tokens: An in vitro Raf - 1 kinase assay , however , failed to detect LPS - induced Raf - 1 kinase activity in RAW 264 . 7 cells , suggesting that in RAW 264 . 7 cells , Raf - 1 kinase is not an activating component of the LPS signaling pathway regulating MAPK activity or sIL - 1Ra promoter activity .