Translocation of the alpha- and beta-isoforms of protein kinase C following activation of human T-lymphocytes.

We have analyzed how activation of human Jurkat T-cells by the mitogenic lectin, concanavalin A (Con A), may affect the cellular distribution of the alpha- and beta-isoforms of protein kinase C (PKC) in T-cells. In non-stimulated cells almost all of the alpha- and beta-PKC was localized to the cytoplasmic compartment. Stimulation with Con A caused a transient translocation of both alpha- and beta-PKC from the cytoplasm to the cell membrane. The alpha-isoform appeared to be translocated to a somewhat greater extent and for a longer period of time than the beta-form. Translocation was maximal between 1 and 5 min for both of the isoforms. 30 min after stimulation, beta-PKC had returned to basal levels, whereas a substantial amount of alpha-PKC remained associated with the particulate fraction. We conclude that activation of human T-cells causes the translocation of at least two different isoforms of PKC, alpha-PKC and beta-PKC.