Thymocyte activation induces the association of the proto-oncoprotein c-cbl and ras GTPase-activating protein with CD5
| Autor: | K M, Dennehy, R, Broszeit, W F, Ferris, A D, Beyers |
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| Rok vydání: | 1998 |
| Předmět: |
Phosphopeptides
T-Lymphocytes Ubiquitin-Protein Ligases Molecular Sequence Data CD5 Antigens Lymphocyte Activation GTP Phosphohydrolases src Homology Domains Mice Proto-Oncogene Proteins Animals Humans Amino Acid Sequence Proto-Oncogene Proteins c-cbl Phosphorylation Mice Knockout GTPase-Activating Proteins Proteins Rats Inbred Strains Protein-Tyrosine Kinases Rats ras GTPase-Activating Proteins Focal Adhesion Kinase 1 Focal Adhesion Protein-Tyrosine Kinases ras Proteins Tyrosine Cell Adhesion Molecules |
| Zdroj: | European journal of immunology. 28(5) |
| ISSN: | 0014-2980 |
| Popis: | Studies of knockout mice indicate that the glycoprotein CD5, which is expressed on Tcells, most thymocytes and a subset of B cells, down-regulates TCR- and B cell receptor (BCR)-mediated signaling. CD5 is associated with the TCR and BCR, and is phosphorylated on cytoplasmic tyrosine residues following antigen receptor ligation. Cross-linking of CD5 or pervanadate stimulation of thymocytes induces the association of a 120-kDa tyrosine-phosphorylated protein with CD5. The proto-oncoprotein c-cbl associates with CD5 in pervanadate-stimulated thymocytes, and reprecipitation analysis demonstrates that the major proportion of CD5-associated pp120 is c-cbl. The GTPase-activating protein for ras (ras GAP), which is not tyrosine phosphorylated following CD5 cross-linking, associates with CD5 in pervanadate-stimulated thymocytes. Using tyrosine-phosphorylated peptides we show that ras GAP interacts in an SH2-mediated manner with the phosphorylated Y429SQP sequence of CD5. Both c-cbl and ras GAP have been proposed to suppress receptor-mediated signaling, and may contribute to CD5-mediated suppression of TCR or BCR signaling. |
| Databáze: | OpenAIRE |
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