Frontiers in Bioscience-Landmark (FBL) is published by IMR Press from Volume 26 Issue 5 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with Frontiers in Bioscience.
PPP3CC feedback regulates IP3-Ca2+ pathway through preventing ITPKC degradation
ITPKC, a susceptibility gene of Kawasaki disease, encodes a kinase that negatively regulates intracellular Ca2+ level and inhibits calcineurin-dependent activation of NFAT by phosphorylating IP3. In this study, we identified a novel ITPKC-interacting protein, namely PPP3CC, using yeast two-hybrid. This interaction was further confirmed by GST pull-down and coimmunoprecipitation assays, and fluorescent microscopy showed co-localization of both proteins in the cell cytoplasm. Our functional studies demonstrated that PPP3CC positively influences the protein level of ITPKC, likely by inhibiting phosphorylation of ITPKC and consequently preventing ITPKC from ubiquitin-mediated protein degradation which requires phosphorylation. Importantly, the protein level of PPP3CC negatively correlates with the cellular level of IP3, suggesting a regulatory role of PPP3CC in the IP3-Ca2+ signaling pathway.