Post-cytochrome C protection from apoptosis conferred by a MAPK pathway in Xenopus egg extracts.

Journal Article (Journal Article)

In response to many different apoptotic stimuli, cytochrome c is released from the intermembrane space of the mitochondria into the cytoplasm, where it serves as a cofactor in the activation of procaspase 9. Inhibition of this process can occur either by preventing cytochrome c release or by blocking caspase activation or activity. Experiments involving in vitro reconstitution of apoptosis in cell-free extracts of Xenopus laevis eggs have suggested that extracts arrested in interphase are susceptible to an endogenous apoptotic program leading to caspase activation, whereas extracts arrested in meiotic metaphase are not. We report here that Mos/MEK/MAPK pathways active in M phase-arrested eggs are responsible for rendering them refractory to apoptosis. Interestingly, M phase-arrested extracts are competent to release cytochrome c, yet still do not activate caspases. Concomitantly, we have also demonstrated that recombinant Mos, MEK, and ERK are sufficient to block cytochrome c-dependent caspase activation in purified Xenopus cytosol, which lacks both transcription and translation. These data indicate that the MAP kinase pathway can target and inhibit post-cytochrome c release apoptotic events in the absence of new mRNA/protein synthesis and that this biochemical pathway is responsible for the apoptotic inhibition observed in meiotic X. laevis egg extracts.

Full Text

Duke Authors

Cited Authors

  • Tashker, JS; Olson, M; Kornbluth, S

Published Date

  • February 2002

Published In

Volume / Issue

  • 13 / 2

Start / End Page

  • 393 - 401

PubMed ID

  • 11854398

Pubmed Central ID

  • PMC65635

Electronic International Standard Serial Number (EISSN)

  • 1939-4586

International Standard Serial Number (ISSN)

  • 1059-1524

Digital Object Identifier (DOI)

  • 10.1091/mbc.01-06-0291


  • eng