1,25-dihydroxyvitamin D-3 stimulates expression and translocation of protein kinase C alpha and C delta via a nongenomic mechanism and rapidly induces phosphorylation of a 33-kDa protein in acute promyelocytic NB4 cells

1,25-Dihydroxyvitamin D-3 (1,25-(OH)(2)D-3) primes NB4 cells for 12-O-tetradecanoylphorbol-13-acetate-induced monocytic differentiation in a dose- and sequence-dependent fashion, Experiments utilizing 1,25-(OH)(2)D-3 analogues and kinase/phosphatase inhibitors suggested that tyrosine kinase and serine/threonine phosphorylation cascades, rather than vitamin D-3 receptor-mediated signals, were involved in 1,25-(OH)(2)D-3 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)(2)D-3 and the nongenomic analogue 1 alpha,25-dihydroxyprevitamin D-3 (HF) increased expression of PKC alpha and PKC delta. PKC alpha and PKC delta were translocated to the nucleus of the cell in response to 1,25-(OH)(2)D-3 or HF. The effects of HF were attenuated by the nongenomic antagonist 1 beta,25-dihydroxyvitamin D-3, 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)(2)D-3 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)(2)D-3 addition. We propose that 1,25-(OH)(2)D-3 primes NB4 cells for 12-O-tetradecanoylphorbol-13-acetate-induced monocytic differentiation by increasing the expression of specific PRC isoforms and inducing the specific phosphorylation of key protein signaling intermediates.