Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Heart-specific inhibition of survival pathway gp130 was recently shown to sensitize transgenic mice towards stress stimuli, resulting in rapid onset of cardiac dilatation and heart failure. In order to identify further survival pathways we evaluated the role of transcription factor nuclear factor-kappa B (NF-kappa B) in tumour necrosis factor-alpha (TNF-alpha)-induced apoptosis of cardiomyocytes. TNF-alpha stimulation (10 ng/ml) of both H9c2 cells and primary cardiomyocytes isolated from neonatal Wistar rats resulted in rapid nuclear translocation of NF-kappa B complexes. The NF-kappa B complexes consisted of rel-proteins p50 and p65, as revealed by supershift analysis. Addition of proteasome inhibitor MG132 or adenoviral expression of a truncated I kappa B alpha (I kappa B Delta N) inhibited TNF-alpha-induced NF-kappa B nuclear translocation in a dose-dependent manner. Both neonatal cardiomyocytes and H9c2 cells were resistant to TNF-induced apoptosis. However, specific inhibition of NF-kappa B activation by Ad5-I kappa B alpha Delta N (MOI=50) or MG132 (5 microm) increased apoptosis as measured by subG1-assay (H9c2 cells) and annexin V binding/propidium iodide (neonatal cardiomyocytes, FACS-analysis: 7+/-2% to 26+/-5% annexin V positive/PI negative), respectively. TUNEL-assay double-stained with anti-alpha-sarcomeric actin confirmed apoptosis of neonatal cardiomyocytes. Furthermore, caspase-3 activation was increased by 52+/-7% in neonatal cardiomyocytes after TNF alpha+Ad5-I kappa B alpha Delta N compared to TNF alpha+Ad5-control treatment. Protein levels of hiAP1, hiAP2, x-iAP, bcl-2 and bcl-x(L) were neither downregulated by NF-kappa B inhibition nor upregulated by TNF-alpha stimulation. In summary, cardiomyocytes utilize transcription factor NF-kappa B to activate survival factors in the context of TNF-alpha stimulation. As locally increased levels of TNF-alpha have been detected in heart failure, NF-kappa B activity is essential for cellular homeostasis in the heart.
J Mol Cell Cardiol 2001 Jun
PMID:Effect of NF-kappa B Inhibition on TNF-alpha-induced apoptosis and downstream pathways in cardiomyocytes. 1144 25

Short duration exposure to cellular stresses have been shown to activate p38 mitogen-activated protein kinase (MAPK) in cultured rat ventricular cardiomyocytes and isolated perfused hearts; however, effects of chronic stress on p38 MAPK are not well understood. This study determined whether alterations in the p38 MAPK pathway occurred prior to end-stage human heart failure. The p38 MAPK alpha isoform was detectable in human cardiac tissue. However, carefully controlled analysis of protein and message in this study demonstrated an absence of the p38 MAPK beta -isoform. Low levels of message for the non-SB203580 sensitive p38 MAPK gamma and delta isoforms were also detected in both normal and failing human myocardium. Ischemic and idiopathic end-stage failing human hearts were compared to non-failing hearts for both p38 alpha MAPK protein level and total p38 MAPK activity. Western blotting techniques demonstrated no significant changes in total p38 alpha MAPK content. However, approximately 75% decreases in active/phosphorylated p38 MAPK (P<0.005) were observed in both ischemic and idiopathic failing hearts compared to non-failing hearts. In-gel kinase assays confirmed that activated p38 MAPK, detected by Western blotting, phosphorylated its potential downstream targets. When compared to non-failing hearts, approximately 46% decreases in p38 MAPK phosphorylation of mitogen-activated protein kinase-activated protein kinase-2 (MAPKAPK-2) were observed in ischemic and idiopathic failing hearts (P=0.03 and P=0.04 respectively). Active p38 MAPK was localized to sarcomeric structures in the cytosol of myocytes by confocal immunofluorescence microscopy. The correlation between decreased MAPKAPK-2 phosphorylation and loss of active p38 MAPK in failing human myocytes suggests that decreases in the activation of p38 MAPK alpha, the predominant cardiac isoform, occur prior to end-stage heart failure.
J Mol Cell Cardiol 2001 Aug
PMID:Decreased p38 MAPK activity in end-stage failing human myocardium: p38 MAPK alpha is the predominant isoform expressed in human heart. 1144 40

