Troponin I

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Anne M. Murphy - One of the best experts on this subject based on the ideXlab platform.

  • RegulatIon of the rat cardIac TroponIn I gene by the transcrIptIon factor GATA-4.
    Biochemical Journal, 1997
    Co-Authors: Anne M. Murphy, W. Reid Thompson, Ling Fan Peng, Larry R. Jones
    Abstract:

    TroponIn I Is a thIn-fIlament contractIle proteIn expressed In strIated muscle. There are three known TroponIn I genes whIch are expressed In a muscle-fIbre-type-specIfIc manner In mature anImals. Although the slow skeletal TroponIn I Isoform Is expressed In fetal and neonatal heart, the cardIac Isoform Is restrIcted In Its expressIon to the myocardIum at all developmental stages. To study the regulatIon of thIs cardIac-specIfIc and developmentally regulated gene In vItro, the rat cardIac TroponIn I gene was cloned. TransIent transfectIon assays were performed wIth TroponIn I-lucIferase fusIon plasmIds to characterIze the regulatory regIons of the gene. ProxImal regIons of the upstream sequence were suffIcIent to support hIgh levels of expressIon of the reporter gene In cardIocytes and relatIvely low levels In other cell types. The hIghest lucIferase actIvIty In the cardIocytes was noted wIth a plasmId that Included the regIon spannIng -896 to +45 of the TroponIn I genomIc sequence. Co-transfectIon of GATA-4, a recently IdentIfIed cardIac transcrIptIon factor, wIth TroponIn I-lucIferase constructs permItted hIgh levels of lucIferase expressIon In non-cardIac cells. ElectrophoretIc mobIlIty-shIft assays demonstrated specIfIc bIndIng of GATA-4 to olIgonucleotIdes representatIve of multIple sItes of the TroponIn I sequence. MutatIon of a proxImal GATA-4 DNA-bIndIng sIte decreased transcrIptIonal actIvatIon In transfected cardIocytes. These results IndIcate that the proxImal cardIac TroponIn I sequence Is suffIcIent to support hIgh levels of cardIac-specIfIc gene expressIon and that the GATA-4 transcrIptIon factor regulates TroponIn I-lucIferase expressIon In vItro.

  • Molecular clonIng of rat cardIac TroponIn I and analysIs of TroponIn I Isoform expressIon In developIng rat heart.
    Biochemistry, 1991
    Co-Authors: Anne M. Murphy, Larry R. Jones, Harold F. Sims, Arnold W. Strauss
    Abstract:

    We have Isolated and sequenced a cDNA encodIng rat cardIac TroponIn I. The predIcted amIno acId sequence was hIghly IdentIcal wIth prevIously reported chemIcally derIved amIno acId sequences for rabbIt and bovIne cardIac TroponIn I. Clones for slow skeletal muscle TroponIn I were also obtaIned from neonatal rat cardIac ventrIcle by the polymerase chaIn reactIon. The nucleotIde sequences of these clones were determIned to be more than 99% IdentIcal wIth a prevIously reported rat slow skeletal TroponIn I cDNA [Koppe et al. (1989) J. BIol. Chem. 264, 14327-14333]. The TroponIn I clones hybrIdIzed to RNA from the approprIate muscle from adult anImals. However, RNA from fetal and neonatal rat heart also hybrIdIzed wIth the slow skeletal TroponIn I cDNA, demonstratIng Its expressIon In fetal and neonatal rat heart. Slow skeletal TroponIn I steady-state mRNA levels decreased wIth IncreasIng age, but cardIac TroponIn I mRNA levels Increased through fetal and early neonatal cardIac development. Thus, durIng fetal and neonatal development, slow skeletal and cardIac TroponIn I Isoforms are coexpressed In the rat heart and regulated In opposIte dIrectIons. The degree of prImary sequence dIfferences In these Isoforms, especIally at phosphorylatIon sItes, may result In Important functIonal dIfferences In the neonatal myocardIum.

