The role of protein kinase C in early activation vs. growth of T lymphocytes.

Protein kinase C (PKC) has been implicated in the signaling of a number of cellular responses including activation of T cells. In an approach to study the role of PKC in both early activation and interleukin 2 (IL2)-dependent growth, we have used in vivo phosphorylation of endogenous substrates as a marker for PKC activation. In the present report the requirements for CD3-specific activation of PKC are defined, and it is shown that the conditions required for optimal activation coincide with the induction of a proliferative response. Moreover, it is also shown that IL2 receptor interactions induce only low levels of PKC substrate phosphorylation and that IL2 does not cooperate with CD3-specific signals on the level of PKC activation.