Interleukin-2 stimulates association of protein kinase C with plasma membrane

Interleukin-2 (IL-2) is a regulatory peptide important for the growth and differentiation of antigen-specific T lymphocytes and large granular lymphocytes1,2. Interaction of IL-2 with its specific receptor results in the promotion of S-phase progression as well as, in certain circumstances, the production and release of γ-interferon (IFN-γ)3–5. Although the binding of IL-2 with high-affinity specific receptors has been well characterized6,7, the intracellular mechanisms by which this ligand–receptor interaction promotes growth and differentiation are unknown. Here, we present evidence that IL-2/receptor interaction produces a rapid and transient redistribution of protein kinase C (PK-C) from the cytosol to the plasma membrane. Phorbol myristate acetate (PMA) also induces PK-C transposition in an analogous manner, except that PMA-induced PK-C transposition to the plasma membrane is apparently protracted. As phorbol esters have been shown to mimic IL-2 in the regulation of cellular proliferation as well as IFN-γ production8–10, the activation of PK-C by either phorbol esters or IL-2/receptor interaction seems to have a crucial role in signal transduction elicited by these extracellular messengers.