Interactome of Ca2+-bound secretagogin in INS-1E cells

By using His6-tagged recombinant human secretagogin in the presence of Ca2+ (100 µM), we precipitated putative interacting partners from INS-1E cells and identified their amino acid sequences by mass spectrometry. We detected canonical interacting proteins participating in vesicle-mediated transport, exocytosis and cytoskeletal organization. Besides, we captured proteins controlling protein folding and (de-)ubiquitination. Our data support that secretagogin modulates protein folding and degradation through protein-protein interactions and interacts with USP9X in β cells to control cell survival.