| Popis: |
The unfolded protein response, which is activated during ER stress, counteracts stress conditions by increasing folding capacity and by increasing the degradation of misfolded ER proteins by the ER-Associated Degradation (ERAD) system. Studies using an engineered insulinoma cell line with inducible expression of the Akita folding-deficient insulin have shown a large induction of Herp, a protein that has been implicated in the ERAD pathway. We hypothesized that Herp is an essential protein that regulates the degradation of misfolded insulin during the ER stress response. Indeed, we found that the degradation of mutant insulin is Herp-dependent and that maintaining Herp expression is vital for maintaining cell survival. We have also observed that the expression of Herp mRNA and protein is induced in various cell culture and animal models of diabetes. These results suggest that Herp is an important ER stress response protein that is induced under diabetic conditions in pancreatic β-cells. |