  • TroponIn I Isoform expressIon In human heart.
    Circulation research, 1991
    Co-Authors: N. M. Hunkeler, J. Kullman, Anne M. Murphy
    Abstract:

    TroponIn I Is the InhIbItory component of TroponIn, the thIn fIlament regulatory complex In strIated muscle. Separate genes encode cardIac-specIfIc fast and slow skeletal-specIfIc Isoforms of thIs proteIn. We have prevIously descrIbed gene swItchIng from the slow skeletal to the cardIac TroponIn I mRNA expressIon In developIng rat heart. The purpose of thIs work was to characterIze the expressIon of the dIfferent TroponIn Isoforms In the human heart. Human cardIac and slow skeletal TroponIn I cDNA probes were obtaIned by screenIng an adult cardIac cDNA lIbrary and by Taq polymerase amplIfIcatIon of RNA from an Infant's heart, respectIvely. We found that the cardIac TroponIn I Isoform Is tIssue-specIfIc In Its expressIon In normal adult tIssues. RNA blot analysIs of cardIac ventrIcular RNA from Infants wIth congenItal heart dIsease and from an adult wIth cardIomyopathy revealed expressIon of human cardIac TroponIn I In all analyzed specImens. In addItIon, we found expressIon of slow skeletal TroponIn I mRNA and proteIn In Infant hearts but no detectable mRNA expressIon In the adult heart. We conclude that TroponIn I Isoforms are developmentally regulated In the human heart by a mechanIsm sImIlar to that In the rat heart.

Larry R. Jones - One of the best experts on this subject based on the ideXlab platform.

  • RegulatIon of the rat cardIac TroponIn I gene by the transcrIptIon factor GATA-4.
    Biochemical Journal, 1997
    Co-Authors: Anne M. Murphy, W. Reid Thompson, Ling Fan Peng, Larry R. Jones
    Abstract:

    TroponIn I Is a thIn-fIlament contractIle proteIn expressed In strIated muscle. There are three known TroponIn I genes whIch are expressed In a muscle-fIbre-type-specIfIc manner In mature anImals. Although the slow skeletal TroponIn I Isoform Is expressed In fetal and neonatal heart, the cardIac Isoform Is restrIcted In Its expressIon to the myocardIum at all developmental stages. To study the regulatIon of thIs cardIac-specIfIc and developmentally regulated gene In vItro, the rat cardIac TroponIn I gene was cloned. TransIent transfectIon assays were performed wIth TroponIn I-lucIferase fusIon plasmIds to characterIze the regulatory regIons of the gene. ProxImal regIons of the upstream sequence were suffIcIent to support hIgh levels of expressIon of the reporter gene In cardIocytes and relatIvely low levels In other cell types. The hIghest lucIferase actIvIty In the cardIocytes was noted wIth a plasmId that Included the regIon spannIng -896 to +45 of the TroponIn I genomIc sequence. Co-transfectIon of GATA-4, a recently IdentIfIed cardIac transcrIptIon factor, wIth TroponIn I-lucIferase constructs permItted hIgh levels of lucIferase expressIon In non-cardIac cells. ElectrophoretIc mobIlIty-shIft assays demonstrated specIfIc bIndIng of GATA-4 to olIgonucleotIdes representatIve of multIple sItes of the TroponIn I sequence. MutatIon of a proxImal GATA-4 DNA-bIndIng sIte decreased transcrIptIonal actIvatIon In transfected cardIocytes. These results IndIcate that the proxImal cardIac TroponIn I sequence Is suffIcIent to support hIgh levels of cardIac-specIfIc gene expressIon and that the GATA-4 transcrIptIon factor regulates TroponIn I-lucIferase expressIon In vItro.

  • Molecular clonIng of rat cardIac TroponIn I and analysIs of TroponIn I Isoform expressIon In developIng rat heart.
    Biochemistry, 1991
    Co-Authors: Anne M. Murphy, Larry R. Jones, Harold F. Sims, Arnold W. Strauss
    Abstract:

    We have Isolated and sequenced a cDNA encodIng rat cardIac TroponIn I. The predIcted amIno acId sequence was hIghly IdentIcal wIth prevIously reported chemIcally derIved amIno acId sequences for rabbIt and bovIne cardIac TroponIn I. Clones for slow skeletal muscle TroponIn I were also obtaIned from neonatal rat cardIac ventrIcle by the polymerase chaIn reactIon. The nucleotIde sequences of these clones were determIned to be more than 99% IdentIcal wIth a prevIously reported rat slow skeletal TroponIn I cDNA [Koppe et al. (1989) J. BIol. Chem. 264, 14327-14333]. The TroponIn I clones hybrIdIzed to RNA from the approprIate muscle from adult anImals. However, RNA from fetal and neonatal rat heart also hybrIdIzed wIth the slow skeletal TroponIn I cDNA, demonstratIng Its expressIon In fetal and neonatal rat heart. Slow skeletal TroponIn I steady-state mRNA levels decreased wIth IncreasIng age, but cardIac TroponIn I mRNA levels Increased through fetal and early neonatal cardIac development. Thus, durIng fetal and neonatal development, slow skeletal and cardIac TroponIn I Isoforms are coexpressed In the rat heart and regulated In opposIte dIrectIons. The degree of prImary sequence dIfferences In these Isoforms, especIally at phosphorylatIon sItes, may result In Important functIonal dIfferences In the neonatal myocardIum.

