Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A. L. Bayer, A. G. Ferguson, P. A. Lucchesi and A. M. Samarel. PYK2 Expression and Phosphorylation in Neonatal and Adult Cardiomyocytes. Journal of Molecular and Cellular Cardiology (2001) 33, 1017-1030. Proline-rich tyrosine kinase (PYK2) is a Ca(2+)-dependent, non-receptor protein tyrosine kinase involved in growth factor signaling. Although PYK2 is expressed in a variety of tissues, it has not yet been identified in cardiac muscle. Therefore, immunocytochemical and Western blotting techniques were used to examine PYK2 expression and phosphorylation in neonatal and adult rat ventricular cardiomyocytes (NRVM and ARVM, respectively). PYK2 concentration was much greater in neonatal, than in adult ventricular tissue and cardiomyocytes. In cultured cells, PYK2 expression was highly dependent on [Ca(2+)](i)transients and contractile activity. Non-contracting, low-density NRVM in serum-free culture expressed very low levels of PYK2, while high-density, spontaneously contracting NRVM showed a approximately 12-fold increase in PYK2 expression. Conversely, high-density NRVM treated with nifedipine (10 microM, 48 h) to block spontaneous [Ca(2+)](i)transients and contractile activity resulted in a 2.6-fold decrease in PYK2 levels. Similarly, overnight culture of quiescent ARVM markedly reduced PYK2 levels. Chronic treatment (48 h) of cultured NRVM with the hypertrophic agonist endothelin-1 (ET) (10-300 n M) did not significantly increase PYK2 levels, but strongly shifted the ratio of phosphorylated to total PYK2, indicating that PYK2 phosphorylation accompanies cardiomyocyte hypertrophy. Endothelin-1 also acutely activated PYK2 in both cultured NRVM, and in freshly isolated ARVM. These results suggest that PYK2 is involved in the generation of certain aspects of cardiomyocyte hypertrophy.
J Mol Cell Cardiol 2001 May
PMID:Pyk2 expression and phosphorylation in neonatal and adult cardiomyocytes. 1134 23

Hypertrophy is an adaptive response of the heart to myocardial injury or hemodynamic overload that may progress and contribute to cardiac decompensation and eventually to heart failure. The signaling pathways controlling this response in the cardiac myocyte are poorly understood. A data mining effort of a human failed heart cDNA library was undertaken in an effort to identify novel signaling molecules involved in cardiac hypertrophy. This effort identified a novel kinase (MLK7) homologous to the mixed lineage kinase family of proteins. The mixed lineage kinases are mitogen-activated protein kinase kinase kinases (MAPKKKs) which activate stress activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) and p38 kinase pathways. They contain a catalytic domain with homology to both serine/threonine and tyrosine-specific kinases and a dual leucine zipper. MLK7 is identical to leucine zipper and sterile-alpha motif protein kinase (ZAK) through the leucine zipper domain but has a completely divergent COOH-terminus and shares approximately 40% homology with the other MLKs overall. Expression of MLK7 mRNA is most abundant in skeletal muscle and heart, with expression restricted to the cardiac myocyte. The recombinant histidine tagged MLK7 expressed and purified from insect cells exhibited serine/threonine kinase activity in vitro with myelin basic protein as substrate. When expressed in cardiac myocytes, MLK7 activated SAPK/JNK1, and ERK and p38 to a lesser extent. Additionally, MLK7 altered fetal gene expression and increased protein synthesis in cardiac myocytes. These data suggest that MLK7 is a new member of the mixed lineage kinase family that modulates cardiac SAPK/JNK pathway and may play a role in cardiac hypertrophy and progression to heart failure.
J Mol Cell Cardiol 2001 Sep
PMID:Tissue distribution and functional expression of a cDNA encoding a novel mixed lineage kinase. 1154 52

