The p85α regulatory subunit of phosphoinositide 3-kinase potentiates c-Jun N-terminal kinase-mediated insulin resistance Academic Article uri icon

Overview

MeSH Major

  • Insulin Resistance
  • JNK Mitogen-Activated Protein Kinases
  • Phosphatidylinositol 3-Kinases
  • Protein Subunits

abstract

  • Insulin resistance is a defining feature of type 2 diabetes and the metabolic syndrome. While the molecular mechanisms of insulin resistance are multiple, recent evidence suggests that attenuation of insulin signaling by c-Jun N-terminal kinase (JNK) may be a central part of the pathobiology of insulin resistance. Here we demonstrate that the p85alpha regulatory subunit of phosphoinositide 3-kinase (PI3K), a key mediator of insulin's metabolic actions, is also required for the activation of JNK in states of insulin resistance, including high-fat diet-induced obesity and JNK1 overexpression. The requirement of the p85alpha regulatory subunit for JNK occurs independently of its role as a component of the PI3K heterodimer and occurs only in response to specific stimuli, namely, insulin and tunicamycin, a chemical that induces endoplasmic reticulum stress. We further show that insulin and p85 activate JNK by via cdc42 and MKK4. The activation of this cdc42/JNK pathway requires both an intact N terminus and functional SH2 domains within the C terminus of the p85alpha regulatory subunit. Thus, p85alpha plays a dual role in regulating insulin sensitivity and may mediate cross talk between the PI3K and stress kinase pathways.

publication date

  • April 2007

Research

keywords

  • Academic Article

Identity

Language

  • eng

PubMed Central ID

  • PMC1899914

Digital Object Identifier (DOI)

  • 10.1128/MCB.00079-07

PubMed ID

  • 17283057

Additional Document Info

start page

  • 2830

end page

  • 40

volume

  • 27

number

  • 8