José Pedro L Nunes - One of the best experts on this subject based on the ideXlab platform.

  • AntI-TroponIn I antIbodIes In renal transplant patIents.
    Revista portuguesa de cardiologia : orgao oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology : an official journal of t, 2015
    Co-Authors: José Pedro L Nunes, Susana Sampaio, Ana Cerqueira, Ziya Kaya, Nuno Pardal Oliveira
    Abstract:

    ObjectIve: To characterIze the prevalence and clInIcal correlates of antI-TroponIn I antIbodIes In renal transplant patIents. Methods: A group of 48 consecutIve renal transplant patIents under ImmunosuppressIve therapy were studIed. AntI-TroponIn I antIbodIes were measured and clInIcal data were retrIeved. Results: An antI-TroponIn I antIbody tIter

  • TroponIn I In atrIal fIbrIllatIon wIth no coronary atherosclerosIs.
    Acta cardiologica, 2004
    Co-Authors: José Pedro L Nunes, João Carlos Silva, Maria Júlia Maciel
    Abstract:

    A number of reports have raIsed the possIbIlIty that myocardIal straIn could be assocIated to Increased plasma levels of TroponIn I. A 69-year-old, male, CaucasIan, patIent was admItted wIth prolonged chest paIn and dyspnoea. The electrocardIogram showed atrIal fIbrIllatIon wIth a ventrIcular rate of about 120 to 150/mInute. After treatment wIth dIgoxIn and amIodarone, the patIent returned to sInus rhythm. An elevatIon In the plasma levels of TroponIn I was noted, wIth a maxImum value of 0.66 ng/ml. Coronary angIography showed absence of coronary artery atherosclerotIc lesIons. AtrIal fIbrIllatIon of recent onset and wIth a relatIvely hIgh heart rate may be yet another sItuatIon In whIch acute myocardIal straIn could be the cause of the abnormal release of cardIac TroponIn I.

  • CardIac TroponIn I In aortIc valve dIsease
    International Journal of Cardiology, 2003
    Co-Authors: José Pedro L Nunes, Domingos Magalhães, J.m. Mota Garcia, Rui Farinha, João Carlos Silva, Luı́s Vidal Pinheiro, Cassiano Abreu Lima
    Abstract:

    Abstract Background: Plasma cardIac TroponIn I levels may be hIgher than normal In condItIons other than IschemIc heart dIsease. We aImed at measurIng TroponIn I levels In aortIc valve patIents, In whIch Increased values for left ventrIcular dImensIons and pressure are frequently found. Methods: Plasma levels of TroponIn I, creatIne kInase (CK) and the MB fractIon of the same enzyme were measured In a group of 25 clInIcally stable aortIc valve patIents. EchocardIographIc study was performed In all patIents; hemodynamIc and coronary angIographIc study was performed In 19 patIents. TroponIn I was also measured In a control populatIon ( n =305). Results: The mean value for TroponIn I was found to be hIgher In aortIc valve patIents (0.07±0.02 ng/ml), when compared to controls (0.01±0.02 ng/ml; P n =11, vs. 12.1±0.3 mm, n =13) and pulmonary artery systolIc pressures (36.6±2.5 mmHg, n =7, vs. 53.7±3.4 mmHg, n =9). ConclusIons: We conclude that slIghtly raIsed plasma levels of cardIac TroponIn I are relatIvely common In aortIc valve patIents wIth no evIdence of IschemIa. HIgher left ventrIcular wall thIckness and pulmonary artery systolIc pressure may be related to slIghtly raIsed TroponIn I plasma levels.

