Abstract
RhoH is an hematopoietic-specific, GTPase-deficient Rho GTPase that plays a role in T development. We investigated the mechanisms of RhoH function in TCR signaling. We found that the association between Lck and CD3ζ was impaired in RhoH-deficient T cells, due to defective translocation of both Lck and ZAP-70 to the immunological synapse. RhoH with Lck and ZAP-70 localizes in the detergent-soluble membrane fraction where the complex is associated with CD3ζ phosphorylation. To determine if impaired translocation of ZAP-70 was a major determinant of defective T cell development, Rhoh(-/-) bone marrow cells were transduced with a chimeric myristoylation-tagged ZAP-70. Myr-ZAP-70 transduced cells partially reversed the in vivo defects of RhoH-associated thymic development and TCR signaling. Together, our results suggest that RhoH regulates TCR signaling via recruitment of ZAP-70 and Lck to CD3ζ in the immunological synapse. Thus, we define a new function for a RhoH GTPase as an adaptor molecule in TCR signaling pathway.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Animals
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CD3 Complex / metabolism
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Female
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HEK293 Cells
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Humans
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Immunoblotting
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Intracellular Space / metabolism
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Jurkat Cells
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Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / genetics
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Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / metabolism*
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Male
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Mice
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Mice, 129 Strain
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Mice, Inbred C57BL
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Mice, Knockout
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Mice, Transgenic
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Phosphorylation
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Protein Binding
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Receptors, Antigen, T-Cell / genetics
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Receptors, Antigen, T-Cell / metabolism*
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Signal Transduction*
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T-Lymphocytes / metabolism
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Transcription Factors / genetics
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Transcription Factors / metabolism*
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ZAP-70 Protein-Tyrosine Kinase / genetics
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ZAP-70 Protein-Tyrosine Kinase / metabolism*
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rho GTP-Binding Proteins / genetics
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rho GTP-Binding Proteins / metabolism*
Substances
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CD3 Complex
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CD3 antigen, zeta chain
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Receptors, Antigen, T-Cell
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RhoH protein, mouse
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Transcription Factors
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Lymphocyte Specific Protein Tyrosine Kinase p56(lck)
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ZAP-70 Protein-Tyrosine Kinase
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Zap70 protein, mouse
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rho GTP-Binding Proteins