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SERCA2a activity correlates with the force-frequency relationship in human myocardium
Ist Teil von
American journal of physiology. Heart and circulatory physiology, 2000-06, Vol.278 (6), p.H1924-H1932
Ort / Verlag
United States
Erscheinungsjahr
2000
Link zum Volltext
Quelle
Free E-Journal (出版社公開部分のみ）
Beschreibungen/Notizen
1 Laboratory of Muscle Research and Molecular
Cardiology, Klinik III für Innere Medizin;
2 Department of Cardiac and Thoracic Surgery; and
3 Department of Anatomy, Universität zu
Köln, 50924 Cologne, Germany
The present investigation addresses whether protein
expression and function of sarco(endo)plasmic reticulum
Ca 2+ -ATPase (SERCA2a) and phospholamban (PLB) correlate in
failing and nonfailing human myocardium. SERCA2a activity and protein expression, PLB phosphorylation, and the force-frequency relationship (FFR) have been determined in right atrium (RA) and left ventricle (LV)
from nonfailing (NF, n = 12) and terminally failing
[dilated cardiomyopathy (DCM), n = 12] human
hearts. Only in LV of DCM hearts was SERCA2a activity significantly
decreased [maximal turnover rate ( V max ) = 196 ± 11 and 396 ± 30 nmol · mg 1 · min 1
in LV and RA, respectively], whereas protein expression of
SERCA2a in the different chambers was unchanged in NF (3.9 ± 0.3 and
3.2 ± 0.4 densitometric units in LV and RA, respectively) and DCM hearts (4.8 ± 0.8 and 3.4 ± 0.1 densitometric units in LV and RA,
respectively). Phosphorylation of PLB was higher in LV than in RA in NF
(Ser 16 : 180.5 ± 19.0 vs. 56.8 ± 6.0 densitometric
units; Thr 17 : 174.6 ± 11.2 vs. 37.4 ± 8.9 densitometric
units) and DCM hearts (Ser 16 : 132.0 ± 5.4 vs. 22.4 ± 3.5 densitometric units; Thr 17 : 131.2 ± 10.9 vs. 9.2 ± 2.4 densitometric units). SERCA2a function, but not protein expression,
correlated well with the functional parameters of the FFR in DCM and NF
human hearts. Regulation of SERCA2a function depends on the
phosphorylation of PLB at Ser 16 and Thr 17 .
However, direct SERCA2a regulation might also be affected by an unknown mechanism.
heart failure; phospholamban phosphorylation; sarco(endo) plasmic
reticulum calcium-adenosine 5'-triphosphatase