cDNA cloning of MAP kinase kinase reveals kinase cascade pathways in yeasts to vertebrates.

摘要: Abstract A Xenopus 45 kDa protein has been identified as an immediate upstream factor sufficient for full activation of MAP kinase, and is shown to be capable undergoing autophosphorylation on serine, threonine tyrosine residues. In this study, we show that purified can phosphorylate a kinase-negative mutant kinase residues, suggesting the functions activate kinase. We then report cloning sequencing full-length cDNA encoding it highly homologous four kinases in fission budding yeasts: byr1, wis1, PBS2 STE7. These yeast are therefore suggested function direct activator presumed homolog each signal transduction pathway involved regulation cell cycle progression or cellular responses extracellular signals. Finally, bacterial expression recombinant phosphorylated activated by egg extracts.