Rsk-mediated phosphorylation and 14-3-3ɛ binding of Apaf-1 suppresses cytochrome c-induced apoptosis.

Journal Article (Journal Article)

Many pro-apoptotic signals trigger mitochondrial cytochrome c release, leading to caspase activation and ultimate cellular breakdown. Cell survival pathways, including the mitogen-activated protein kinase (MAPK) cascade, promote cell viability by impeding mitochondrial cytochrome c release and by inhibiting subsequent caspase activation. Here, we describe a mechanism for the inhibition of cytochrome c-induced caspase activation by MAPK signalling, identifying a novel mode of apoptotic regulation exerted through Apaf-1 phosphorylation by the 90-kDa ribosomal S6 kinase (Rsk). Recruitment of 14-3-3ɛ to phosphorylated Ser268 impedes the ability of cytochrome c to nucleate apoptosome formation and activate downstream caspases. High endogenous levels of Rsk in PC3 prostate cancer cells or Rsk activation in other cell types promoted 14-3-3ɛ binding to Apaf-1 and rendered the cells insensitive to cytochrome c, suggesting a potential role for Rsk signalling in apoptotic resistance of prostate cancers and other cancers with elevated Rsk activity. Collectively, these results identify a novel locus of apoptosomal regulation wherein MAPK signalling promotes Rsk-catalysed Apaf-1 phosphorylation and consequent binding of 14-3-3ɛ, resulting in decreased cellular responsiveness to cytochrome c.

Full Text

Duke Authors

Cited Authors

  • Kim, J; Parrish, AB; Kurokawa, M; Matsuura, K; Freel, CD; Andersen, JL; Johnson, CE; Kornbluth, S

Published Date

  • March 2012

Published In

Volume / Issue

  • 31 / 5

Start / End Page

  • 1279 - 1292

PubMed ID

  • 22246185

Pubmed Central ID

  • PMC3297998

Electronic International Standard Serial Number (EISSN)

  • 1460-2075

International Standard Serial Number (ISSN)

  • 0261-4189

Digital Object Identifier (DOI)

  • 10.1038/emboj.2011.491


  • eng