Identification and characterization of a new mammalian mitogen-activated protein kinase kinase, MKK2.

摘要: Mitogen-activated protein (MAP) kinases are serine/threonine activated by dual phosphorylation on threonine and tyrosine residues. A MAP kinase (MKK1 or MEK1) has been identified as a dual-specificity that is sufficient to phosphorylate p42mapk p44mapk the regulatory Because of multiplicity isoforms diverse circumstances agonists leading their activation, we thought it unlikely single MKK could accommodate this complexity. Indeed, two bands with activity have previously after renaturation following sodium dodecyl sulfate-polyacrylamide gel electrophoresis. We now report molecular cloning characterization second rat cDNA, MKK2. MKK2 cDNA contains an open reading frame encoding 400 amino acids, 7 residues longer than MKK1 (MEK1). The acid sequence 81% identical MKK1, but nucleotide differences occur throughout aligned cDNAs, indicating product distinct gene. mRNAs expressed differently in tissues. Both cDNAs when COS cells displayed ability activate p44mapk, both were vivo response serum, be phosphorylated v-Raf vitro. However, between sites proline-directed predict feedback regulation.