hBVR, a dual-specificity kinase (S/T/Y), is as PKC ßII activated by insulin and free radicals (1,2). Presently we report, using 293A cells co –transfected with pcDNA3-hBVR and PKC ßII plasmids, the co-immunoprecipitation of the proteins and co-purification in the GST pull-down assay. hBVR and PKC ßII, but not the reductase and PKC z , transphosphorylated in assay systems supportive of activity of only one of the kinases. PKC ßII K371àR mutant protein (“kinase-dead”) was also a substrate for hBVR. The reductase increased the Vmax but not the apparent Km of PKC ßII for MBP; activation was independent of phospholipids and extended to phosphorylation of S2, a PKC specific substrate. Increase in substrate phosphorylation was blocked by specific inhibitors of conventional PKCs and attenuated by sihBVR. The effect of the latter could be rescued by subsequent over-expression of hBVR. The activation was, to a large extent, a function of hBVR N-terminal chain of valines and intact ATP-binding site and the cysteine-rich C-terminal segment . The Co-PP-activated hBVR phosphorylated a threonine in a peptide corresponding to the T500 in the human PKC ßII activation loop. Neither serine or threonine residues in peptides corresponding to other phosphorylation sites of the PKC ßII, nor PKCz activation loop-derived peptides, were substrates. The phosphorylation of T500 was confirmed by immunoblotting of hBVR:PKC ßII immunocomplex. The potential biological relevance of the hBVR activation of PKC ßII was suggested by the finding that in cells transfected with the PKC ßII, hBVR augmented PMA-mediated c-fos expression, and infection with sihBVR attenuated the response. Also, in cells over expressing hBVR and PKC ßII, as well as in untransfected cells, upon treatment with PMA, the PKC translocated to the plasma membrane and co-localized with hBVR. hBVR activation of PKC ßII underscores its potential function in propagation of signals relayed through PKCs.