Hypertrophic terminally differentiated cardiac myocytes show increased sarcomeric organization and altered gene expression. Previously, we established a role for the nonreceptor tyrosine kinase Src in signaling cardiac myocyte hypertrophy. Here we report evidence that p130Cas (Cas) and focal adhesion kinase (FAK) regulate this process. In neonatal cardiac myocytes, tyrosine phosphorylation of Cas and FAK increased upon endothelin (ET) stimulation. FAK, Cas, and paxillin were localized in sarcomeric Z-lines, suggesting that the Z-line is an important signaling locus in these cells. Cas, alone or in cooperation with Src, modulated basal and ET-stimulated atrial natriuretic peptide (ANP) gene promoter activity, a marker of cardiac hypertrophy. Expression of the C-terminal focal adhesion-targeting domain of FAK interfered with localization of endogenous FAK to Z-lines. Expression of the Cas-binding proline-rich region 1 of FAK hindered association of Cas with FAK and impaired the structural stability of sarcomeres. Collectively, these results suggest that interaction of Cas with FAK, together with their localization to Z-lines, is critical to assembly of sarcomeric units in cardiac myocytes in culture. Moreover, expression of the focal adhesion-targeting and/or the Cas-binding proline-rich regions of FAK inhibited ANP promoter activity and suppressed ET-induced ANP and brain natriuretic peptide gene expression. In summary, assembly of signaling complexes that include the focal adhesion proteins Cas, FAK, and paxillin at Z-lines in the cardiac myocyte may regulate, either directly or indirectly, both cytoskeletal organization and gene expression associated with cardiac myocyte hypertrophy.
Mol Biol Cell 2001 Aug
PMID:Focal adhesion kinase and p130Cas mediate both sarcomeric organization and activation of genes associated with cardiac myocyte hypertrophy. 1151 17

Actin-containing microfilaments control cell shape, adhesion, and contraction. In striated muscle, alpha-actinin and other Z-disk proteins coordinate the organization and functions of actin filaments. In smooth muscle and nonmuscle cells, periodic structures termed dense bodies and dense regions, respectively, are thought to serve functions analogous to Z-discs. We describe here identification and characterization of human palladin, a protein expressed mainly in smooth muscle and nonmuscle and distributed along microfilaments in a periodic manner consistent with dense regions/bodies. Palladin contains three Ig-domains most homologous to the sarcomeric Z-disk protein myotilin. The N terminus includes an FPPPP motif recognized by the Ena-Vasp homology domain 1 domain in Ena/vasodilatator-stimulated phosphoprotein (VASP)/Wiscott-Aldrich syndrome protein (WASP) protein family. Cytoskeletal proteins with FPPPP motif target Ena/VASP/WASP proteins to sites of actin modulation. We identified palladin in a yeast two-hybrid search as an ezrin-associated protein. An interaction between palladin and ezrin was further verified by affinity precipitation and blot overlay assays. The interaction was mediated by the alpha-helical domain of ezrin and by Ig-domains 2-3 of palladin. Ezrin is typically a component of the cortical cytoskeleton, but in smooth muscle cells it is localized along microfilaments. These cells express palladin abundantly and thus palladin may be involved in the microfilament localization of ezrin. Palladin expression was up-regulated in differentiating dendritic cells (DCs), coinciding with major cytoskeletal and morphological alterations. In immature DCs, palladin localized in actin-containing podosomes and in mature DCs along actin filaments. The regulated expression and localization suggest a role for palladin in the assembly of DC cytoskeleton.
Mol Biol Cell 2001 Oct
PMID:Characterization of human palladin, a microfilament-associated protein. 1159 91

Tropomyosin, an essential component of the sarcomere, regulates muscle contraction through Ca(2+)-mediated activation. Familial hypertrophic cardiomyopathy (FHC) is caused by mutations in numerous cardiac sarcomeric proteins, including myosin heavy and light chains, actin, troponin T and I, myosin binding protein C, and alpha-tropomyosin. This study developed transgenic mouse lines that encode an FHC mutation in alpha-tropomyosin; this mutation is an amino acid substitution at codon 180 (Glu180Gly) which occurs in a troponin T binding region. Non-transgenic and control mice expressing wild-type alpha-tropomyosin demonstrate no morphological or physiological changes. Expression of exogenous mutant tropomyosin leads to a concomitant decrease in endogenous alpha-tropomyosin without altering the expression of other contractile proteins. Histological analysis shows that initial pathological changes, which include ventricular concentric hypertrophy, fibrosis and atrial enlargement, are detected within 1 month. The disease-associated changes progressively increase and result in death between 4 and 5 months. Physiological analyses of the FHC mice using echocardiography, work-performing heart analyses, and force measurements of cardiac myofibers, demonstrate dramatic functional differences in diastolic performance and increased sensitivity to calcium. This report demonstrates that mutations in alpha-tropomyosin can be severely disruptive of sarcomeric function, which consequently triggers a dramatic hypertrophic response that culminates in lethality.
J Mol Cell Cardiol 2001 Oct
PMID:A familial hypertrophic cardiomyopathy alpha-tropomyosin mutation causes severe cardiac hypertrophy and death in mice. 1160 24

