A role for Wiskott-Aldrich syndrome protein in T-cell receptor-mediated transcriptional activation independent of actin polymerization.
Wiskott-Aldrich syndrome protein (WASP) plays a key role in cytoskeletal rearrangement and transcriptional activation in T-cells. Recent evidence links WASP and related proteins to actin polymerization by the Arp2/3 complex. To study whether the role of WASP in actin polymerization is coupled to T-cell receptor (TCR)-mediated transcriptional activation, we made a series of WASP deletion mutants and tested them for actin co-localization, actin polymerization, and transcriptional activation of NFAT. A WASP mutant with a deletion in the C-terminal region (WASPDeltaC) that is defective in actin polymerization potentiated NFAT transcription following TCR activation by anti-CD3 and anti-CD3/CD28 antibodies, but not by phorbol 12-myristate 13-acetate/ionomycin. Furthermore, cotransfection of a dominant-active mutant (WASP-WH2-C) for Arp2/3 polymerization did not inhibit NFAT activation. Finally, by analyzing a series of WASP double-domain deletion mutants, we determined that the WASP homology-1 domain is responsible for NFAT transcriptional activation. Our results suggest that WASP activates transcription following TCR stimulation in a manner that is independent of its role in Arp2/3-directed actin polymerization.
Onyx Pharmaceuticals, Richmond, California 94806, USA.
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Silvin
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Belisle
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Abo
D000199:Actins / Q000737:chemistry / Q000378:metabolism*; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000378:metabolism; D017930:Genes, Reporter; D006801:Humans; D015759:Ionomycin / Q000494:pharmacology; D019169:Jurkat Cells; D007700:Kinetics; D008156:Luciferases / Q000235:genetics; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016296:Mutagenesis; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D011506:Proteins / Q000235:genetics* / Q000378:metabolism*; D011948:Receptors, Antigen, T-Cell / Q000502:physiology*; D011994:Recombinant Proteins / Q000378:metabolism; D017384:Sequence Deletion; D013601:T-Lymphocytes / Q000502:physiology / Q000648:ultrastructure; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection; D014923:Wiskott-Aldrich Syndrome / Q000235:genetics / Q000378:metabolism; D051316:Wiskott-Aldrich Syndrome Protein
D000199:Actins; D004268:DNA-Binding Proteins; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D011506:Proteins; D011948:Receptors, Antigen, T-Cell; D011994:Recombinant Proteins; D014157:Transcription Factors; C495767:WAS protein, human; D051316:Wiskott-Aldrich Syndrome Protein; D015759:Ionomycin; D008156:Luciferases; D020928:Mitogen-Activated Protein Kinases; D013755:Tetradecanoylphorbol Acetate