PKC-β modulates Ca2+ mobilization through Stim1 phosphorylation

• Published in: Genes & genomics 2022, 44(5), , pp.571-582
• Main Authors: Song, Hye-Jin, Jeon, In-Sook, Kim, Seung Ryul, Park, Kwan Sik, Soh, Jae-Won, Lee, Kwang Youl, Shin, Jae-Cheon, Lee, Hak-Kyo, Choi, Joong-Kook
• Format: Article
• Language: English
• Subjects: Animal Genetics and Genomics; Biomedical and Life Sciences; Calcium (intracellular); Calcium (reticular); Calcium channels; Calcium signalling; Cell differentiation; Cell membranes; Cell migration; Cell proliferation; Diglycerides; Endoplasmic reticulum; Extracellular signal-regulated kinase; Growth factors; GTP-binding protein; Human Genetics; Intracellular; Kinases; Life Sciences; Microbial Genetics and Genomics; Orai1 protein; p21-activated kinase; Phosphorylation; Plant Genetics and Genomics; Protein kinase A; Protein kinase C; Proteins; Research Article; Site-directed mutagenesis; STIM1 protein; 생물학
• ISSN: 1976-9571; 2092-9293
• DOI: 10.1007/s13258-022-01230-3

Background Calcium ions play a pivotal role in cell proliferation, differentiation, and migration. Under basal conditions, the calcium level is tightly regulated; however, cellular activation by growth factors increase the ion level through calcium pumps in the plasma membrane and endoplasmic reticulum for calcium signaling. Orai1 is a major calcium channel in the cell membrane of non-excitable cells, and its activity depends on the stromal interaction molecule 1 (Stim1). Several groups reported that the store-operated calcium entry (SOCE) can be modulated through phosphorylation of Stim1 by protein kinases such as extracellular signal-regulated kinase (ERK), protein kinase A (PKA), and p21-activated kinase (PAK). PKC is a protein kinase that is activated by calcium and diacylglycerol (DAG), but it remains unclear what role activated PKC plays in controlling the intracellular calcium pool. Objectives Here, we investigated whether PKC-β controls intracellular calcium dynamics through Stim1. Methods Several biochemical methods such as immune-precipitation, site directed mutagenesis, in vitro kinase assay were employed to investigate PKC interaction with and phosphorylation of Stim1. Intracellular calcium mobilization, via Stim1 mediated SOCE channel, were studied using in the presence of PKC activator or inhibitor under a confocal microscope. Results Our data demonstrate that PKC interacts with and phosphorylates Stim1 in vitro. phosphorylation of Stim1 at its C-terminal end appears to be important in the regulation of SOCE activity in HEK293 and HeLa cells. Additionally, transient intracellular calcium mobilization assays demonstrate that the SOCE activity was inhibited by PKC activators or activated by PKC inhibitors. Conclusion In sum, our data suggest a repressive role of PKC in regulating calcium entry through SOCE.