Analysis of a bacterial lipopolysaccharide-activated serine kinase that phosphorylates p65/L-plastin in macrophages.
We previously identified p65/L-plastin as a phosphorylated protein in LPS-stimulated macrophages and determined its phosphorylation site. In vitro kinase assay using peptide substrates revealed that LPS-stimulated kinase activity selectively phosphorylated their serine-5 (Ser-5) residue. Kinase inhibitors for cAMP-dependent kinase such as H-89 inhibited the Ser-5 phosphorylation, but cAMP was not essential for the kinase activity. The LPS-stimulated kinase activity in cytosol fractions of macrophages was recovered as a sharp peak by anion exchange chromatography. These findings suggest that an as yet unknown H-89-sensitive serine kinase is rapidly activated by LPS stimulation and then phosphorylates p65/L-plastin, playing a vital role in macrophage activation.
Hagi
Akifumi
A
Pharmacology Section, Nutrition Research Institute, Otsuka Pharmaceutical Factory, Inc., Naruto, Tokushima, Japan.
Hirata
Hajime
H
Shinomiya
Hiroto
H
D000818:Animals; D003598:Cytoskeletal Proteins; D004789:Enzyme Activation / Q000187:drug effects; D017737:Macrophages, Peritoneal / Q000187:drug effects* / Q000201:enzymology / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008809:Mice, Inbred C3H; D008840:Microfilament Proteins; D010455:Peptides / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011135:Polysaccharides, Bacterial / Q000494:pharmacology*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D013379:Substrate Specificity
D003598:Cytoskeletal Proteins; D008840:Microfilament Proteins; D010455:Peptides; D010750:Phosphoproteins; D011135:Polysaccharides, Bacterial; C066559:Lcp1 protein, mouse; D017346:Protein Serine-Threonine Kinases