Protein kinase C theta cooperates with Vav1 to induce JNK activity in T-cells.
Here we show that in human T-cell leukemia cells Vav1 and protein kinase C theta (PKCtheta) synergize for the activation of c-Jun N-terminal kinase (JNK) but not p38 MAP kinase. Vav1 and PKCtheta also cooperated to induce transcription of reporter genes controlled either by AP-1 binding sites or the CD28RE/AP composite element contained in the IL-2 promoter by stimulating the binding of transcription factors to these two elements. Dominant negative versions of Vav1 and PKCtheta inhibited CD3/CD28-induced activation of JNK, revealing their relative importance for this activation pathway. Gel filtration experiments revealed the existence of constitutively associated Vav1/PKCtheta heterodimers in extracts from unstimulated T-cells, whereas T-cell costimulation induced the recruitment of Vav1 into high molecular weight complexes. Several experimental approaches showed that Vav1 is located upstream from PKCtheta in the control of the pathway leading to synergistic JNK activation. Vav1-derived signals lead to the activation of JNK by at least two different pathways. The major contribution of Vav1 for the activation of JNK relies on the PKCtheta-mediated Ca(2+)-independent synergistic activation pathway, whereas JNK is also activated by a separate Ca(2+)-dependent signaling route.
German Cancer Research Center, Division of Immunochemistry (G0200), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany.
A
A
Möller
O
O
Dienz
S P
SP
Hehner
W
W
Dröge
M L
ML
Schmitz
D001483:Base Sequence; D018797:Cell Cycle Proteins; D017931:DNA Primers; D004789:Enzyme Activation; D004790:Enzyme Induction; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D007527:Isoenzymes / Q000378:metabolism*; D048031:JNK Mitogen-Activated Protein Kinases; D019169:Jurkat Cells; D020928:Mitogen-Activated Protein Kinases / Q000096:biosynthesis*; D011485:Protein Binding; D011493:Protein Kinase C / Q000378:metabolism*; D000074121:Protein Kinase C-theta; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051567:Proto-Oncogene Proteins c-vav; D013601:T-Lymphocytes / Q000201:enzymology*; D018808:Transcription Factor AP-1 / Q000502:physiology
D018797:Cell Cycle Proteins; D017931:DNA Primers; D007527:Isoenzymes; D011518:Proto-Oncogene Proteins; D051567:Proto-Oncogene Proteins c-vav; D018808:Transcription Factor AP-1; C496618:VAV1 protein, human; C076233:PRKCQ protein, human; D011493:Protein Kinase C; D000074121:Protein Kinase C-theta; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases