Calcium-dependent, calmodulin-stimulated protein phosphatase which plays an essential role in the transduction of intracellular Ca2+-mediated signals . Many of the substrates contain a PxIxIT motif and/or a LxVP motif . In response to increased Ca2+ levels, dephosphorylates and activates phosphatase SSH1 which results in cofilin dephosphorylation. In response to increased Ca2+ levels following mitochondrial depolarization, dephosphorylates DNM1L inducing DNM1L translocation to the mitochondrion . Dephosphorylates heat shock protein HSPB1. Dephosphorylates and activates transcription factor NFATC1 . In response to increased Ca2+ levels, regulates NFAT-mediated transcription probably by dephosphorylating NFAT and promoting its nuclear translocation. Dephosphorylates and inactivates transcription factor ELK1. Dephosphorylates DARPP32 . May dephosphorylate CRTC2 at 'Ser-171' resulting in CRTC2 dissociation from 14-3-3 proteins.