1,25-Dihydroxyvitamin D3 selectively translocates PKCalpha to nuclei in ROS 17/2.8 cells.
We have investigated protein kinase C (PKC) regulation by 1,25-(OH)2D3 in the rat osteosarcoma cell line ROS 17/2.8 since previous reports have implicated PKC in the 1,25-(OH)2D3-mediated regulation of osteocalcin gene expression (J. Biol. Chem. 267 (1992) 12562; Endocrinology 136 (1995) 5685). Here we report that 1,25-(OH)2D3 increased PKCalpha, but not PKCbetaI, epsilon or zeta, levels in the nuclear fraction in a time-dependent manner. Unlike PMA, 1,25-(OH)2D3 did not alter the association of any of the expressed PKC isoenzymes with the plasma membrane. Treatment with 20 nM 1,25-(OH)2D3 for 15 min, 30 min, 1 h and 24 h increased PKCalpha levels in the nuclear fraction by 2.3- to 2.6-fold. Nuclear PKCalpha expression was also increased with doses of 1,25-(OH)2D3 as low as a 0.05 nM. 1,25-(OH)2D3-mediated stabilization of osteocalcin mRNA (Arch. Biochem. Biophys. 332 (1996) 142) was inhibited with bisindolylmaleimide treatment, suggesting that PKCalpha may be involved in the 1,25-(OH)2D3-mediated regulation of osteocalcin gene expression.
Rivera-Bermúdez
Moisés A
MA
Northwestern University Medical School, Dept. Molecular Pharmacology and Biological Chemistry, 303 E, Chicago Ave, Chicago, IL 60611, USA. marivera@northwestern.edu
Bertics
Paul J
PJ
Albrecht
Ralph M
RM
Mosavin
Rashid
R
Mellon
William S
WS
D015152:Blotting, Northern; D001859:Bone Neoplasms / Q000188:drug therapy* / Q000201:enzymology; D002117:Calcitriol / Q000494:pharmacology*; D002120:Calcium Channel Agonists / Q000494:pharmacology*; D002467:Cell Nucleus / Q000201:enzymology; D003609:Dactinomycin / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D006801:Humans; D015151:Immunoblotting; D007527:Isoenzymes / Q000378:metabolism*; D015675:Osteocalcin / Q000235:genetics / Q000378:metabolism; D012516:Osteosarcoma / Q000188:drug therapy* / Q000201:enzymology; D011493:Protein Kinase C / Q000378:metabolism*; D051571:Protein Kinase C-alpha; D012333:RNA, Messenger / Q000378:metabolism; D013347:Subcellular Fractions; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013997:Time Factors; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000201:enzymology
D002120:Calcium Channel Agonists; D007527:Isoenzymes; D012333:RNA, Messenger; D015675:Osteocalcin; D003609:Dactinomycin; C496628:PRKCA protein, human; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D002117:Calcitriol; D013755:Tetradecanoylphorbol Acetate