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001-es BibID:	BIBFORM040582
Első szerző:	Velden, Jolanda, van der
Cím:	Increased Ca2+-sensitivity of the contractile apparatus in end-stage human heart failure results from altered phosphorylation of contractile proteins / van der Velden J., Papp Z., Zaremba R., Boontje N. M., de Jong J. W., Owen V. J., Burton P. B., Goldmann P., Jaquet K., Stienen G. J.
Dátum:	2003
ISSN:	0008-6363
Megjegyzések:	OBJECTIVE: The alterations in contractile proteins underlying enhanced Ca(2+)-sensitivity of the contractile apparatus in end-stage failing human myocardium are still not resolved. In the present study an attempt was made to reveal to what extent protein alterations contribute to the increased Ca(2+)-responsiveness in human heart failure. METHODS: Isometric force and its Ca(2+)-sensitivity were studied in single left ventricular myocytes from non-failing donor (n=6) and end-stage failing (n=10) hearts. To elucidate which protein alterations contribute to the increased Ca(2+)-responsiveness isoform composition and phosphorylation status of contractile proteins were analysed by one- and two-dimensional gel electrophoresis and Western immunoblotting. RESULTS: Maximal tension did not differ between myocytes obtained from donor and failing hearts, while Ca(2+)-sensitivity of the contractile apparatus (pCa(50)) was significantly higher in failing myocardium (deltapCa(50)=0.17). Protein analysis indicated that neither re-expression of atrial light chain 1 and fetal troponin T (TnT) nor degradation of myosin light chains and troponin I (TnI) are responsible for the observed increase in Ca(2+)-responsiveness. An inverse correlation was found between pCa(50) and percentage of phosphorylated myosin light chain 2 (MLC-2), while phosphorylation of MLC-1 and TnT did not differ between donor and failing hearts. Incubation of myocytes with protein kinase A decreased Ca(2+)-sensitivity to a larger extent in failing (deltapCa(50)=0.20) than in donor (deltapCa(50)=0.03) myocytes, abolishing the difference in Ca(2+)-responsiveness. An increased percentage of dephosphorylated TnI was found in failing hearts, which significantly correlated with the enhanced Ca(2+)-responsiveness.
Tárgyszavak:	Orvostudományok Klinikai orvostudományok idegen nyelvű folyóiratközlemény külföldi lapban
Megjelenés:	Cardiovascular Research. - 57 : 1 (2003), p. 37-47. -
További szerzők:	Papp Zoltán (1965-) (kardiológus, élettanász) Zaremba, Ruud Boontje, Nicky M. de Jong, J. W. Owen, V. J. Burton, P. B. Goldmann, P. Jaquet, Kai Stienen, Ger J. M.
Internet cím:	Intézményi repozitóriumban (DEA) tárolt változat DOI
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