PKCtheta cooperates with atypical PKCzeta and PKCiota in NF-kappaB transactivation of T lymphocytes.
Using yeast two-hybrid, we isolated atypical PKCzeta as a PKCtheta-interacting kinase and demonstrated that it selectively interacted with, and was phosphorylated by, PKCtheta. Importantly, however, both atypical PKCzeta and PKCiota were functionally required in TCR/CD28-mediated activation of NF-kappaB downstream of PKCtheta in Jurkat T cells albeit, activation responses of PKCzeta-deficient CD3+ T cells were comparable with wildtype controls. This normal activation thresholds of PKCzeta-/- T cells suggested that PKCiota, the closest structural relative, might play a compensatory role in TCR/CD28-induced signalling. Consistently, both PKCzeta and PKCiota resided in the plasma membrane lipid raft microdomains of Jurkat as well as primary mouse CD3+ T cells. Thus, PKCtheta, the established constituent of the immunological synapse, physically and functionally interacted with PKCzeta and PKCiota. Together, these data demonstrate that atypical PKCzeta/iota isotypes serve as direct downstream targets of PKCtheta in the signalling pathway leading to NF-kappaB activation in T lymphocytes.
Gruber
Thomas
T
Department for Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, Schoepfstrasse 41, A-6020 Innsbruck, Austria.
Fresser
Friedrich
F
Jenny
Marcel
M
Uberall
Florian
F
Leitges
Michael
M
Baier
Gottfried
G
D000818:Animals; D017252:CD3 Complex; D020134:Catalytic Domain; D049109:Cell Proliferation; D005799:Genes, Dominant; D006801:Humans; D007376:Interleukin-2 / Q000378:metabolism; D007527:Isoenzymes / Q000378:metabolism; D019169:Jurkat Cells; D021962:Membrane Microdomains / Q000201:enzymology; D051379:Mice; D016328:NF-kappa B / Q000378:metabolism*; D011485:Protein Binding; D011493:Protein Kinase C / Q000378:metabolism*; D000074121:Protein Kinase C-theta; D021381:Protein Transport; D051381:Rats; D013379:Substrate Specificity; D013601:T-Lymphocytes / Q000201:enzymology* / Q000378:metabolism; D015533:Transcriptional Activation / Q000235:genetics*; D014162:Transfection; D000099293:Protein Kinase C-lambda; D000099221:Protein Kinase C zeta
D017252:CD3 Complex; D007376:Interleukin-2; D007527:Isoenzymes; D016328:NF-kappa B; D011493:Protein Kinase C; D000074121:Protein Kinase C-theta; D000099293:Protein Kinase C-lambda; D000099221:Protein Kinase C zeta; C076233:PRKCQ protein, human