Signaling pathways mediated by the mitogen-activated protein (MAP) kinase kinase/MAP kinase cascade.
Mitogen-activated protein (MAP) kinase and its direct activator, MAP kinase kinase (MAPKK), comprise the MAPKK/MAP kinase cascade, which may play a pivotal role in a variety of intracellular signal transduction pathways from yeast to human. Vertebrate MAPKK, a dual-specificity kinase, is activated by serine phosphorylation catalyzed by upstream serine/threonine kinases, MAPKK kinases (MAPKK-Ks). MAPKK is, on the other hand, threonine phosphorylated by MAP kinase, although a physiological role of this MAP kinase-mediated phosphorylation of MAPKK is unknown. Biochemical fractionation of extracts from Xenopus mature oocytes revealed two major and one minor peaks for the MAPKK-K activity. One of the major peaks contained a proto-oncogene product c-Mos, while the other peaks did not. These observations, together with a recent finding that several MAPKK-Ks such as Raf-1 and MEKK may function within a cell, suggest a diversity of MAPKK-Ks. A variety of extracellular signals converge at the MAPKK/MAP kinase cascade through different MAPKK-Ks and elicit a wide spectrum of cellular responses. Therefore, mechanisms that control activation of the MAP kinase cascade temporally and spatially may be important for specification of cellular responses.
Matsuda
S
S
Department of Genetics and Molecular Biology, Kyoto University, Japan.
Gotoh
Y
Y
Nishida
E
E
D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D002478:Cells, Cultured; D004789:Enzyme Activation; D006801:Humans; D020929:Mitogen-Activated Protein Kinase Kinases; D010766:Phosphorylation; D011494:Protein Kinases / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases / Q000502:physiology; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000502:physiology; D017231:Proto-Oncogene Proteins c-mos / Q000378:metabolism; D019908:Proto-Oncogene Proteins c-raf; D011994:Recombinant Proteins; D015398:Signal Transduction / Q000502:physiology*; D014981:Xenopus / Q000196:embryology; D015003:Yeasts / Q000201:enzymology
C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D011994:Recombinant Proteins; D011494:Protein Kinases; D017346:Protein Serine-Threonine Kinases; D017231:Proto-Oncogene Proteins c-mos; D019908:Proto-Oncogene Proteins c-raf; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D020929:Mitogen-Activated Protein Kinase Kinases