Phosphorylation and activation of nuclear Ca2+/calmodulin-dependent protein kinase phosphatase (CaMKP-N/PPM1E) by Ca2+/calmodulin-dependent protein kinase I (CaMKI)

► CaMKP-N/PPM1E underwent proteolytic processing and translocated to cytosol. ► The proteolysis was effectively inhibited by the proteasome inhibitors. ► Ser-480 of zebrafish CaMKP-N was phosphorylated by cytosolic CaMKI. ► Phosphorylation-mimic mutants of CaMKP-N showed enhanced activity. ► These results suggest that CaMKP-N is regulated by CaMKI.