Ion-channel beta-subunits are ancillary proteins that co-assemble with alpha-subunits to modulate gating kinetics and enhance stability of multimeric channel complexes. They provide binding sites for other regulatory proteins and are medically important as the targets of many pharmacological compounds. MinK is the beta-subunit of the slow activating component of the delayed rectifier potassium current (I(Ks)) channel, and associates with the alpha-subunit, KvLQT1. We report here that minK specifically interacts with the sarcomeric Z-line component, T-cap (also called telethonin). In vitro interaction studies indicated that the cytoplasmic domain of minK specifically binds to the sixteen C-terminal residues of T-cap; these residues are sufficient for its interaction with minK. Consistent with our in vitro studies, immunofluorescence staining followed by confocal analysis revealed that both minK and T-cap are localized within the Z-line region in cardiac muscle. Striated staining of minK was observed in non-washed, membrane-intact cardiac myofibrils, but not in well-washed, membrane-removed cardiac myofibrils, suggesting that minK localizes on T-tubular membranes surrounding the Z-line in the inner ventricular myocardium. Together with our previous data on the colocalization and interaction of T-cap with the N-terminus of the giant protein titin in the periphery of the Z-line, these data suggest that T-cap functions as an adapter protein to link together myofibrillar components with the membranous beta-subunit of the I(Ks) channel. We speculate that this interaction may contribute to a stretch-dependent regulation of potassium flux in cardiac muscle, providing a "mechano-electrical feedback" system.
J Mol Biol 2001 Nov 02
PMID:Specific interaction of the potassium channel beta-subunit minK with the sarcomeric protein T-cap suggests a T-tubule-myofibril linking system. 1169 3

Drosophila projectin is an extremely large protein found within the muscle sarcomeric unit, parallel with the actin and myosin filaments. Projectin has been suggested as the elastic component of C-filaments in insect indirect flight muscles, which is consistent with its localization from the Z band to the tip of the A band in these muscles. Here, we describe the completion of the projectin sequence analysis, which defines projectin as a 1 MDa protein, composed of 39 immunoglobulin and 39 fibronectin III domains. This analysis led also to the identification of a domain rich in the amino acids P, E, V and K within the NH(2) terminus of projectin. The length of the projectin PEVK-like region varies from 100 to 624 amino acid residues, following a complex pattern of alternative splicing events. PEVK domains were first identified in vertebrate titin and they have been associated with the elasticity of the protein. The PEVK-like domain of the projectin isoforms in indirect flight muscles may contribute to the elastic function of the C-filaments. The synchronous projectin isoforms contain a PEVK-like region, and the possible non-elastic function(s) of this domain in synchronous muscles are discussed.
J Mol Biol 2001 Nov 09
PMID:Alternative splicing of an amino-terminal PEVK-like region generates multiple isoforms of Drosophila projectin. 1170 60

