P85α SH2 Domain Phosphorylation by IKK Promotes Feedback Inhibition of PI3K and Akt in Response to Cellular Starvation Academic Article uri icon

Overview

MeSH Major

  • I-kappa B Kinase
  • Phosphatidylinositol 3-Kinases
  • Proto-Oncogene Proteins c-akt
  • Starvation

abstract

  • The IκB kinase (IKK) pathway is an essential mediator of inflammatory, oncogenic, and cell stress pathways. Recently IKK was shown to be essential for autophagy induction in mammalian cells independent of its ability to regulate NF-κB, but the mechanism by which this occurs is unclear. Here we demonstrate that the p85 regulatory subunit of PI3K is an IKK substrate, phosphorylated at S690 in vitro and in vivo in response to cellular starvation. Cells expressing p85 S690A or inhibited for IKK activity exhibit increased Akt activity following cell starvation, demonstrating that p85 phosphorylation is required for starvation-induced PI3K feedback inhibition. S690 is in a conserved region of the p85 cSH2 domain, and IKK-mediated phosphorylation of this site results in decreased affinity for tyrosine-phosphorylated proteins and decreased PI3K membrane localization. Finally, leucine deprivation is shown to be necessary and sufficient for starvation-induced, IKK-mediated p85 phosphorylation and PI3K feedback inhibition.

publication date

  • March 30, 2012

Research

keywords

  • Academic Article

Identity

Language

  • eng

PubMed Central ID

  • PMC3319231

Digital Object Identifier (DOI)

  • 10.1016/j.molcel.2012.01.010

PubMed ID

  • 22342344

Additional Document Info

start page

  • 719

end page

  • 30

volume

  • 45

number

  • 6