Hashimoto Y, Shudo K
Institute of Applied Microbiology, University of Tokyo, Japan.
Biochem Biophys Res Commun. 1990 Feb 14;166(3):1126-32. doi: 10.1016/0006-291x(90)90983-t.
12-O-Tetradecanoylphorbol 13-acetate (TPA) is a potent tumor promoter and is known to induce terminal differentiation of human promyelocytic leukemia cells HL-60 to mature monocytes. To investigate the molecular mechanism of TPA actions, TPA-specific binding proteins in HL-60 were analyzed. Anion exchange high-performance liquid chromatography revealed that HL-60 cells possess TPA-specific binding proteins other than protein kinase C (PKC). One of these TPA-specific binding proteins exists in the cytosolic fraction of HL-60 cells, but translocates into the nuclear fraction of HL-60 cells after the treatment of the cells with TPA. The results suggest that HL-60 cells take up TPA into the nuclei via the TPA-specific binding protein. The TPA-specific binding protein binds TPA, phorbol 12,13-di-butylate, teleocidin B-2, teleocidin B-3, and debromoaplysiatoxin in a mutually competitive manner. However, the protein does not bind to okadaic acid, olivoretin C, retinoic acid, or dioxin. This cytosolic-nuclear tumor promoter-specific binding protein (CN-TPBP) might play an essential role in the action of tumor promoters.
