Microtubule disruption targets HIF-1α mRNA to cytoplasmic P-bodies for translational repression

M Carbonaro, A O'Brate, P Giannakakou - Journal of cell biology, 2011 - rupress.org
M Carbonaro, A O'Brate, P Giannakakou
Journal of cell biology, 2011rupress.org
The hypoxia inducible factor 1α (HIF-1α) is overexpressed in solid tumors, driving tumor
angiogenesis and survival. However, the mechanisms regulating HIF-1α expression in solid
tumors are not fully understood. In this study, we find that microtubule integrity and dynamics
are intricately involved in orchestrating HIF-1α translation. HIF-1α messenger RNA (mRNA)
traffics on dynamic microtubules when it is actively translated. Microtubule perturbation by
taxol (TX) and other microtubule-targeting drugs stalls HIF-1α mRNA transport and releases …
The hypoxia inducible factor 1α (HIF-1α) is overexpressed in solid tumors, driving tumor angiogenesis and survival. However, the mechanisms regulating HIF-1α expression in solid tumors are not fully understood. In this study, we find that microtubule integrity and dynamics are intricately involved in orchestrating HIF-1α translation. HIF-1α messenger RNA (mRNA) traffics on dynamic microtubules when it is actively translated. Microtubule perturbation by taxol (TX) and other microtubule-targeting drugs stalls HIF-1α mRNA transport and releases it from polysomes, suppressing its translation. Immunoprecipitation of the P-body component Argonaute 2 (Ago2) after microtubule disruption shows significant enrichment of HIF-1α mRNAs and HIF-targeting microRNAs (miRNAs). Inhibition of HIF-repressing miRNAs or Ago2 knockdown abrogates TX’s ability to suppress HIF-1α translation. Interestingly, microtubule repolymerization after nocodazole washout allows HIF-1α mRNA to reenter active translation, suggesting that microtubule dynamics exert tight yet reversible control over HIF-1α translation. Collectively, we provide evidence for a new mechanism of microtubule-dependent HIF-1α translation with important implications for cell biology.
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