Uncoupling activation-dependent HS1 phosphorylation from nuclear factor of activated T cells transcriptional activation in Jurkat T cells: differential signaling through CD3 and the costimulatory receptors CD2 and CD28.
CD3, CD2, and CD28 are functionally distinct receptors on T lymphocytes. Engagement of any of these receptors induces the rapid tyrosine phosphorylation of a shared group of intracellular signaling proteins, including Vav, Cbl, p85 phosphoinositide 3-kinase, and the Src family kinases Lck and Fyn. Ligation of CD3 also induces the tyrosine phosphorylation of HS1, a 75-kDa hematopoietic cell-specific intracellular signaling protein of unknown function. We have examined changes in HS1 phosphorylation after differential stimulation of CD3, CD2, and CD28 to elucidate its role in T cells and to further delineate the signaling pathways recruited by these receptors. Unlike ligation of CD3, stimulation with anti-CD28 mAb or CHO cells expressing the CD28 ligands CD80 or CD86 did not lead to tyrosine phosphorylation of HS1 in Jurkat T cells. Additionally, no tyrosine phosphorylation of HS1 was induced by mitogenic pairs of anti-CD2 mAbs capable of activating the transcription factor NFAT (nuclear factor of activated T cells). Costimulation through CD28 and/or CD2 did not modulate the CD3-dependent phosphorylation of HS1. In vivo studies indicated that CD3-induced HSI phosphorylation was dependent upon both the Src family tyrosine kinase Lck and the tyrosine phosphatase CD45, did not require MEK1 kinase activity, and was regulated by protein kinase C activation. Thus, although CD3, CD28, and CD2 activate many of the same signaling molecules, they differed in their capacity to induce the tyrosine phosphorylation of HSI. Furthermore, activation-dependent tyrosine phosphorylation of HS1 was not required for NFAT transcriptional activation.
Hutchcroft
J E
JE
Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, MA 02115, USA.
Slavik
J M
JM
Lin
H
H
Watanabe
T
T
Bierer
B E
BE
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001798:Blood Proteins / Q000378:metabolism*; D018801:CD2 Antigens / Q000502:physiology*; D018106:CD28 Antigens / Q000502:physiology*; D017252:CD3 Complex / Q000502:physiology*; D016466:CHO Cells; D018797:Cell Cycle Proteins; D006224:Cricetinae; D003412:Cricetulus; D004268:DNA-Binding Proteins / Q000502:physiology*; D004789:Enzyme Activation; D006801:Humans; D019169:Jurkat Cells; D017493:Leukocyte Common Antigens / Q000502:physiology; D008213:Lymphocyte Activation; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / Q000502:physiology; D048369:MAP Kinase Kinase 1; D020929:Mitogen-Activated Protein Kinase Kinases; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051567:Proto-Oncogene Proteins c-vav; D015398:Signal Transduction / Q000502:physiology*; D013601:T-Lymphocytes / Q000276:immunology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014157:Transcription Factors / Q000502:physiology*; D014158:Transcription, Genetic
D048868:Adaptor Proteins, Signal Transducing; D000911:Antibodies, Monoclonal; D001798:Blood Proteins; D018801:CD2 Antigens; D018106:CD28 Antigens; D017252:CD3 Complex; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C061909:HCLS1 protein, human; D050778:NFATC Transcription Factors; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D051567:Proto-Oncogene Proteins c-vav; D014157:Transcription Factors; C496618:VAV1 protein, human; D011505:Protein-Tyrosine Kinases; D019860:Lymphocyte Specific Protein Tyrosine Kinase p56(lck); D017346:Protein Serine-Threonine Kinases; D011493:Protein Kinase C; D048369:MAP Kinase Kinase 1; C482125:MAP2K1 protein, human; D020929:Mitogen-Activated Protein Kinase Kinases; D017493:Leukocyte Common Antigens; D013755:Tetradecanoylphorbol Acetate