HDAC-6 interacts with and deacetylates tubulin and microtubules <em>in vivo</em>
Microtubules are cylindrical cytoskeletal structures found in almost all eukaryotic cell types which are involved in a great variety of cellular processes. Reversible acetylation on the ε-amino group of α-tubulin Lys40 marks stabilized microtubule structures and may contribute to regulating microtubule dynamics. Yet, the enzymes catalysing this acetylation/deacetylation have remained unidentified until recently. Here we report that β-tubulin interacts with histone deacetylase-6 (HDAC-6) in a yeast two-hybrid assay and in vitro. We find that HDAC-6 is a micro tubule-associated protein capable of deacetylating α-tubulin in vivo and in vitro. HDAC-6’s microtubule binding and deacetylation functions both depend on the hdac domains. Overexpression of HDAC-6 in mammalian cells leads to tubulin hypoacetylation. In contrast, inhibition of HDAC-6 function by two independent mechanisms—pharmacological (HDAC inhibitors) or genetic (targeted inactivation of HDAC-6 in embryonic stem cells)—leads to hyperacetylation of tubulin and microtubules. Taken together, our data provide evidence that HDAC-6 might act as a dual deacetylase for tubulin and histones, and suggest the possibility that acetylated non-histone proteins might represent novel targets for pharmacological therapy by HDAC inhibitors.
We wish to thank W.Krek and P.Caroni for critical comments on the manuscript, A.Hergovich and Dr Serebriski (Fox Chase Cancer Centre) for technical help and providing reagents, P.Kopp for help with ES cell work, Drs Grozinger (Harvard University), Marshall (University of California, San Francisco) and Seto (H.Lee Moffitt Cancer Centre) for plasmids, and A.Matus and laboratory members for discussions. This work was supported by the Novartis Research Foundation.