Interactions between the protein-tyrosine kinase ZAP-70, the proto-oncoprotein Vav, and tubulin in Jurkat T cells.
Two molecules involved in signal transduction via the T cell antigen receptor, namely the protein-tyrosine kinase ZAP-70 and the proto-oncoprotein Vav, were found to be constitutively associated with tubulin in Jurkat T cells. Both were able to bind to tubulin independently of one another, as determined by transient transfection into COS-7 cells. The ZAP-70 associated with tubulin was preferentially tyrosine-phosphorylated after T cell antigen receptor stimulation of Jurkat T cells, suggesting that this interaction was functionally significant. Vav was also found to co-immunoprecipitate with ZAP-70 from cell extracts depleted of tubulin. This raised the possibility that Vav might be a substrate for ZAP-70 protein-tyrosine kinase activity. However, tyrosine phosphorylation of Vav preceded that of ZAP-70, indicating that Vav was unlikely to be a downstream target of ZAP-70. The association of ZAP-70 and Vav with tubulin implies that the microtubules may be involved in the signaling function of these two molecules, perhaps by targeting them to their appropriate intracellular location.
Division of Cellular Immunology, National Institute for Medical Research, Mill Hill, London, United Kingdom.
R D
RD
Huby
G W
GW
Carlile
S C
SC
Ley
D000818:Animals; D018797:Cell Cycle Proteins; D002460:Cell Line; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D003600:Cytosol / Q000378:metabolism; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology; D016853:Muromonab-CD3 / Q000494:pharmacology; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000302:isolation & purification / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000302:isolation & purification / Q000378:metabolism*; D051567:Proto-Oncogene Proteins c-vav; D011948:Receptors, Antigen, T-Cell / Q000302:isolation & purification / Q000378:metabolism; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D013601:T-Lymphocytes; D014162:Transfection; D014404:Tubulin / Q000302:isolation & purification / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D051746:ZAP-70 Protein-Tyrosine Kinase
D018797:Cell Cycle Proteins; D007166:Immunosuppressive Agents; D016853:Muromonab-CD3; D011518:Proto-Oncogene Proteins; D051567:Proto-Oncogene Proteins c-vav; D011948:Receptors, Antigen, T-Cell; D011994:Recombinant Proteins; D014404:Tubulin; C496618:VAV1 protein, human; D019000:Phosphotyrosine; D011505:Protein-Tyrosine Kinases; D051746:ZAP-70 Protein-Tyrosine Kinase; C497261:ZAP70 protein, human