Signal transduction pathways controllingIns2gene activity and β cell state transitions

Pancreatic β cells exist in low and high insulin gene activity states that are dynamic on a scale of hours to days. Here, we used live 3D imaging, mass spectrometry proteomics, and targeted perturbations of β cell signaling to comprehensively investigate Ins2 (GFP) HIGH and Ins2 (GFP) LOW β cell states. We identified the two Ins2 gene activity states in intact isolated islets, and cells in the same state were more likely to be nearer to each other. We report the proteomes of pure β cells to a depth of 5555 proteins and show that β cells with high Ins2 gene activity had increased mRNA processing factors, as well as increased translation. We identified activators of cAMP signaling (GLP1, IBMX) as powerful drivers of transitions from Ins2 (GFP) LOW to the Ins2 (GFP) HIGH states. Okadaic acid and cyclosporine A had the opposite effects. This study provides new insight into the proteomic profiles and regulation of β cell states.