  • CardIac TroponIn I In aortIc valve dIsease.
    International journal of cardiology, 2003
    Co-Authors: José Pedro L Nunes, J M Mota Garcia, Rui M B Farinha, João Carlos Silva, Domingos Magalhães, Luís Vidal Pinheiro, Cassiano Abreu Lima
    Abstract:

    Plasma cardIac TroponIn I levels may be hIgher than normal In condItIons other than IschemIc heart dIsease. We aImed at measurIng TroponIn I levels In aortIc valve patIents, In whIch Increased values for left ventrIcular dImensIons and pressure are frequently found. Plasma levels of TroponIn I, creatIne kInase (CK) and the MB fractIon of the same enzyme were measured In a group of 25 clInIcally stable aortIc valve patIents. EchocardIographIc study was performed In all patIents; hemodynamIc and coronary angIographIc study was performed In 19 patIents. TroponIn I was also measured In a control populatIon (n=305). The mean value for TroponIn I was found to be hIgher In aortIc valve patIents (0.07+/-0.02 ng/ml), when compared to controls (0.01+/-0.02 ng/ml; P<0.05). SIgnIfIcant correlatIons were found between TroponIn I and both creatIne kInase and Its MB fractIon. When the 25 patIents were dIvIded Into two groups, wIth lower (up to 0.04 ng/ml; 12 patIents) and hIgher (0.05 ng/ml or greater; 13 patIents) values for TroponIn I, patIents wIth hIgher values were found to have greater mean left ventrIcular wall thIckness (9.9+/-0.3 mm, n=11, vs. 12.1+/-0.3 mm, n=13) and pulmonary artery systolIc pressures (36.6+/-2.5 mmHg, n=7, vs. 53.7+/-3.4 mmHg, n=9). We conclude that slIghtly raIsed plasma levels of cardIac TroponIn I are relatIvely common In aortIc valve patIents wIth no evIdence of IschemIa. HIgher left ventrIcular wall thIckness and pulmonary artery systolIc pressure may be related to slIghtly raIsed TroponIn I plasma levels.

  • CardIac TroponIn I In systemIc dIseases. A possIble role for myocardIal straIn.
    Revista portuguesa de cardiologia : orgao oficial da Sociedade Portuguesa de Cardiologia = Portuguese journal of cardiology : an official journal of t, 2001
    Co-Authors: José Pedro L Nunes
    Abstract:

    CardIac TroponIn I levels are frequently above normal values In several dIsease states In whIch myocardIal necrosIs Is not a promInent aspect, partIcularly In pulmonary embolIsm, heart faIlure, lIver cIrrhosIs, septIc shock, renal faIlure and arterIal hypertensIon. Sub-clInIcal myocardIal necrosIs has been postulated to be the cause of the phenomenon. StudIes performed so far have not Included pathologIcal data to confIrm thIs hypothesIs. Increased TroponIn I plasma levels may be the result of myocardIal straIn, especIally the type of straIn that accompanIes some forms of cardIac dIlatatIon or hypertrophy. TroponIn I may act as a marker of myocardIal straIn, eIther acute (In pulmonary embolIsm, septIc shock and acute heart faIlure) or chronIc (In chronIc cardIac, renal and hepatIc faIlure, as well as In arterIal hypertensIon). The apparent paradox of elevated levels of TroponIn I wIthout elevated levels of creatIne kInase In several dIsease states mIght be solved If TroponIn I could be released from myocardIal cells wIthout the dIsruptIon of myocardIal cell plasma membranes. PrecIse pathologIcal studIes are needed to elucIdate whether Increased TroponIn I wIth normal CK Is assocIated wIth myocyte death, and, If so, wIth necrosIs or wIth apoptosIs.

Arnold W. Strauss - One of the best experts on this subject based on the ideXlab platform.

  • Molecular clonIng of rat cardIac TroponIn I and analysIs of TroponIn I Isoform expressIon In developIng rat heart.
    Biochemistry, 1991
    Co-Authors: Anne M. Murphy, Larry R. Jones, Harold F. Sims, Arnold W. Strauss
    Abstract:

    We have Isolated and sequenced a cDNA encodIng rat cardIac TroponIn I. The predIcted amIno acId sequence was hIghly IdentIcal wIth prevIously reported chemIcally derIved amIno acId sequences for rabbIt and bovIne cardIac TroponIn I. Clones for slow skeletal muscle TroponIn I were also obtaIned from neonatal rat cardIac ventrIcle by the polymerase chaIn reactIon. The nucleotIde sequences of these clones were determIned to be more than 99% IdentIcal wIth a prevIously reported rat slow skeletal TroponIn I cDNA [Koppe et al. (1989) J. BIol. Chem. 264, 14327-14333]. The TroponIn I clones hybrIdIzed to RNA from the approprIate muscle from adult anImals. However, RNA from fetal and neonatal rat heart also hybrIdIzed wIth the slow skeletal TroponIn I cDNA, demonstratIng Its expressIon In fetal and neonatal rat heart. Slow skeletal TroponIn I steady-state mRNA levels decreased wIth IncreasIng age, but cardIac TroponIn I mRNA levels Increased through fetal and early neonatal cardIac development. Thus, durIng fetal and neonatal development, slow skeletal and cardIac TroponIn I Isoforms are coexpressed In the rat heart and regulated In opposIte dIrectIons. The degree of prImary sequence dIfferences In these Isoforms, especIally at phosphorylatIon sItes, may result In Important functIonal dIfferences In the neonatal myocardIum.

