Prolonged Pseudohypoxia Targets Ambra1 mRNA to P-Bodies for Translational Repression

PLoS One. 2015 Jun 18;10(6):e0129750. doi: 10.1371/journal.pone.0129750. eCollection 2015.

Abstract

Hypoxia has been associated with several pathological conditions ranging from stroke to cancer. This condition results in the activation of autophagy, a cyto-protective response involving the formation of double-membraned structures, the autophagosomes, in the cytoplasm. In this study, we investigated the cellular mechanisms regulating the autophagy gene Ambra1, after exposure to a hypoxia mimetic, cobalt chloride (CoCl2). We observed that, upon CoCl2 administration, activation of the apoptotic machinery was concomitant with down-regulation of the pro-autophagic factor Ambra1, without affecting transcription. Additionally, co-treating the cells with the caspase inhibitor z-VAD-FMK did not restore Ambra1 protein levels, this implying the involvement of other regulatory mechanisms. Partial re-localization of Ambra1 mRNA to non-translating fractions and cytoplasmic P-bodies was further detected. Thus, in this pseudohypoxic context, Ambra1 mRNA translocation to P-bodies and translational suppression correlated with increased cell death.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics*
  • Apoptosis
  • Autophagy*
  • Cell Hypoxia
  • Cytoplasm / genetics
  • Cytoplasm / metabolism
  • Gene Expression Regulation*
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • Protein Biosynthesis
  • RNA Transport*
  • RNA, Messenger / analysis
  • RNA, Messenger / genetics*
  • RNA, Messenger / metabolism*

Substances

  • AMBRA1 protein, human
  • Adaptor Proteins, Signal Transducing
  • RNA, Messenger