title: Nonradioactive assay of FLAG-tagged MAPK using ANTI-FLAG antibody-coated multiwell plates.
abstract: We have developed a rapid, sensitive, and quantitative 96-well microplate-based nonradioactive immunoprecipitation/kinase assay to evaluate mitogen-activated protein kinase (MAPK) activity. Three quantitative nonradioactive imunoprecipitation/kinase assays of MAPK were demonstrated on a 96-well microplate coated with ANTI-FLAG M2 antibody (ANTI-FLAG M2 plate): (i) the capture of phosphorylated FLAG-tagged MAPK fusion protein (FLAG-MAPK) from phorbol esters-stimulated, FLAG-MAPK-transfected COS-7 cells, coupled with a very sensitive ELISA procedure to quantitate the level of phosphorylation of FLAG-MAPK; (ii) the in vitro kinase reaction of FLAG-MAPK activity with a substrate and ATP in the same well used to captured the phosphorylated FLAG-MAPK; and (iii) the in vitro kinase reaction of captured non-activated FLAG-MAPK by its upstream kinase from phorbol 12-myristate 13-acetate (PMA)-stimulated COS-7 cells. These results demonstrate that the ANTI-FLAG M2 plate allows for the rapid and quantitative determination of phosphorylation of FLAG-MAPK directly from stimulated, transfected cell lysate. Captured, phosphorylated FLAG-MAPK retains catalytic activity as demonstrated by the phosphorylation of Elk-1 in the same well. Furthermore, phosphorylation of captured FLAG-MAPK by the upstream kinases can be observed directly on the plate. These assays are sensitive, specific, and suitable for handling multiple samples. Thus, the ANTI-FLAG M2 plate forms the basis of a high-throughput screening platform in kinase analysis.
authors.affiliation: Research and Development, Sigma-Aldrich/Biotechnology Division, St. Louis, MO, USA. lzhang@sial.com
authors.forename: L
authors.initials: L
authors.lastname: Zhang
authors.forename: S
authors.initials: S
authors.lastname: Uder
authors.forename: T
authors.initials: T
authors.lastname: Juehne
authors.forename: B
authors.initials: B
authors.lastname: Brizzard
authors.forename: K
authors.initials: K
authors.lastname: Song
mesh_terms: D000818:Animals; D000906:Antibodies / Q000276:immunology; D015153:Blotting, Western; D019556:COS Cells; D018985:Epitopes, B-Lymphocyte / Q000276:immunology; D005240:Feasibility Studies; D006801:Humans; D019169:Jurkat Cells; D020928:Mitogen-Activated Protein Kinases / Q000032:analysis* / Q000235:genetics; D009842:Oligopeptides; D010455:Peptides / Q000032:analysis / Q000235:genetics; D010766:Phosphorylation; D011233:Precipitin Tests / Q000379:methods*; D011993:Recombinant Fusion Proteins / Q000032:analysis; D012680:Sensitivity and Specificity; D014162:Transfection
chemical_list: D000906:Antibodies; D018985:Epitopes, B-Lymphocyte; D009842:Oligopeptides; D010455:Peptides; D011993:Recombinant Fusion Proteins; C085706:FLAG peptide; D020928:Mitogen-Activated Protein Kinases