Map kinase activation in Swiss 3T3 cells stimulated with gastrin-releasing peptide is associated with increased phosphorylation of a 78,000 M(r) protein immunoprecipitated by anti-raf kinase anti-serum.
Addition of 10 nM gastrin-releasing peptide (GRP) to Swiss 3T3 fibroblasts induced a transient (1-2 min) tyrosine phosphorylation and activation of mitogen-activated protein kinase (MAP kinase). Increased activity of 42,000 M(r) MAP kinase was detected with immunochemical methods; however, in situ kinase detection on renaturated SDS-polyacrylamide electrophoresis gel revealed activation of both 42,000 and 44,000 M(r) MAP kinase species. Furthermore, stimulation of 32P-labelled cells with 10 nM GRP for 2 min resulted in an increased phosphorylation of a protein with an approximate molecular mass of 78,000 M(r) in anti-raf kinase and anti-MAP kinase kinase immunoprecipitates of cytosolic extracts from 32P-labelled cells. The presented data demonstrated that GRP induces MAP kinase activation in Swiss 3T3 fibroblasts, and furthermore suggest a role for raf kinase in this process.
Hansson
A
A
Department of Endocrinology, Karolinska Hospital, Stockholm, Sweden.
D016475:3T3 Cells / Q000187:drug effects / Q000201:enzymology; D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation / Q000187:drug effects; D019886:Gastrin-Releasing Peptide; D005755:Gastrins / Q000494:pharmacology*; D007074:Immunoglobulin G / Q000276:immunology; D051379:Mice; D020929:Mitogen-Activated Protein Kinase Kinases; D008970:Molecular Weight; D010455:Peptides / Q000494:pharmacology*; D010766:Phosphorylation; D011233:Precipitin Tests; D011494:Protein Kinases / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000276:immunology / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000276:immunology / Q000378:metabolism*; D019908:Proto-Oncogene Proteins c-raf; D011994:Recombinant Proteins / Q000378:metabolism
D005755:Gastrins; D007074:Immunoglobulin G; D010455:Peptides; D011506:Proteins; D011518:Proto-Oncogene Proteins; D011994:Recombinant Proteins; D019886:Gastrin-Releasing Peptide; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D019908:Proto-Oncogene Proteins c-raf; D020929:Mitogen-Activated Protein Kinase Kinases