Insulin receptor isoform B is required for efficient proinsulin processing in pancreatic ß cells.
iScience
; 27(7): 110017, 2024 Jul 19.
Article
em En
| MEDLINE
| ID: mdl-39021804
ABSTRACT
The insulin receptor (INSR, IR) has two isoforms, IRA and IRB, through alternative splicing. However, their distinct functions in vivo remain unclear. Here we generated ß cell-specific IRB knockout (KO) mice (ßIRBKO). The KO mice displayed worsened hyperinsulinemia and hyperproinsulinemia in diet-induced obesity due to impaired proinsulin processing in ß cells. Mechanistically, loss of IRB suppresses eukaryotic translation initiation factor 4G1 (eIF4G1) by stabilizing the transcriptional receptor sterol-regulatory element binding protein 1 (SREBP1). Moreover, excessive autocrine proinsulin in ßIRBKO mice enhances the activity of extracellular signal-regulated kinase (ERK) through the remaining IRA to further stabilize nuclear SREBP1, forming a feedback loop. Collectively, our study paves the way to dissecting the isoform-specific function of IR in vivo and highlights the important roles of IRB in insulin processing and protecting ß cells from lipotoxicity in obesity.
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MEDLINE
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En
Ano de publicação:
2024
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Article