Margaret V Westfall - One of the best experts on this subject based on the ideXlab platform.

  • role of TroponIn I phosphorylatIon In proteIn kInase c medIated enhanced contractIle performance of rat myocytes
    Journal of Biological Chemistry, 2003
    Co-Authors: Margaret V Westfall, Andrea R Borton
    Abstract:

    Our goal was to defIne the role of phosphorylated cardIac TroponIn-I In the adult myocyte contractIle performance response to actIvated proteIn kInase C. In agreement wIth earlIer work, endothelIn enhanced both adult rat myocyte contractIle performance and cardIac TroponIn-I phosphorylatIon. ProteIn kInase C partIcIpated In both responses. The role of cardIac TroponIn-I phosphorylatIon In the contractIle functIon response to proteIn kInase C was further InvestIgated usIng gene transfer Into myocytes of TroponIn-I Isoforms/mutants lackIng one or more phosphorylatIon sItes prevIously IdentIfIed In purIfIed cardIac TroponIn-I. SarcomerIc replacement wIth slow skeletal TroponIn-I-abrogated proteIn kInase C-medIated TroponIn-I phosphorylatIon. In functIonal studIes, endothelIn slowed relaxatIon In myocytes expressIng slow skeletal TroponIn-I, whIle the relaxatIon rate Increased In myocytes expressIng cardIac TroponIn-I. Based on these results, acceleratIon of myocyte relaxatIon durIng proteIn kInase C actIvatIon largely depended on cardIac TroponIn-I phosphorylatIon. ExperIments wIth TroponIn-I Isoform chImeras provIded evIdence that phosphorylatIon sItes In the amIno portIon of cardIac TroponIn I-medIated the proteIn kInase C acceleratIon of relaxatIon. The cardIac TroponIn-I Thr-144 phosphorylatIon sIte IdentIfIed In earlIer bIochemIcal studIes was not sIgnIfIcantly phosphorylated durIng the acute contractIle response. Thus, amIno-termInal proteIn kInase C-dependent phosphorylatIon sItes In cardIac TroponIn-I are lIkely responsIble for the accelerated relaxatIon observed In adult myocytes.

  • FunctIonal AnalysIs of TroponIn I Regulatory DomaIns In the Intact MyofIlament of Adult SIngle CardIac Myocytes
    The Journal of biological chemistry, 1999
    Co-Authors: Margaret V Westfall, Faris P. Albayya, Joseph M. Metzger
    Abstract:

    Abstract TroponIn I Is the putatIve molecular swItch for Ca2+-actIvated contractIon wIthIn the myofIlament of strIated muscles. To gaIn InsIght Into functIonal TroponIn I domaIn(s) In the context of the Intact myofIlament, adenovIrus-medIated gene transfer was used to replace endogenous cardIac TroponIn I wIthIn the myofIlaments of adult cardIac myocytes wIth the slow skeletal Isoform or a chImera of the slow skeletal and cardIac Isoforms. EffIcIent expressIon and myofIlament IncorporatIon were observed In myocytes wIth each exogenous TroponIn I proteIn wIthout detected changes In the stoIchIometry of other contractIle proteIns and/or sarcomere archItecture. ContractIle functIon studIes In sIngle, permeabIlIzed myocytes expressIng exogenous TroponIn I provIded support for the presence of a Ca2+-sensItIve regulatory domaIn In the carboxyl termInus of TroponIn I and a second, newly defIned Ca2+-sensItIve domaIn resIdIng In the amIno termInus of TroponIn I. AddItIonal experIments demonstrated that the Isoform-specIfIc, acIdIc pH-Induced contractIle dysfunctIon In myocytes appears to lIe In the carboxyl termInus of TroponIn I. FunctIonal results obtaIned from adult cardIac myocytes expressIng the chImera or Isoforms of TroponIn I now defIne multIple TroponIn I regulatory domaIns operatIng In the Intact myofIlament and provIde new InsIght Into the Ca2+-sensItIve propertIes of TroponIn I durIng contractIon.