title: 1,25-Dihydroxyvitamin D3 stimulates expression and translocation of protein kinase Calpha and Cdelta via a nongenomic mechanism and rapidly induces phosphorylation of a 33-kDa protein in acute promyelocytic NB4 cells.
abstract: 1,25-Dihydroxyvitamin D3 (1,25-(OH)2D3) primes NB4 cells for 12-O-tetradecanoylphorbol-13-acetate-induced monocytic differentiation in a dose- and sequence-dependent fashion. Experiments utilizing 1,25-(OH)2D3 analogues and kinase/phosphatase inhibitors suggested that tyrosine kinase and serine/threonine phosphorylation cascades, rather than vitamin D3 receptor-mediated signals, were involved in 1,25-(OH)2D3 action. Here we show that NB4 cells express the alpha and delta (but not the beta, epsilon, and theta) isoforms of protein kinase C (PKC). Both authentic 1, 25-(OH)2D3 and the nongenomic analogue 1alpha,25-dihydroxyprevitamin D3 (HF) increased expression of PKCalpha and PKCdelta. PKCalpha and PKCdelta were translocated to the nucleus of the cell in response to 1,25-(OH)2D3 or HF. The effects of HF were attenuated by the nongenomic antagonist 1beta,25-dihydroxyvitamin D3, suggesting that changes in PKC expression are mediated by a nongenomic signaling pathway. Consistent with the involvement of serine, threonine, and tyrosine phosphorylation cascades mediating 1,25-(OH)2D3 action, enhanced phosphorylation of a variety of cellular proteins at serine and threonine residues and the specific enhanced phosphotyrosyl content of a 33-kDa protein (vdrp33) were observed immediately after 1,25-(OH)2D3 addition. We propose that 1,25-(OH)2D3 primes NB4 cells for 12-O-tetradecanoylphorbol-13-acetate-induced monocytic differentiation by increasing the expression of specific PKC isoforms and inducing the specific phosphorylation of key protein signaling intermediates.
authors.affiliation: Department of Human Biology and Nutritional Sciences, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
authors.forename: D M
authors.initials: DM
authors.lastname: Berry
authors.forename: R
authors.initials: R
authors.lastname: Antochi
authors.forename: M
authors.initials: M
authors.lastname: Bhatia
authors.forename: K A
authors.initials: KA
authors.lastname: Meckling-Gill
mesh_terms: D015153:Blotting, Western; D002117:Calcitriol / Q000494:pharmacology*; D002460:Cell Line; D004591:Electrophoresis, Polyacrylamide Gel; D015870:Gene Expression / Q000187:drug effects*; D006801:Humans; D007527:Isoenzymes / Q000096:biosynthesis* / Q000302:isolation & purification / Q000378:metabolism; D015473:Leukemia, Promyelocytic, Acute; D008970:Molecular Weight; D010750:Phosphoproteins / Q000302:isolation & purification / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000096:biosynthesis* / Q000302:isolation & purification / Q000378:metabolism; D051571:Protein Kinase C-alpha; D051745:Protein Kinase C-delta; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: D007527:Isoenzymes; D010750:Phosphoproteins; C496628:PRKCA protein, human; C497258:PRKCD protein, human; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D051745:Protein Kinase C-delta; D002117:Calcitriol; D013755:Tetradecanoylphorbol Acetate