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.
Huby
R D
RD
Division of Cellular Immunology, National Institute for Medical Research, Mill Hill, London, United Kingdom.
Carlile
G W
GW
Ley
S C
SC
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