The crystal structure of the active form of the C-terminal kinase domain of mitogen- and stress-activated protein kinase 1.

The Hormel Institute University of Minnesota, 801 16th Avenue NE, Austin, MN 55912, USA.
Journal of Molecular Biology (Impact Factor: 3.91). 04/2010; 399(1):41-52. DOI: 10.1016/j.jmb.2010.03.064
Source: PubMed

ABSTRACT Mitogen- and stress-activated protein kinase 1 (MSK1) is a growth-factor-stimulated serine/threonine kinase that is involved in gene transcription regulation and proinflammatory cytokine stimulation. MSK1 is a dual kinase possessing two nonidentical protein kinase domains in one polypeptide. We present the active conformation of the crystal structures of its C-terminal kinase domain in apo form and in complex with a nonhydrolyzable ATP analogue at 2.0 A and 2.5 A resolutions, respectively. Structural analysis revealed substantial differences in the contacts formed by the C-terminal helix, which is responsible for the inactivity of other autoinhibited kinases. In the C-terminal kinase domain of MSK1, the C-terminal alphaL-helix is located in the surface groove, but forms no hydrogen bonds with the substrate-binding loop or nearby helices, and does not interfere with the protein's autophosphorylation activity. Mutational analysis confirmed that the alphaL-helix is inherently nonautoinhibitory. Overexpression of the single C-terminal kinase domain in JB6 cells resulted in tumor-promoter-induced neoplastic transformation in a manner similar to that induced by the full-length MSK1 protein. The overall results suggest that the C-terminal kinase domain of MSK1 is regulated by a novel alphaL-helix-independent mechanism, suggesting that a diverse mechanism of autoinhibition and activation might be adopted by members of a closely related protein kinase family.

  • [Show abstract] [Hide abstract]
    ABSTRACT: The arising critical implications of Rho kinase signaling in cardiovascular diseases have been attracting attention in the pharmacological potential of Rho kinase inhibitors. We identified a novel inhibitor of Rho kinase (2-(1H-indazole-5-yl)amino-4-methoxy -6-piperazino triazine; DW 1865) and characterized its effects in biochemical, cellular, tissue and animal based assays. DW 1865 potently inhibited the kinase activity of both Rho kinase 1 and Rho kinase 2 in vitro, and behaved as an ATP-competitive inhibitor. Interestingly, DW1865 was 10 times more potent in inhibiting Rho kinase activities than fasudil as a selective Rho kinase inhibitor. The activity of DW1865 was shown to be highly selective for Rho kinase in the panel assay of 13 other kinases. In the isolated vascular tissue study, DW1865 exerted vasorelaxation in phenylephrine- or 5-hydroxytriptamine-induced contraction in a concentration-dependent manner manner. In spontaneously hypertensive rats, administration of DW1865 caused a significant and dose-related reduction in blood pressure. Furthermore, DW1865 blocked angiotensin II-induced stress fiber formation and cellular hypertrophy in rat heart-derived H9c2 cells. Taken together, these results suggest that DW1865 is a highly selective and potent Rho kinase inhibitor that will alleviate the pathophysiological actions of Rho kinase such as stress fiber formation, cellular hypertrophy, and hypertension.
    European journal of pharmacology 01/2013; · 2.59 Impact Factor

Full-text (2 Sources)

Available from
Jun 2, 2014