Beta-adrenergic stimulation of ventricular myocytes has been shown to induce apoptosis; however, the cellular mechanisms involved in this pathway have not been completely characterized. This study examines the role of protein kinase C (PKC) in the signaling cascade that mediates beta-adrenergic stimulation-induced apoptosis. Stimulation of beta-adrenergic receptors using isoproterenol (ISO, 1-10 microm, 24 h) induced apoptosis in cultured adult rat ventricular myocytes (ARVM) in a dose-dependent manner. Treatment with ISO significantly resulted in the membrane translocation of PKC(epsilon), but not of PKC alpha or delta in ARVM. The activation of PKC(epsilon) by ISO was confirmed using an immune complex kinase assay. To address whether PKC(epsilon) is involved in the mechanism of ISO-induced apoptosis, we used the PKC(epsilon)-specific translocation inhibitor peptide, epsilonV1-2. Peptide epsilonV1-2 significantly blocked the translocation of PKC(epsilon), as well as the enzymatic action of PKC(epsilon), resulting from ISO stimulation. The inhibition of PKC(epsilon) attenuated ISO-induced apoptosis as measured by terminal deoxynucleotidyltransferase nick-end labeling (TUNEL) assay (18.2+/-3.8%v 49.0+/-2.4%P<0.05), while a PKC delta-specific peptide translocation inhibitor (delta V1-1) failed to do so (39.8+/-7.8%). In the presence of ISO, PKC(epsilon) inhibition by epsilonV1-2 was found to significantly enhance activity of ERK, but not that of Akt/PKB. Inhibition of ERK activation by PD 98059 (10-50 microm) attenuated the epsilonV1-2 peptide-mediated anti-apoptotic effect, thus suggesting that ERK activation is involved in this anti-apoptotic effect. Therefore, our results suggest that activation of PKC(epsilon) downstream of beta-adrenergic stimulation promotes apoptosis largely via inhibition of an ERK activation-dependent anti-apoptotic effect.
J Mol Cell Cardiol 2001 Oct
PMID:Protein kinase C(epsilon) modulates apoptosis induced by beta -adrenergic stimulation in adult rat ventricular myocytes via extracellular signal-regulated kinase (ERK) activity. 1160 22

Endothelin-1 (Et-1) is a peptide synthesized by endothelial cells (ECs) both in culture and in vivo. Cyclic strain induces gene expression of Et-1, however, the molecular mechanisms remain unclear. Since cyclic strain induces a sustained increase in intracellular reactive oxygen species (ROS), we hypothesized that the ROS could be a modulator in strain-induced Et-1 gene expression. Human umbilical vein ECs (HUVECs) subjected to cyclic strain had increased Et-1 secretion. Pretreatment of HUVECs with antioxidants, catalase (300 U/ml) or 1,3-dimethyl-2-thiourea (DMTU, 0.1 mm), abolished the strain-induced Et-1 release. ECs strained for 6 h had elevated Et-1 mRNA levels. In contrast, ECs treated with catalase or DMTU did not have increase Et-1 mRNA levels stimulated by cyclic strain. Bovine aortic ECs (BAECs) transfected with fusion plasmid containing Et-1 5'-flanking sequence (4.4 kb) and chloramphenicol acetyltransferase reporter gene produced a maximal Et-1 promoter activity after undergoing strain for 6 h, whereas pretreatment with catalase decreased this activity. BAECs cotransfected with a dominant negative mutant of Ras (RasN17), Raf-1 (Raf301), or catalytically inactive mutant of extracellular signal-regulated kinase (mERK2) had inhibited strain-induced Et-1 promoter activity, indicating the Ras/Raf/ERK pathway was involved; moreover, ERK phosphorylation was induced in ECs which were strained. This strain-activated ERK phosphorylation was attenuated in the presence of catalase. Functional analysis of the Et-1 promoter with site-directed mutagenesis indicates that the activator protein-1 (AP-1) binding site had to be within 143 base-pairs upstream of transcription initiation site for strain-induced promoter activity. Pretreatment of ECs with catalase also decreased the strain-induced promoter activity in the minimal construct (-143 bp). Our data demonstrate that strain-induced Et-1 gene expression is modulated by ROS via Ras/Raf/ERK signaling pathway, and indicate the responsiveness of the AP-1 binding site for strain-induced Et-1 expression.
J Mol Cell Cardiol 2001 Oct
PMID:Reactive oxygen species mediate cyclic strain-induced endothelin-1 gene expression via Ras/Raf/extracellular signal-regulated kinase pathway in endothelial cells. 1160 23

Ischemic preconditioning results in an immediate phase of protection against lethal ischemia/reperfusion injury that is comprised of both irreversible necrosis and programmed cell death, apoptosis. We hypothesized that preconditioning may activate putative anti-apoptotic pathways, through the induction of either phosphatidyl inositol 3-OH kinase (PI3 kinase) or p42/p44 extracellular receptor kinase, attenuating total cell death. Isolated perfused rat hearts were preconditioned with two cycles of 5 min ischemia and 10 min reperfusion. Then they were frozen for Western blot analysis or subjected to 35 min regional ischemia and 120 min reperfusion prior to infarct size assessment. Selective PI3 kinase inhibitors, wortmannin (W, 100 n M) and LY294002 (LY, 15 microM) and the p42/p44 inhibitor, PD 98059 (PD, 10 and 50 microM), were individually infused during the preconditioning protocol. One further group of hearts received both inhibitors (W and PD). The results were expressed as percentage of infarction within the risk zone. Inhibition of PI3 kinase by either W or LY partially abrogated the infarct sparing effect of ischemic preconditioning (I/R%: 44.6+/-2.7 in C, 17.6+/-2.0 in IP, vs 32.2+/-4.2 in W, and 30.9+/-2.6 in LY, P<0.05). Inhibition of ERK phosphorylation however, had no significant effect upon infarct size reduction (17.6+/-2.0 in ischemic preconditioning vs 21.4+/-3.0 in IP+10 microM PD and 15.2+/-1.4 in IP+50 microM PD, P>0.05). Western blot analysis confirmed that PD abrogated the phosphorylation of p42/p44 and LY the phosphorylation of AKT. Combined inhibition with PD+W failed to further attenuate protection (27.6+/-1.3%, P>0.1). These data appear to demonstrate that the PI3 kinase, but not the p42/p44 cascade, is implicated in early ischemic preconditioning.
J Mol Cell Cardiol 2002 Jun
PMID:PI3 kinase and not p42/p44 appears to be implicated in the protection conferred by ischemic preconditioning. 1205 53

