Protein-tyrosine kinase Pyk2 is involved in interleukin-2 production by Jurkat T cells via its tyrosine 402.
We established Jurkat transfectants that overexpress Pyk2 or its mutants, K457A (lysine 457 was mutated to alanine), Pyk2-Y402F (tyrosine 402 to phenylalanine), and Pyk2-Y881F to investigate the role of Pyk2 in T cell activation. Pyk2 as well as kinase-inactive Pyk2-K457A, was phosphorylated at tyrosine residues 402, 580, and 881 upon T cell antigen receptor cross-linking, indicating that these residues are phosphorylated by other tyrosine kinase(s). However, no tyrosine phosphorylation of Pyk2-Y402F was detected while more than 60% of the tyrosine phosphorylation was observed in Pyk2-Y881F. Pyk2-Y402F inhibited the activation of endogenous Pyk2. The degree of activation of both c-Jun NH(2)-terminal kinase and p38 mitogen-activated protein kinase but not extracellular signal-regulated protein kinase after concurrent ligation of T cell antigen receptor and CD28 was reduced by more than 50% in the clones expressing Pyk2-Y402F. Consistent with this inhibition, IL-2 production was significantly diminished in the Pyk2-Y402F-expressing clones. Furthermore, we found that Pyk2, when overexpressed, associates with Zap70 and Vav. Taken together, these findings suggest that Pyk2 is involved in the activation of T cells through its tyrosine 402.
Katagiri
T
T
Division of Biochemistry and Cellular Biology, National Institute of Neuroscience, Kodaira, Tokyo 187-8502, Japan. katagiri@ncnp.go.jp
Takahashi
T
T
Sasaki
T
T
Nakamura
S
S
Hattori
S
S
D018106:CD28 Antigens / Q000378:metabolism; D018797:Cell Cycle Proteins; D004789:Enzyme Activation; D051418:Focal Adhesion Kinase 2; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D007376:Interleukin-2 / Q000096:biosynthesis*; D048031:JNK Mitogen-Activated Protein Kinases; D019169:Jurkat Cells; D008213:Lymphocyte Activation; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009154:Mutation; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051567:Proto-Oncogene Proteins c-vav; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013601:T-Lymphocytes / Q000378:metabolism*; D014162:Transfection; D014443:Tyrosine / Q000378:metabolism*; D051746:ZAP-70 Protein-Tyrosine Kinase; D048051:p38 Mitogen-Activated Protein Kinases
D018106:CD28 Antigens; D018797:Cell Cycle Proteins; D007376:Interleukin-2; D011518:Proto-Oncogene Proteins; D051567:Proto-Oncogene Proteins c-vav; D011948:Receptors, Antigen, T-Cell; D011993:Recombinant Fusion Proteins; C496618:VAV1 protein, human; D014443:Tyrosine; D005982:Glutathione Transferase; D011505:Protein-Tyrosine Kinases; D051418:Focal Adhesion Kinase 2; D051746:ZAP-70 Protein-Tyrosine Kinase; C497261:ZAP70 protein, human; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases