2001 Volume 41 Issue 2 Pages 115-118
Past studies of individual kinases have demonstrated that protein phosphorylation plays a crucial role in the intracellular signaling pathway of bacterial lipopolysaccharide (LPS). However, no one has determined how many kinases may be activated collectively by LPS stimulation. We examined the spectrum of protein kinases activated in macrophages in response to LPS. Activity was assessed by a renatuiation method that exploited the eability of proteins denatured with sodium dodcyl sulfate and then blotted onto a membrane to regain enzymatic activity after guanidine treatment. Seven electrophoretically-distinct protein kinases with apparent molecular masses of 78, 74, 62, 59, 58, 52, and 48-kDa were detected in lysates from unstimulated murine peritoneal macrophages. An additional three kinases, with apparent molecular masses of 82, 55, and 46-kDa, were detected when the macrophages were stimulated with LPS. The activation of these protein kinases may be dictated by complex signals that are delivered by receptor complexes, including Toll-like receptor 4. These results should provide a clue to clarifying the pleiotropic action of LPS on macrophages.