Regulation of Histone Deacetylase 4 by Binding of 14-3-3 Proteins

Abstract

Histone (de)acetylation is important for the regulation of fundamental biological processes such as gene expression and DNA recombination. Distinct classes of histone deacetylases (HDACs) have been identified, but how they are regulated in vivo remains largely unexplored. Here we describe results demonstrating that HDAC4, a member of class II human HDACs, is localized in the cytoplasm and/or the nucleus. Moreover, we have found that HDAC4 interacts with the 14-3-3 family of proteins that are known to bind specifically to conserved phosphoserine-containing motifs. Deletion analyses suggested that S246, S467, and S632 of HDAC4 mediate this interaction. Consistent with this, alanine substitutions of these serine residues abrogated 14-3-3 binding. Although these substitutions had minimal effects on the deacetylase activity of HDAC4, they stimulated its nuclear localization and thus led to enhanced transcriptional repression. These results indicate that 14-3-3 proteins negatively regulate HDAC4 by preventing its nuclear localization and thereby uncover a novel regulatory mechanism for HDACs.

ACKNOWLEDGMENTS

We thank J. Th'ng for advice on isolation of [³H]acetyl-histones, M. Yoshida for LMB, R. Prywes for anti-MEF2D antibody, M. Park and her laboratory members for kind help with fluorescence microscopy, and V. Giguère for helpful discussions.

This work was supported by funds from the National Cancer Institute of Canada (to X.J.Y.). A.H.W. is the recipient of a Canadian Institutes of Health Research (CIHR) doctoral research award. J.W. received support from the Lady Davis Medical Institute, Montreal, Quebec, Canada. X.J.Y. is a CIHR scholar.

A.H.W., M.J.K., and J.W. made equally significant contributions to this work.

ADDENDUM IN PROOF

A similar conclusion about regulation of HDAC4 by 14-3-3 was also recently reported by C. M. Grozinger and S. L. Schreiber (Proc. Natl. Acad. Sci. USA 97:7835–7840, 2000).