We have previously reported that beta-adrenergic receptor (beta-AR) stimulation promotes apoptosis in adult ventricular myocytes through PKCepsilon-mediated suppression of ERK. In this study, we investigated differential effects of beta-AR subtypes on this signal pathway. The apoptosis induced by the non-specific beta-AR agonist isoproterenol was largely blocked by the beta(1)-selective antagonist CGP 20712A, but not by the beta(2)-selective antagonist ICI 118551. A pro-apoptotic effect of beta(1)-AR was also blocked by the PKA inhibitor H89, while the protein kinase A (PKA) activators forskolin and dibutyryl-cAMP both induced apoptosis. These results indicate that beta(1)-AR-mediated PKA activation is largely responsible for the apoptosis induced by beta-AR in adult rat cardiac myocytes. This conclusion was also supported by the finding that PKA was preferentially activated by beta(1)-AR over beta(2)-AR. beta(2)-AR selectively induced anti-apoptotic ERK activation in the presence of PKCepsilon suppression, and this ERK activation was sensitive to pertussis toxin. PKCepsilon itself as well as Akt, the other anti-apoptotic factor were activated by both beta-AR subtypes. Thus, beta(1)-AR induces pro-apoptotic signals mainly through PKA activation. In contrast, beta(2)-AR is linked to Gi-mediated ERK activation, which is involved in the anti-apoptotic pathway, and is regulated by PKCepsilon. Therefore, our findings suggest a rather complex role for beta-AR subtypes in the regulation of apoptosis in adult ventricular myocytes.
J Mol Cell Cardiol 2002 Jul
PMID:Subtype specific roles of beta-adrenergic receptors in apoptosis of adult rat ventricular myocytes. 1209 21

Activation of the local and systemic renin-angiotensin system is directly and indirectly involved in mechanisms of vascular remodeling during chronic hypertension. This study investigated the effect of angiotensin II (AII) on rat vascular smooth muscle cell (VSMC) migration towards platelet-derived growth factor-BB (PDGF-BB) in vitro. Pre-treatment with AII (1 microM) for 48 or 72 h induced a significant increase in PDGF-BB-directed migration by 77 +/- 21 % and 58 +/- 24 %, respectively (both p < 0.01). This effect was concentration dependent and inhibited by the selective angiotensin receptor type I (AT(1)) blocker DUP 753. PDGF-directed migration of VSMCs was significantly inhibited by antibodies against beta(3)-and beta(5)-integrins, indicating an important role of these integrins in VSMC migration. However, AII augmented migration was not accompanied by an increased expression of beta(3)- and beta(5)-integrin mRNA and protein levels in VSMCs. Inhibition of the mitogen-activated protein kinase ERK 1/2 with PD 98059 (30 microM) completely abolished the effect of AII on PDGF-BB-directed VSMC migration (p < 0.01). The proline-rich tyrosine kinase 2 (Pyk2) and focal adhesion kinase (FAK) are cytoskeleton-associated protein kinases participating in integrin-dependent signaling. Therefore, expression and phosphorylation of these kinases was determined 48 h after AII treatment, revealing a significant increase in Pyk2 and FAK protein levels (up to 2-fold, both p < 0.05) and increased phosphorylation of Pyk2 (2-fold, p < 0.05) and ERK 1/2 (4-fold, p < 0.05) as compared to controls. Furthermore, immunofluorescence and Western blot analysis demonstrated a translocation of Pyk2 from the plasma membrane to the cytosol, as well as a perinuclear enrichment of ERK 1/2 protein 48 h after AII treatment. In conclusion, our data suggest that changes in the levels of Pyk2 and ERK 1/2 phosphorylation, responsible for integrin-dependent signaling, as well as their subcellular translocation are important for the enhanced chemotactic response of VSMCs after AII pre-treatment.
Basic Res Cardiol 2002 Jul
PMID:Angiotensin II-augmented migration of VSMCs towards PDGF-BB involves Pyk2 and ERK 1/2 activation. 1211 Oct 44

