E3 ligase substrate adaptor SPOP fine-tunes the UPR of pancreatic β cells.

The Cullin-3 E3 ligase adaptor protein SPOP targets proteins for ubiquitination and proteasomal degradation. We previously established the β-cell transcription factor (TF) and human diabetes gene PDX1 as an SPOP substrate, suggesting a functional role for SPOP in the β cell. Here, we generated a β-cell-specific deletion mouse strain ( ) and found that is necessary to prevent aberrant basal insulin secretion and for maintaining glucose-stimulated insulin secretion through impacts on glycolysis and glucose-stimulated calcium flux.

Cell Cycle Regulation of the Pdx1 Transcription Factor in Developing Pancreas and Insulin-Producing β-Cells.

Current evidence indicates that proliferating β-cells express lower levels of some functional cell identity genes, suggesting that proliferating cells are not optimally functional. Pdx1 is important for β-cell specification, function, and proliferation and is mutated in monogenic forms of diabetes. However, its regulation during the cell cycle is unknown.

Metabolic stress activates an ERK/hnRNPK/DDX3X pathway in pancreatic β cells.

Objective: Pancreatic β cell failure plays a central role in the development of type 2 diabetes (T2D). While the transcription factors shaping the β cell gene expression program have received much attention, the post-transcriptional controls that are activated in β cells during stress are largely unknown. We recently identified JUND as a pro-oxidant transcription factor that is post-transcriptionally upregulated in β cells during metabolic stress.