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FEBS Lett. 2001 Feb 23;491(1-2):85-90.

HIF-1-dependent transcriptional activity is required for oxygen-mediated HIF-1alpha degradation.

Author information

1
Institute of Signaling, Developmental Biology and Cancer Research, CNRS-UMR 6543, Centre Antoine Lacassagne, 33 Avenue Valombrose, 06189 Nice, France. berra@unice.fr

Abstract

Hypoxia-inducible factor-1alpha (HIF-1alpha) plays a central role in oxygen homeostasis. In normoxia, HIF-1alpha is a short lived protein, whereas hypoxia rapidly increases HIF-1alpha protein levels by relaxing its ubiquitin-proteasome-dependent degradation. In this study, we show that the p42/p44 MAP kinase cascade, known to phosphorylate HIF-1alpha, does not modulate the degradation/stabilization profile of HIF-1alpha. However, we present evidence that the rate of HIF-1alpha degradation depends on the duration of hypoxic stress. We demonstrate that degradation of HIF-1alpha is suppressed by: (i) inhibiting general transcription with actinomycin D or (ii) specifically blocking HIF-1-dependent transcriptional activity. In keeping with these findings, we postulate that HIF-1alpha is targetted to the proteasome via a HIF-1alpha proteasome targetting factor (HPTF) which expression is directly under the control of HIF-1-mediated transcriptional activity. Although HPTF is not yet molecularly identified, it is clearly distinct from the von Hippel-Lindau protein (pVHL).

PMID:
11226425
DOI:
10.1016/s0014-5793(01)02159-7
[Indexed for MEDLINE]
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