Interleukin 2 (IL 2) induces specific mRNA synthesis and secretion of an important immunoregulatory molecule, interferon-gamma (IFN-gamma). We have observed that treatment of an IL 2 independent murine T cell line, BUD-27, with IL 2, calcium ionophore A23187, or agents that activate phospholipid/Ca2+-dependent protein kinase C results in increased IFN-gamma mRNA transcription and release of anti-viral activity. These same agents each induced the subcellular redistribution of protein kinase C from cytosol to plasma membrane in both the BUD-27 cell line and its IL 2-dependent parent, CT6. Ionophore concentrations greater than 1 micron exhibited the most significant induction of IFN-gamma mRNA, which also correlated with the dose of ionophore, inducing translocation of protein kinase C. This correlation between increased mRNA levels and protein kinase C translocation suggests that a calcium-dependent event is involved in induction of IFN-gamma mRNA synthesis. Furthermore, the magnitude of the translocation of protein kinase C from cytosol to plasma membrane corresponded to the physiologic IL 2 dose-response for IFN-gamma secretion. The data suggest that the activation of protein kinase C and/or coordinate elevation of intracellular calcium may provide at least one mechanism of signal transduction for the regulation of IFN-gamma gene transcription.