The aim of this prospective, randomized study was to investigate the effect of pretreatment with two different intracellular calcium-lowering drugs (verapamil and metoprolol) on recovery from atrial effective refractory period (AERP) shortening after internal electrical cardioversion (EC) of persistent atrial fibrillation (AF) in patients on amiodarone. Twenty-one patients on amiodarone for at least 30 days were referred to our hospital for internal EC of a persistent AF refractory to external EC. They were randomized to receive only amiodarone (group AMI, n=7), or amiodarone and verapamil 240 mg/day (group VER, n=7), or amiodarone and metoprolol 100 mg/day (group MET, n=7). Left AERP was measured 10 min and 24 h after EC. AERP was also determined in 13 controls. The AERP after 10 min was significantly shorter in group AMI (201 (31) ms, P<0.02) and group MET (203 (34) ms, P<0.03) than in controls (249 (45) ms), but not in group VER (237 (51) ms, P=NS). The AERP after 24 h was still significantly shorter in group AMI (204 (38) ms, P<0.04) than in controls, but not in group MET (225 (52) ms, P=NS) or in group VER (290 (36) ms, P=NS). Pretreatment with amiodarone and verapamil prevents AERP shortening, while pretreatment with amiodarone and metoprolol only accelerated AERP recovery.
Int J Cardiol 2003 Feb
PMID:Effects of verapamil and metoprolol on recovery from atrial electrical remodeling after cardioversion of long-lasting atrial fibrillation. 1255 36

Increased lipid oxidative stress has been recently implicated in the pathogenesis of coronary artery spasm. Small, dense LDL with high susceptibility to oxidation may be linked to the genesis of coronary vasospasm. The relative migratory distance of the predominant densitometric peak of LDL from that of VLDL to that of HDL in a 3% polyacrylamide gel electrophoresis was determined as a measure of LDL particle size in 49 patients with coronary spastic angina (CSA), in 56 patients with stable effort angina and a significant coronary artery stenosis (SEA) and also in 40 control subjects without coronary artery disease (Control). The incidence of detection of small, dense LDL (particle diameter <25.5 nm) or a relative migratory distance above 0.36 was significantly higher in CSA (57%) and also in SEA (39%) than in Control (20%). In SEA, a significantly higher serum level of triglyceride was noted in the subgroup with the small, dense LDL as compared with the subgroup without. In contrast, in CSA, the serum level of triglyceride was not significantly different between the subgroups with and without the small, dense LDL, although significantly lower serum levels of both HDL-cholesterol and alpha-tocopherol were noted in the former. In 16 patients of CSA, the detection of the small, dense LDL was significantly decreased after a >6-month angina-free period (69-->31%). We conclude that patients with coronary spastic angina had smaller LDL particles, associated not with hypertriglyceridemia but low serum levels of both HDL-cholesterol and vitamin E. Dyslipidemia with small, dense LDL may be related to the genesis of coronary vasospasm.
Int J Cardiol 2003 Feb
PMID:Low density lipoprotein particles are small in patients with coronary vasospasm. 1255 40

Vascular endothelial growth factor (VEGF), produced predominantly by endothelial cells, is involved in angiogenesis and mitogenesis. Myofibroblasts (myoFb) are phenotypically transformed fibroblast-like cells found at the site of myocardial infarction. Since myoFb play a role in tissue repair/remodeling at the site of infarction, and express endothelin and angiotensin II (AngII), it was interesting to investigate whether myoFb express VEGF and its receptors de novo, and if the expression is influenced by vasoactive peptides. Primary cultures of myoFb were isolated from 4-week-old adult rat heart infarct were used in this study. Semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR), utilizing primers designed to amplify known isoforms of VEGF revealed expression of two predominant forms, VEGF120 and VEGF164 and northern blot hybridization detected VEGF mRNA of 4.5 kb. VEGF actions are mediated via two major receptors, Flt-1 and KDR, and hence the expression of these receptors was investigated. Flt-1 and KDR expression in myoFb was detected by RT-PCR, RNA transcripts were confirmed by northern blot hybridization while western blot confirmed the presence of VEGF, Flt-1 and KDR proteins in myoFb. In this study AngII upregulated VEGF and Flt-1 expression in myoFb, but not KDR; this was mediated predominantly by AT1-receptor. We report for the first time that cardiac myoFb, isolated from the site of infarction express VEGF, its receptors, Flt-1 and KDR, with modulation of VEGF and Flt-1 expression by AngII. Thus, VEGF may contribute to tissue remodeling and angiogenesis at the site of infarction in an autocrine manner.
J Mol Cell Cardiol 2003 Mar
PMID:Cardiac myofibroblasts: a novel source of vascular endothelial growth factor (VEGF) and its receptors Flt-1 and KDR. 1267 42


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