title: Histone deacetylase 1 phosphorylation at S421 and S423 is constitutive in vivo, but dispensable in vitro.
abstract: Histone Deacetylase 1 (HDAC1) is a transcriptional regulator associated with proliferation, apoptosis, and tumorigenesis, although its precise cellular role is unclear. HDAC1 was previously characterized as a phosphoprotein where mutation of phosphorylated S421 and S423 resulted in a loss of deacetylase activity and protein association. Here, the role of phosphorylation in regulating HDAC1 function was examined using phospho-specific antibodies. The antibody studies revealed that phosphorylation at S421 and S423 is constant during the cell cycle, under stress conditions, or in the presence of kinase or phosphatase inhibitors. Further, phosphorylation is dispensable for catalysis or protein association in vitro, as revealed by phosphatase studies. Truncation mutants of HDAC1 demonstrated that binding to Sin3A is promoted by S421 and S423 phosphorylation, while interaction with RbAp48 is not. Taken together, the data are consistent with constitutive phosphorylation of HDAC1 at S421 and S423 in vivo, which is dispensable for activity in vitro.
authors.affiliation: Department of Chemistry, Wayne State University, 5101 Cass Avenue, Detroit, MI 48202, USA.
authors.forename: Paulina
authors.initials: P
authors.lastname: Karwowska-Desaulniers
authors.forename: Anastasia
authors.initials: A
authors.lastname: Ketko
authors.forename: Nayana
authors.initials: N
authors.lastname: Kamath
authors.forename: Mary Kay H
authors.initials: MK
authors.lastname: Pflum
mesh_terms: D045163:Antibodies, Phospho-Specific / Q000494:pharmacology; D000918:Antibody Specificity / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects; D006367:HeLa Cells; D006655:Histone Deacetylases / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D019169:Jurkat Cells; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism*; D011485:Protein Binding / Q000187:drug effects; D012097:Repressor Proteins / Q000378:metabolism; D056264:Sin3 Histone Deacetylase and Corepressor Complex
chemical_list: D045163:Antibodies, Phospho-Specific; D012097:Repressor Proteins; C099683:SIN3A transcription factor; D010768:Phosphoserine; D010749:Phosphoprotein Phosphatases; D006655:Histone Deacetylases; D056264:Sin3 Histone Deacetylase and Corepressor Complex