MAP kinase kinase from rabbit skeletal muscle. A novel dual specificity enzyme showing homology to yeast protein kinases involved in pheromone-dependent signal transduction. |
| |
Authors: | S Nakielny D G Campbell P Cohen |
| |
Affiliation: | Department of Biochemistry, University of Dundee, Scotland, UK. |
| |
Abstract: | MAP kinase kinase (MAPKK) was purified 30,000-fold to homogeneity from extracts of rabbit skeletal muscle and shown to be a monomeric protein of apparent molecular mass 44 kDa. MAPKK activated the 42 kDa isoform of MAP kinase by phosphorylation of Thr-183 and Tyr-185, and phosphorylated itself slowly on tyrosine, threonine and serine residues, establishing that it is a 'dual specificity' protein kinase. Peptide sequences from MAPKK were homologous to other protein serine/threonine kinases, especially to the subfamily that includes yeast protein kinases that lie upstream of yeast MAP kinase homologues in the pheromone-dependent mating pathways. |
| |
Keywords: | |
|
|