title: Parathyroid hormone regulates histone deacetylase (HDAC) 4 through protein kinase A-mediated phosphorylation and dephosphorylation in osteoblastic cells.
abstract: Histone deacetylases (HDACs) are crucial regulators of gene expression in transcriptional co-repressor complexes. Previously, we reported that HDAC4 was a basal repressor of matrix metalloproteinase-13 (MMP-13) transcription and parathyroid hormone (PTH) regulates HDAC4 to control MMP-13 promoter activity through dissociation from Runx2. Here, we show that PTH induces the protein kinase A (PKA)-dependent phosphorylation of HDAC4 in the nucleus of the rat osteoblastic cell line, UMR 106-01. We demonstrate that PKA-dependent phosphorylated HDAC4 is released from Runx2 bound to the MMP-13 promoter in these cells. Point mutation of Ser-740 in rHDAC4 prevents the release of HDAC4 from Runx2 on the MMP-13 promoter and also prevents the PTH stimulation of MMP-13 transcription. Thus, PTH-induced phosphorylation of rHDAC4 at Ser-740 is crucial for regulating MMP-13 transcription in osteoblasts. PTH causes degradation of HDAC4, and this product appears in the cytoplasm. The cytoplasmic degradation of HDAC4 is blocked by PKA and lysosomal inhibitors, but is not affected by proteasome, caspase-3, or serine and aspartic protease inhibitors. In addition, the phosphatase inhibitor, okadaic acid, prevents degradation indicating that dephosphorylation is associated with degradation. These mechanisms regulating HDAC4 and their roles in such processes are crucial for bone and chondrocyte development. Our data support a link between PTH regulating HDAC4 phosphorylation by PKA, trafficking, partial degradation, and the control of MMP-13 transcription through association with Runx2.
authors.affiliation: From the Departments of Basic Science and Craniofacial Biology and Endodontics, New York University College of Dentistry, New York, New York 10010.
authors.forename: Emi
authors.initials: E
authors.lastname: Shimizu
authors.affiliation: From the Departments of Basic Science and Craniofacial Biology and.
authors.forename: Teruyo
authors.initials: T
authors.lastname: Nakatani
authors.affiliation: From the Departments of Basic Science and Craniofacial Biology and.
authors.forename: Zhiming
authors.initials: Z
authors.lastname: He
authors.affiliation: From the Departments of Basic Science and Craniofacial Biology and ncp234@nyu.edu.
authors.forename: Nicola C
authors.initials: NC
authors.lastname: Partridge
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002467:Cell Nucleus / Q000201:enzymology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D017931:DNA Primers; D006655:Histone Deacetylases / Q000378:metabolism*; D010006:Osteoblasts / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D010281:Parathyroid Hormone / Q000502:physiology*; D010766:Phosphorylation; D051381:Rats
chemical_list: D017931:DNA Primers; D010281:Parathyroid Hormone; D017868:Cyclic AMP-Dependent Protein Kinases; C559944:HDAC4 protein, rat; D006655:Histone Deacetylases
keywords: Histone Deacetylase (HDAC); Osteoblast; Parathyroid Hormone; Phosphorylation; Protein Kinase A (PKA)