The small GTP-binding protein Rho potentiates AP-1 transcription in T cells.
The Rho family of small GTP-binding proteins is involved in the regulation of cytoskeletal structure, gene transcription, specific cell fate development, and transformation. We demonstrate in this report that overexpression of an activated form of Rho enhances AP-1 activity in Jurkat T cells in the presence of phorbol myristate acetate (PMA), but activated Rho (V14Rho) has little or no effect on NFAT, Oct-1, and NF-kappaB enhancer element activities under similar conditions. Overexpression of a V14Rho construct incapable of membrane localization (CAAX deleted) abolishes PMA-induced AP-1 transcriptional activation. The effect of Rho on AP-1 is independent of the mitogen-activated protein kinase pathway, as a dominant-negative MEK and a MEK inhibitor (PD98059) did not affect Rho-induced AP-1 activity. V14Rho binds strongly to protein kinase Calpha (PKCalpha) in vivo; however, deletion of the CAAX site on V14Rho severely diminished this association. Evidence for a role for PKCalpha as an effector of Rho was obtained by the observation that coexpression of the N-terminal domain of PKCalpha blocked the effects of activated Rho plus PMA on AP-1 transcriptional activity. These data suggest that Rho potentiates AP-1 transcription during T-cell activation.
Chang
J H
JH
Division of Pediatric Oncology, Dana-Farber Cancer Institute, and Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, USA.
Pratt
J C
JC
Sawasdikosol
S
S
Kapeller
R
R
Burakoff
S J
SJ
D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D002462:Cell Membrane / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000096:biosynthesis; D004742:Enhancer Elements, Genetic; D019204:GTP-Binding Proteins / Q000096:biosynthesis / Q000378:metabolism*; D005982:Glutathione Transferase / Q000096:biosynthesis; D051863:Host Cell Factor C1; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis; D007527:Isoenzymes / Q000378:metabolism; D019169:Jurkat Cells / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D016328:NF-kappa B / Q000096:biosynthesis; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D050811:Octamer Transcription Factor-1; D011493:Protein Kinase C / Q000378:metabolism; D051571:Protein Kinase C-alpha; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D017384:Sequence Deletion; D013601:T-Lymphocytes / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D018808:Transcription Factor AP-1 / Q000096:biosynthesis*; D014157:Transcription Factors / Q000096:biosynthesis; D014158:Transcription, Genetic; D014162:Transfection; D020742:rhoA GTP-Binding Protein
D004268:DNA-Binding Proteins; C497692:HCFC1 protein, human; D051863:Host Cell Factor C1; D007376:Interleukin-2; D007527:Isoenzymes; D016328:NF-kappa B; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D050811:Octamer Transcription Factor-1; C494165:POU2F1 protein, human; D011993:Recombinant Fusion Proteins; D018808:Transcription Factor AP-1; D014157:Transcription Factors; D005982:Glutathione Transferase; C496628:PRKCA protein, human; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D019204:GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein; D013755:Tetradecanoylphorbol Acetate