title: Identification of mitogen-activated protein (MAP) kinase-activated protein kinase-3, a novel substrate of CSBP p38 MAP kinase.
abstract: CSBP p38 is a mitogen-activated protein kinase that is activated in response to stress, endotoxin, interleukin 1, and tumor necrosis factor. Using a catalytically inactive mutant (D168A) of human CSBP2 as the bait in a yeast two-hybrid screen, we have identified and cloned a novel kinase which shares approximately 70% amino acid identity to mitogen-activated protein kinase-activated protein kinase (MAPKAP kinase)-2, and thus was designated MAPKAP kinase-3. The binding of CSBP to MAPKAP kinase-3 was confirmed in vitro by the precipitation of epitope-tagged CSBP1, CSBP2, and CSBP2(D168A) and endogenous CSBP from mammalian cells by a bacterially expressed GST-MAPKAP kinase-3 fusion protein and in vivo by co-precipitation of the epitope-tagged proteins co-expressed in HeLa cells. MAPKAP kinase-3 was phosphorylated by both CSBP1 and CSBP2 and was then able to phosphorylate HSP27 in vitro. Treatment of HeLa cells with sorbitol or TNF resulted in activation of CSBP and MAPKAP kinase-3 and activation of MAPKAP kinase-3 could be blocked by preincubation of cells with SB203580, a specific inhibitor of CSBP kinase activity. These data suggest that MAPKAP kinase-3 is activated by stress and cytokines and is a novel substrate of CSBP both in vitro and in vivo.
authors.affiliation: Department of Gene Expression Sciences, SmithKline Beecham Pharmaceuticals, King of Prussia, Pennsylvania 19406, USA.
authors.forename: M M
authors.initials: MM
authors.lastname: McLaughlin
authors.forename: S
authors.initials: S
authors.lastname: Kumar
authors.forename: P C
authors.initials: PC
authors.lastname: McDonnell
authors.forename: S
authors.initials: S
authors.lastname: Van Horn
authors.forename: J C
authors.initials: JC
authors.lastname: Lee
authors.forename: G P
authors.initials: GP
authors.lastname: Livi
authors.forename: P R
authors.initials: PR
authors.lastname: Young
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D006367:HeLa Cells; D006360:Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D020928:Mitogen-Activated Protein Kinases; D008969:Molecular Sequence Data; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D048051:p38 Mitogen-Activated Protein Kinases; D000099190:MAP-Kinase-Activated Kinase 2
chemical_list: D017871:Calcium-Calmodulin-Dependent Protein Kinases; D006360:Heat-Shock Proteins; D047908:Intracellular Signaling Peptides and Proteins; D020928:Mitogen-Activated Protein Kinases; D017346:Protein Serine-Threonine Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D000099190:MAP-Kinase-Activated Kinase 2; C098416:MAP-kinase-activated kinase 3