title: Deactylase inhibitors disrupt cellular complexes containing protein phosphatases and deacetylases.
abstract: Affinity isolation of protein serine/threonine phosphatases on the immobilized phosphatase inhibitor microcystin-LR identified histone deacetylase 1(HDAC1), HDAC6, and HDAC10 as novel components of cellular phosphatase complexes. Other HDACs, specifically HDAC2, -3, -4, and -5, were excluded from such complexes. In vitro biochemical studies showed that recombinant HDAC6, but not HDAC4, bound directly to the protein phosphatase (PP)1 catalytic subunit. No association was observed between HDAC6 and PP2A, another major protein phosphatase. PP1 binding was mapped to the second catalytic domain and adjacent C-terminal sequences in HDAC6, and treatment of cells with trichostatin A (TSA) disrupted endogenous HDAC6.PP1 complexes. Consistent with the inhibition of tubulin deactylase activity of HDAC6, TSA enhanced cellular tubulin acetylation, and acetylated tubulin was present in the PP1 complexes from TSA-treated cells. Trapoxin B, a weak HDAC6 inhibitor, and calyculin A, a cell-permeable phosphatase inhibitor, had no effect on the stability of the HDAC6.PP1 complexes or on tubulin acetylation. Mutations that inactivated HDAC6 prevented its incorporation into cellular PP1 complexes and suggested that when bound together both enzymes were active. Interestingly, TSA disrupted all the cellular HDAC.phosphatase complexes analyzed. This study provided new insight into the mechanism by which HDAC inhibitors elicited coordinate changes in cellular protein phosphorylation and acetylation and suggested that changes in these protein modifications at multiple subcellular sites may contribute to the known ability of HDAC inhibitors to suppress cell growth and transformation.
authors.affiliation: Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA.
authors.forename: Matthew H
authors.initials: MH
authors.lastname: Brush
authors.forename: Amaris
authors.initials: A
authors.lastname: Guardiola
authors.forename: John H
authors.initials: JH
authors.lastname: Connor
authors.forename: Tso-Pang
authors.initials: TP
authors.lastname: Yao
authors.forename: Shirish
authors.initials: S
authors.lastname: Shenolikar
mesh_terms: D000107:Acetylation; D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D002477:Cells / Q000187:drug effects* / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D015870:Gene Expression; D056284:Histone Deacetylase 1; D000073864:Histone Deacetylase 6; D056572:Histone Deacetylase Inhibitors; D006655:Histone Deacetylases / Q000032:analysis* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D016297:Mutagenesis, Site-Directed; D010749:Phosphoprotein Phosphatases / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D010766:Phosphorylation; D011817:Rabbits; D014162:Transfection; D014404:Tubulin / Q000032:analysis / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D056572:Histone Deacetylase Inhibitors; D006877:Hydroxamic Acids; D014404:Tubulin; C012589:trichostatin A; D010749:Phosphoprotein Phosphatases; C110550:HDAC1 protein, human; C433811:HDAC6 protein, human; D056284:Histone Deacetylase 1; D000073864:Histone Deacetylase 6; D006655:Histone Deacetylases