Identification of insulin‐stimulated protein kinase‐1 as the rabbit equivalent of rskmo‐2

• DOI: 10.1111/j.1432-1033.1993.tb17696.x
• Publication Date: 2005-03-04T08:07:31Z
• Authors: Calum SUTHERLAND; David G. CAMPBELL; Philip COHEN
• Keywords: MAP2K7; c-Raf; cGMP-dependent protein kinase; Cyclin-dependent kinase 9; Casein kinase 2

An improved procedure has been developed for the isolation of insulin‐stimulated protein kinase‐1 (ISPK‐1), an S6 kinase‐II homologue, by which 0.5 mg highly purified enzyme can be obtained within four days. The sequences tryptic peptides from ISPK‐1 (100 residues) revealed 100% identity with predicted product rsk mo ‐2, a cDNA clone isolated mouse F2 cell line library [Alcorta, D. A., Crews, C. M., Sweet, L. J., Bankston, L., Jones, S. W. and Erikson, R. (1989) Mol. Cell. Biol. 9 , 3850–3859], demonstrating that ‐2 encodes kinase‐II. Two isoforms mitogen‐activated (MAP) kinase (p42 mapk p44 ) were only ISPK‐1‐reactivating enzymes detected after Mono Q chromatography extracts prepared rabbit skeletal muscle or phaeochromocytoma 12 cells stimulated nerve epidermal growth factors. One residues on phosphorylated p42 was threonine located nine N‐terminal to conserved Ala‐Pro‐Glu motif in C‐terminal domain, analogous location phosphorylation sites essential activity cAMP‐dependent kinase, MAP p34cdc2. A further five same also phosphorylated, probably via autophosphorylation catalysed itself.