Purification and Properties of Extracellular Signal-Regulated Kinase 1, an Insulin-Stimulated Microtubule-Associated Protein 2 Kinase

Teri G. Boulton, Jill S. Gregory, Melanie H. Cobb

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In rat 1 fibroblasts, insulin has little or no stimulatory effect on the activities of either MAP2 protein kinase or ribosomal protein S6 kinase. In contrast, in rat 1 cells that overexpress the normal human insulin receptor (rat 1 HIRc B; McClain et al. (1987) J. Biol. Chem. 262, 14663–14671), insulin activates both MAP2 and S6 kinase activities close to 5-fold. A MAP2 kinase has been purified from insulin-treated rat 1 HIRc B cells over 6300-fold by chromatography on Q-Sepharose, phenyl-Sepharose, S-Sepharose, phosphocellulose, QAE-Sepharose, UltrogelAcA54, DEAE-cellulose, and a second Q-Sepharose. Its specific activity is approximately 0.8-1 μmol·min −1·mg−1 with MAP2 and 3 μmol·min−1·mg−1 with myelin basic protein. The enzyme preparation contains one major band of Mr = 43 000 upon SDS-polyacrylamide gel electrophoresis, which is immunoblotted by antibodies to phosphotyrosine. A sequence from the 43-kDa band led to the isolation of a cDNA encoding the enzyme, which we have named ERK1 for extracellular signal-regulated kinase (Boulton et al. (1990) Science 249, 64–67).

Original languageEnglish (US)
Pages (from-to)278-286
Number of pages9
Issue number1
StatePublished - Jan 1 1991


ASJC Scopus subject areas

  • Biochemistry

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