We examined the intracellular signaling mechanism for tumor necrosis factor-alpha (TNF-alpha)-induced cardiac hypertrophy in isolated rat neonatal cardiomyocytes. TNF-alpha enhanced the expression of a kappa B-dependent reporter gene construct in a dose-dependent manner, which was transiently transfected in cardiomyocytes. Electrophoretic mobility shift assay demonstrated that TNF-alpha induced nuclear factor- kappa B (NF-kappa B)-specific DNA binding. Cultured cardiomyocytes were infected with a recombinant adenoviral vector expressing a degradation-resistant mutant of I kappa B alpha (AdI kappa B alpha 32/36A). The I kappa B alpha mutant suppressed NF-kappa B activation induced by TNF- alpha. In cardiomyocytes infected with AdI kappa B alpha 32/36A, TNF-alpha-induced hypertrophic responses, including increases in cell size, protein synthesis and atrial natriuretic factor production and enhancement of sarcomeric organization, were remarkably attenuated compared to the cells infected with an adenovirus expressing bacterial beta-galactosidase. Using a reactive oxygen species (ROS)-sensitive fluorescent dye, 2', 7'-dichlorofluorescin, we observed an increase in fluorescent signal in cardiomyocytes over time, upon addition of TNF-alpha. Preincubation of n-acetyl cysteine (NAC), an antioxidant, prior to TNF-alpha treatment, abolished TNF-alpha -induced ROS generation. NAC abolished TNF-alpha-induced NF-kappa B activation and hypertrophic responses. These findings indicated that TNF-alpha-induced cardiomyocyte hypertrophy is mediated through NF-kappa B activation via the generation of ROS.
J Mol Cell Cardiol 2002 Feb
PMID:Involvement of reactive oxygen species-mediated NF-kappa B activation in TNF-alpha-induced cardiomyocyte hypertrophy. 1185 62

Anthracyclines are among the most efficient drugs of cancer chemotherapy, but their use is limited by a significant risk of cardiotoxicity, which is still far from being understood. This study investigates whether impairment of mitochondrial creatine kinase (MtCK), a key enzyme in cellular energy metabolism, could be involved in anthracycline cardiotoxicity. We have analyzed the effects of three anthracyclines, doxorubicin, daunorubicin, and idarubicin, on two MtCK isoenzymes, sarcomeric/cardiac sMtCK and ubiquitous uMtCK, from human and chicken. Using surface plasmon resonance, gel filtration, and enzyme assays, we have quantified properties that are of basic importance for MtCK functioning in vivo: membrane binding, octameric state, and enzymatic activity. Anthracyclines significantly impaired all three properties with differences in dose-, time-, and drug-dependence. Membrane binding and enzymatic activity were already affected at low anthracycline concentrations (5-100 microM), indicating high clinical relevance. Effects on membrane binding were immediate, probably because of competitive binding of the drug to cardiolipin. In contrast, dissociation of MtCK octamers into dimers, enzymatic inactivation and cross-linking occurred only after hours to days. Different protection assays suggest that the deleterious effects were caused by oxidative damage, mainly affecting the highly susceptible MtCK cysteines, followed by generation of free oxygen radicals at higher drug concentrations. Enzymatic inactivation occurred mainly at the active site and involved Cys278, as indicated by experiments with protective agents and sMtCK mutant C278G. All anthracycline effects were significantly more pronounced for sMtCK than for uMtCK. These in vitro results suggest that sMtCK damage may play a role in anthracycline cardiotoxicity.
Mol Pharmacol 2002 Mar
PMID:Multiple interference of anthracyclines with mitochondrial creatine kinases: preferential damage of the cardiac isoenzyme and its implications for drug cardiotoxicity. 1185 31

GATA-4 transcription factor is required for normal cardiac development. However, it is unknown whether GATA-4 is an essential mediator of hypertrophic responses in the heart. Rat B-type natriuretic peptide (BNP) gene promoter contains a region of two adjacent GATA binding sites (between -68 and -97) with high affinity for GATA-4. In order to block GATA-4 dependent signaling in cultured neonatal rat ventricular myocytes we administered a synthetic 30-bp phosphorothioated double-stranded DNA complementary to the rat BNP promoter region (between -68 and -97) as a "decoy" cis-element to bind GATA-4. GATA decoy oligodeoxynucleotide treatment of cardiomyocytes blocked GATA-4 DNA binding activity in electrophoretic mobility shift analysis and decreased baseline expression of cardiac natriuretic peptides and GATA-dependent promoter activity. In contrast, blocked GATA-4 DNA binding did not prevent endothelin-1 or phenylephrine induced expression of cardiac natriuretic peptides. Mutation of GATA binding sites at -80 and -91 rat BNP promoter downregulated baseline but did not affect endothelin-1 or angiotensin II induced promoter activity. Additively, GATA decoy oligodeoxynucleotide treatment was insufficient to block endothelin-1 induced activation of protein synthesis or sarcomeric protein assembly. In conclusion, a targeted disruption of GATA-4 DNA binding activity is insufficient to prevent hypertrophic agonist induced responses of ventricular myocytes.
J Mol Med (Berl) 2002 Jan
PMID:Decoy oligonucleotide characterization of GATA-4 transcription factor in hypertrophic agonist induced responses of cardiac myocytes. 1186 25


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