Reactive Oxygen Species, AMP-activated Protein Kinase, and the Transcription Cofactor p300 Regulate α-Tubulin Acetyltransferase-1 (αTAT-1/MEC-17)-dependent Microtubule Hyperacetylation during Cell Stress

Rafah Mackeh,Séverine Lorin,Ameetha Ratier,Najet Mejdoubi-Charef,Anita Baillet,Arnaud Bruneel,Ahmed Hamaï,Patrice Codogno,Christian Poüs,Daniel Perdiz

doi:10.1074/jbc.m113.507400

Abstract

Beyond its presence in stable microtubules, tubulin acetylation can be boosted after UV exposure or after nutrient deprivation, but the mechanisms of microtubule hyperacetylation are still unknown. In this study, we show that this hyperacetylation is a common response to several cellular stresses that involves the stimulation of the major tubulin acetyltransferase MEC-17. We also demonstrate that the acetyltransferase p300 negatively regulates MEC-17 expression and is sequestered on microtubules upon stress. We further show that reactive oxygen species of mitochondrial origin are required for microtubule hyperacetylation by activating the AMP kinase, which in turn mediates MEC-17 phosphorylation upon stress. Finally, we show that preventing microtubule hyperacetylation by knocking down MEC-17 affects cell survival under stress conditions and starvation-induced autophagy, thereby pointing out the importance of this rapid modification as a broad cell response to stress.

Highlights

Tubulin acetylation is a hallmark of microtubule stabilization, which may modulate the binding of microtubule-associated proteins
We show that this hyperacetylation is a common response to several cellular stresses that involves the stimulation of the major tubulin acetyltransferase MEC-17
MT hyperacetylation looks as a general cell response to stress, because we observed it in other cell lines like RPE-1 and mouse embryonic fibroblast

Summary

Background

Tubulin acetylation is a hallmark of microtubule stabilization, which may modulate the binding of microtubule-associated proteins. Appropriate spatial and temporal coordination of cellular signaling is required for optimal cell response In this respect, the microtubule (MT) cytoskeleton has an important role in organizing the cytoplasm by sequestering and releasing transduction factors, allowing their assembly into complexes or supporting their vectorization by molecular motors In starvation-induced autophagy, the stress-induced MAP-kinase JNK is activated via a kinesin-1mediated recruitment on MTs that depends on tubulin acetylation [18] In these studies, tubulin acetylation is not a static process that may only occur on stable MTs, but it is highly inducible, including on the dynamic MT subset, in response to genotoxic stress or to nutrient deprivation [17, 18]. We provide evidence that MT hyperacetylation is required for cell survival in response to oxidative stress and for starvation-induced autophagy stimulation

EXPERIMENTAL PROCEDURES

RESULTS

DISCUSSION