Activation of the MAP kinase homologue RK requires the phosphorylation of Thr‐180 and Tyr‐182 and both residues are phosphorylated in chemically stressed KB cells

Abstract
A MAP kinase homologue, termed the reactivating kinase (RK), lies in a signalling pathway which mediates cellular responses to stress. Here we demonstrate that the stress‐induced activation of the RK in human KB cells is accompanied by the phosphorylation of Thr‐180 and Tyr‐182, and that the phosphorylation of both residues is required for the activation of this enzyme.