Protein kinase C (PKC) plays an integral part in T cell activation and IL-2
secretion. We investigated the role of a particular PKC isoform, PKC beta,
in IL-2 production and secretion. The T cell lymphoma line HuT 78 secretes
IL-2 in response to the phorbol ester PMA. A PKC beta -deficlent clone of
HuT 78, K-4, did not secrete IL-2 in response to PMA stimulation. As assess
ed by RT-PCR, K-4 expressed mRNA for IL-2 following PMA activation, and int
racellular IL-2 protein was detected by immunofluorescence. An enhanced gre
en fluorescent protein-linked PKC beta construct was microinjected into K-4
cells, which,were then stimulated with PMA; those cells that expressed PKC
beta could secrete IL-2, as determined by an in situ immunofluorescent ass
ay. This study demonstrates that PKC beta is not necessary for transcriptio
n of the IL-2 gene or translation of mRNA to protein, but that expression o
f this PKC isoform is critical to the export of IL-2 molecules from T cells
.