Characterization of an autoinhibitory domain in human mitogen-activated protein kinase-activated protein kinase 2.
Mitogen-activated protein (MAP) kinase-activated protein kinase 2, a Ser/Thr kinase, is phosphorylated and activated by MAP kinase. Sequence analysis of a clone isolated from the human HL-60 cell line revealed a 370-amino acid protein with a proline-rich N terminus, a highly conserved catalytic domain, and a C-terminal region containing a MAP kinase phosphorylation site. To better understand how the kinase is regulated, mutation analysis was used to map the functional domain(s). The wild type recombinant kinase had a low basal activity as detected by phosphorylation of a substrate peptide derived from the N terminus of glycogen synthase. Deletion of the proline-rich N terminus showed little effect on the basal activity. Deletion of the C terminus resulted in a marked increase in catalytic activity either with or without the pretreatment of the kinase by MAP kinase. Further analysis indicated that amino acid residues 339-353 in the C-terminal region were acting as an autoinhibitory domain. A synthetic peptide (RVLKEDKERWEDVK-amide) derived from this autoinhibitory domain inhibited the kinase activity in a concentration-dependent manner. These results suggest a regulatory model for the kinase.
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Department of Pathology, University of Connecticut Health Center, Farmington 06030.
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D000595:Amino Acid Sequence; D002460:Cell Line; D004789:Enzyme Activation; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D010455:Peptides / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism; D016415:Sequence Alignment; D017384:Sequence Deletion; D000099190:MAP-Kinase-Activated Kinase 2
D047908:Intracellular Signaling Peptides and Proteins; D010455:Peptides; D017346:Protein Serine-Threonine Kinases; D000099190:MAP-Kinase-Activated Kinase 2