Inducible expression of a mutant form of MEK1 in Swiss 3T3 cells.
We conditionally overexpressed a MEK1 mutant that contains triple mutations in the regulatory and kinase domains, and investigated its effects on the MAP kinase cascade in Swiss 3T3 cells. Expression of the mutant produced a 60% blockade in MAP kinase activity. However, only a modest blockade in DNA synthesis was observed, without any reductions in the phosphorylation of two proteins known to be substrates of MAP kinase. Moreover, the overexpression of MEK1(3A) failed to block endogenous MEK1 activation, although MEK1(3A) formed complexes with both c-Raf and B-Raf as well as p42/p44 MAPK. These results suggest that there may be multiple biochemical inputs into the MEK/MAPK pathway.
Syu
L J
LJ
Department of Cell Biology, Parke-Davis Pharmaceutical Research Division, Warner-Lambert Co., Ann Arbor, Michigan 48105, USA.
Guan
K L
KL
Saltiel
A R
AR
D016475:3T3 Cells; D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D004247:DNA / Q000096:biosynthesis; D004789:Enzyme Activation; D004790:Enzyme Induction; D004815:Epidermal Growth Factor / Q000494:pharmacology; D048369:MAP Kinase Kinase 1; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases; D020928:Mitogen-Activated Protein Kinases; D009154:Mutation; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D017346:Protein Serine-Threonine Kinases / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D019908:Proto-Oncogene Proteins c-raf / Q000378:metabolism; D019893:Ribosomal Protein S6 Kinases / Q000378:metabolism; D020664:Son of Sevenless Proteins; D013752:Tetracycline / Q000494:pharmacology
D008565:Membrane Proteins; D010982:Platelet-Derived Growth Factor; D020664:Son of Sevenless Proteins; D004815:Epidermal Growth Factor; D004247:DNA; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D019908:Proto-Oncogene Proteins c-raf; D019893:Ribosomal Protein S6 Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; C482127:Map2k1 protein, mouse; D020929:Mitogen-Activated Protein Kinase Kinases; D013752:Tetracycline