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J Biol Chem. 2018 Aug 10;293(32):12516-12524. doi: 10.1074/jbc.RA118.002728. Epub 2018 Jun 25.

Peptide-based sequestration of the adaptor protein Nck1 in pancreatic β cells enhances insulin biogenesis and protects against diabetogenic stresses.

Author information

1
From the Research Institute of the McGill University Health Centre, Montreal, Quebec H4A 3J1, Canada.
2
the Division of Experimental Medicine, Department of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada, and.
3
the Institut de Recherches Cliniques de Montreal, Montreal, Quebec H2W 1R7, Canada.
4
the Division of Experimental Medicine, Department of Medicine, McGill University, Montreal, Quebec H4A 3J1, Canada, and jennifer.estall@ircm.qc.ca.
5
From the Research Institute of the McGill University Health Centre, Montreal, Quebec H4A 3J1, Canada, louise.larose@mcgill.ca.

Abstract

One feature of diabetes is the failure of pancreatic β cells to produce insulin, but the molecular mechanisms leading to this failure remain unclear. Increasing evidence supports a role for protein kinase R-like endoplasmic reticulum kinase (PERK) in the development and function of healthy pancreatic β cells. Previously, our group identified the adaptor protein Nck1 as a negative regulator of PERK. Indeed, we demonstrated that Nck1, by directly binding PERK autophosphorylated on Tyr561, limits PERK activation and signaling. Accordingly, we found that stable depletion of Nck1 in β cells promotes PERK activation and signaling, increases insulin biosynthesis, and improves cell viability in response to diabetes-related stresses. Herein, we explored the therapeutic potential of abrogating the interaction between Nck and PERK to improve β-cell function and survival. To do so, we designed and used a peptide containing the minimal PERK sequence involved in binding Nck1 conjugated to the cell-permeable protein transduction domain from the HIV protein TAT. In the current study, we confirm that the synthetic TAT-Tyr(P)561 phosphopeptide specifically binds the SH2 domain of Nck and prevents Nck interaction with PERK, thereby promoting basal PERK activation. Moreover, we report that treatment of β cells with TAT-Tyr(P)561 inhibits glucolipotoxicity-induced apoptosis, whereas it enhances insulin production and secretion. Taken together, our results support the potential of sequestering Nck using a synthetic peptide to enhance basal PERK activation and create more robust β cells.

KEYWORDS:

PERK; adaptor protein; adaptor protein Nck; beta cell (B-cell); cell therapy; cell-penetrating peptide; diabetes; insulin secretion; insulin synthesis; lipotoxicity

PMID:
29941454
PMCID:
PMC6093234
DOI:
10.1074/jbc.RA118.002728
[Indexed for MEDLINE]
Free PMC Article

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