LPS does not stimulate ERK2 activity in a hybrid cell line
LPS was added at a concentration of 1 µg/ml to RAW 264.7 cells or fusion hybrid cells that had been cultured overnight in medium containing 0.5% FCS. At various times after adding LPS the cells were lysed in RIPA buffer and ERK2 activity was assessed using an immune complex kinase assay as described in Materials and Methods. To assay the response to PMA, cells were stimulated with this agent and harvested 15 min afterward. Two representative experiments are shown.