1,25-Dihydroxyvitamin D3 Stimulates Expression and Translocation of Protein Kinase Cα and Cδ via a Nongenomic Mechanism and Rapidly Induces Phosphorylation of a 33-kDa Protein in Acute Promyelocytic NB4 Cells*

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 …