Functional processing of nuclear Ca2+/calmodulin-dependent protein kinase phosphatase (CaMKP-N): Evidence for a critical role of proteolytic processing in the regulation of its catalytic activity, subcellular localization and substrate targeting in vivo

► In this study, we found that CaMKP-N bound to ubiquitinated proteins and underwent proteolytic processing. ► The proteolysis was effectively inhibited by the proteasome inhibitors. ► The proteolytic processing changed the subcellular localization and cellular targets of CaMKP-N. ► CaMKP-N was activated when the C-terminal domain was removed by the processing. ► The processing of CaMKP-N regulates its activity, localization and substrate targeting.