THE PROTEIN-KINASE INHIBITOR, K-252A, DECREASES ELICITOR-INDUCED CA2+ UPTAKE AND K+ RELEASE, AND INCREASES COUMARIN SYNTHESIS IN PARSLEY CELLS

An elicitor preparation from fungal cell walls known to induce coumarin synthesis in suspension-cultured parsley cells also elicits a rapid and transient Ca2+ uptake, K+ release and external alkalinization, and increases uptake of Ca-45(2+) into the cells. The latter three responses were inhibited by the protein kinase inhibitor K-252a at 0.2 mu-M. Elicitor-induced coumarin synthesis, a process which requires gene activation, was greatly enhanced by K-252a. These results suggest that protein phosphorylation might be involved in the initial steps of signal transduction as well as in the long-term induction of coumarin synthesis.