RNA binding proteins PCBP1 and PCBP2 regulate pancreatic β cell translation

Area of Science:

• Molecular Biology
• Endocrinology
• Cell Biology

Background:

• Tight control of mRNA translation in pancreatic beta cells is crucial for glucose homeostasis and beta cell health.
• RNA binding proteins (RBPs) regulate translational dynamics, but their specific roles and interactions in beta cells are not fully understood.
• PCBP2 was previously identified as a key post-transcriptional regulator of beta cell function.

Purpose of the Study:

• To investigate the relationship between PCBP1 and PCBP2 in regulating beta cell homeostasis and translation.
• To determine the impact of PCBP1 and PCBP2 on glucose metabolism and beta cell viability.

Main Methods:

• Generated mice with beta cell-specific deletion of Pcbp1 and combined Pcbp1/2.
• Utilized single-cell RNA sequencing, qRT-PCR, and western blot to analyze gene expression.
• Employed RNA immunoprecipitation, CRISPR-Cas9, shRNAs, and puromycin labeling to study RNA-protein interactions and global translation rates.

Main Results:

• Pcbp1 deletion alone did not affect glucose homeostasis.
• Combined deletion of Pcbp1 and Pcbp2 led to severe diabetes, reduced beta cell viability, and impaired translation.
• Single-cell RNA sequencing revealed downregulation of translation initiation factors and ribosomal mRNAs in PCBP co-deficient beta cells.
• PCBPs were found to bind and stabilize these target mRNAs, sustaining global translation.

Conclusions:

• PCBP1 and PCBP2 are required for maintaining global mRNA translation rates in beta cells.
• These RNA binding proteins are critical for beta cell function and glucose homeostasis.