Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.12.2 (MEK)
 18,161 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Endogenous cardiotonic glycosides bind to the inhibitory binding site of the plasma membrane sodium pump (Na(+)/K(+)-ATPase). Plasma levels of endogenous cardiotonic glycosides increase in several disease states, such as essential hypertension and uremia. Low concentrations of ouabain, which do not inhibit Na(+)/K(+)-ATPase, induce cell proliferation. The mechanisms of ouabain-mediated response remain unclear. Recently, we demonstrated that in opossum kidney (OK) proximal tubular cells, low concentrations of ouabain induce cell proliferation through phosphorylation of protein kinase B (Akt) in a calcium-dependent manner. In the present study, we identified ERK as an upstream kinase regulating Akt activation in ouabain-stimulated cells. Furthermore, we provide evidence that low concentrations of ouabain stimulate Na(+)/K(+)-ATPase-mediated (86)Rb uptake in an Akt-, ERK-, and Src kinase-dependent manner. Ouabain-mediated ERK phosphorylation was inhibited by blockade of intracellular calcium release, calcium entry, tyrosine kinases, and phospholipase C. Pharmacological inhibition of phosphoinositide-3 kinase and Akt failed to inhibit ouabain-stimulated ERK phosphorylation. Ouabain-mediated Akt phosphorylation was inhibited by U0126, a MEK/ERK inhibitor, suggesting that ouabain-mediated Akt phosphorylation is dependent on ERK. In an in vitro kinase assay, active recombinant ERK phosphorylated recombinant Akt on Ser(473). Moreover, transient transfection with constitutively active MEK1, an upstream regulator of ERK, increased Akt phosphorylation and activation, whereas overexpression of constitutively active Akt failed to stimulate ERK phosphorylation. Ouabain at low concentrations also promoted cell proliferation in an ERK-dependent manner. These findings suggest that ouabain-stimulated ERK phosphorylation is required for Akt phosphorylation on Ser(473), cell proliferation, and stimulation of Na(+)/K(+)-ATPase-mediated (86)Rb uptake in OK cells.
 ...
PMID:Ouabain stimulates protein kinase B (Akt) phosphorylation in opossum kidney proximal tubule cells through an ERK-dependent pathway. 1763 16

Lercanidipine, a calcium channel antagonist, is currently employed in the treatment of essential hypertension and angina pectoris. The purpose of this study was to elucidate the anti-proliferative effect of lercanidipine and to investigate the molecular role of this agent. Both in vitro studies and in a balloon injury rat carotid artery model were employed to study the effect of lercanidipine on smooth muscle cell proliferation. Lercanidipine-inhibited rat vascular smooth muscle cell (VSMC) proliferation and migration in a dose-dependent manner following stimulation of VSMC cultures with 10% fetal bovine serum (FBS) and 20 ng/ml platelet-derived growth factor (PDGF)-BB. FBS- and PDGF-BB-stimulated intracellular Ras, MEK1/2, ERK1/2, proliferative cell nuclear antigen (PCNA), and Akt activations were significantly inhibited by lercanidipine; however, lercanidipine did not affect FBS- and PDGF-BB-induced STAT3 phosphorylation. Lercanidipine also inhibited PDGF-receptor beta chain phosphorylation and reactive oxygen species (ROS) production induced by PDGF-BB. Lercanidipine blocked the FBS-inducible progression through the G(0)/G(1) to the S-phase of the cell cycle in synchronized cells. In vivo, 14 days after balloon injury, treatment with 3 and 10 mg/kg lercanidipine resulted in significant inhibition of the neointima/media ratio. Suppression of neointima formation by lercanidipine was dependent on its influence on ERK1/2 phosphorylation. These results demonstrate that lercanidipine can suppress the proliferation of VSMCs via inhibiting cellular ROS, Ras-MEK1/2-ERK1/2, and PI3K-Akt pathways, and suggesting that it may have therapeutic relevance in the prevention of human restenosis.
 ...
PMID:Lercanidipine inhibits vascular smooth muscle cell proliferation and neointimal formation via reducing intracellular reactive oxygen species and inactivating Ras-ERK1/2 signaling. 1897 13