IRE1-XBP1 pathway regulates oxidative proinsulin folding in pancreatic β cells

Yuichi Tsuchiya, Michiko Saito, Hiroshi Kadokura, Jun ichi Miyazaki, Fumi Tashiro, Yusuke Imagawa, Takao Iwawaki, Kenji Kohno

Research output: Contribution to journalArticlepeer-review

80 Citations (Scopus)


In mammalian pancreatic β cells, the IRE1α-XBP1 pathway is constitutively and highly activated under physiological conditions. To elucidate the precise role of this pathway, we constructed β cell-specific Ire1α conditional knockout (CKO) mice and established insulinoma cell lines in which Ire1α was deleted using the Cre-loxP system. Ire1α CKO mice showed the typical diabetic phenotype including impaired glycemic control and defects in insulin biosynthesis postnatally at 4-20 weeks. Ire1α deletion in pancreatic β cells in mice and insulinoma cells resulted in decreased insulin secretion, decreased insulin and proinsulin contents in cells, and decreased oxidative folding of proinsulin along with decreased expression of five protein disulfide isomerases (PDIs): PDI, PDIR, P5, ERp44, and ERp46. Reconstitution of the IRE1α-XBP1 pathway restored the proinsulin and insulin contents, insulin secretion, and expression of the five PDIs, indicating that IRE1α functions as a key regulator of the induction of catalysts for the oxidative folding of proinsulin in pancreatic β cells.

Original languageEnglish
Pages (from-to)1287-1301
Number of pages15
JournalJournal of Cell Biology
Issue number4
Publication statusPublished - 2018 Apr 1


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