Okadaic acid potentiates heat-induced activation of erk2

AbstractSubjecting exponentially growing HeLa cells to heat shock at 45°C for 30 min leads to retarded migration of erkl and erk2, as revealed on immunoblots indicating their activation. Renaturation gels confirmed activation of erk2 but not erkl. Treatment of cells with okadaic acid (OA) alone marginally upregulated erkl and erk2, whereas simultaneous exposure to heat shock and OA led to a considerably augmented response for erk2 which was approximately 3-fold higher than the sum of heat- and OA-induced activation. Chronic treatment of cells with 12-O-tetradecanoyl-phorbol 13-acetate marginally diminished the extent of erk2 stimulation, but had no influence on the OA-induced potentiation of heat-induced erk2 activity