitor Protein-17 (CPI-17) is a 17 kDa protein (1). Expressed in smooth muscles and neuronal cells, CPI-17 is a myosin phosphatase inhibitor protein. Phosphorylation of CPI-17 at Thr38 enhances its inhibitory effect by 100 fold (2). Once phosphorylated, CPI-17 inhibits PP1c and MLCP holoenzyme activity (3).