title: Activation of Ras and formation of GAP complex during TPA-induced monocytic differentiation of HL-60 cells.
abstract: In this study, it was shown that the proportion of guanosine triphosphate (GTP)-bound active Ras increased in TPA (12-o-tetradecanoyl phorbol-13-acetate)-induced monocytic differentiation of HL-60 cells. The increase of active Ras was observed at 24 hours after TPA stimulation and attained to threefold (15%) over the proportion in nontreated HL-60 cells. Herbimycin A, an inhibitor of tyrosine kinase, prevented the activation of Ras, as well as the induction of monocytic differentiation. In parallel with the activation of Ras, the proteins with molecular weights of 52, 56, 62, and 190 kD were tyrosine-phosphorylated and formed a complex with GTPase-activating protein (GAP) for Ras. In addition to the 116-kD GAP (type I GAP), the 100-kD GAP (type II GAP) molecule was markedly induced at 24 hours after TPA stimulation of HL-60 cells. These phenomena sustained for a further 24 hours during monocytic differentiation. However, they were not observed during retinoic acid-induced granulocytic differentiation of the cells. The HL-60 transfectants, which expressed a dominant inhibitory Ha-ras Asn17, showed a low level of tyrosine-phosphorylated GAP-associated proteins and did not undergo full differentiation in response to TPA. Taken together, these data indicate that the activation of Ras and GAP complex formation mutually correlate and function downstream of protein-tyrosine kinases in the signaling pathway for monocytic differentiation of HL-60 cells.
authors.affiliation: Tokyo Institute for Immunopharmacology, Inc., Toshima-kur, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Katagiri
authors.forename: S
authors.initials: S
authors.lastname: Hattori
authors.forename: S
authors.initials: S
authors.lastname: Nakamura
authors.forename: T
authors.initials: T
authors.lastname: Yamamoto
authors.forename: T
authors.initials: T
authors.lastname: Yoshida
authors.forename: T
authors.initials: T
authors.lastname: Katagiri
mesh_terms: D016227:Benzoquinones; D002454:Cell Differentiation / Q000187:drug effects*; D003907:Dexamethasone / Q000494:pharmacology; D004789:Enzyme Activation; D020690:GTPase-Activating Proteins; D006098:Granulocytes / Q000166:cytology; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D047029:Lactams, Macrocyclic; D009000:Monocytes / Q000166:cytology*; D009154:Mutation; D015689:Oncogene Protein p21(ras) / Q000378:metabolism*; D010766:Phosphorylation; D019000:Phosphotyrosine; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors; D011506:Proteins / Q000378:metabolism*; D011809:Quinones / Q000494:pharmacology; D017828:Rifabutin / Q000031:analogs & derivatives; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D014162:Transfection; D014212:Tretinoin / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism; D020703:ras GTPase-Activating Proteins
chemical_list: D016227:Benzoquinones; D020690:GTPase-Activating Proteins; D047029:Lactams, Macrocyclic; D011506:Proteins; D011809:Quinones; D020703:ras GTPase-Activating Proteins; D017828:Rifabutin; D019000:Phosphotyrosine; D014443:Tyrosine; D014212:Tretinoin; C020754:herbimycin; D003907:Dexamethasone; D006160:Guanosine Triphosphate; D011505:Protein-Tyrosine Kinases; D015689:Oncogene Protein p21(ras); D013755:Tetradecanoylphorbol Acetate