Protein kinase C ? is required for T cell activation and homeostatic proliferation.

ABSTRACT: Protein kinase C ? (PKC?) is abundant in T cells and is recruited to the immunological synapse that is formed between a T cell and an antigen-presenting cell; however, its function in T cells is unknown. We showed that PKC? was required for the activation of mature CD8+ T cells through the T cell receptor. Compared with wild-type T cells, PKC?-/- T cells showed poor proliferation in response to antigen stimulation, a trait shared with T cells deficient in PKC?, which is the most abundant PKC isoform in T cells and was thought to be the only PKC isoform with a specific role in T cell activation. In contrast, only PKC?-deficient T cells showed defective homeostatic proliferation, which requires self-antigen recognition. PKC? was dispensable for thymocyte development; however, thymocytes from mice doubly deficient in PKC? and PKC? exhibited poor development, indicating some redundancy between the PKC isoforms. Deficiency in PKC? or PKC? had opposing effects on the relative numbers of CD4+ and CD8+ T cells. PKC?-/- mice had a higher ratio of CD4+ to CD8+ T cells compared to that of wild-type mice, whereas PKC?-/- mice had a lower ratio. Mice deficient in both isoforms exhibited normal cell ratios. Together, these data suggest that PKC? shares some redundant roles with PKC? in T cell biology and also performs nonredundant functions that are required for T cell homeostasis and activation.

SUBMITTER: Fu G 

PROVIDER: S-EPMC3242502 | biostudies-literature | 2011 Dec

REPOSITORIES: biostudies-literature