GONUTS has been updated to MW1.31 Most things seem to be working but be sure to report problems.

Have any questions? Please email us at ecoliwiki@gmail.com

PMID:9887021

From GONUTS
Jump to: navigation, search
Citation

Ji, Y, Loukianov, E, Loukianova, T, Jones, LR and Periasamy, M (1999) SERCA1a can functionally substitute for SERCA2a in the heart. Am. J. Physiol. 276:H89-97

Abstract

We recently generated a transgenic (TG) mouse model in which the fast-twitch skeletal muscle sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA1a) is overexpressed in the heart. Ectopic overexpression of SERCA1a results in remodeling of the cardiac SR containing 80% SERCA1a and 20% endogenous SERCA2a with an approximately 2.5-fold increase in the total amount of SERCA protein (E. Loukianov et al. Circ. Res. 83: 889-897, 1998). We have analyzed the Ca2+ transport properties of membranes from SERCA1a TG hearts in comparison to control hearts. Our data show that the maximal velocity of SR Ca2+ transport was significantly increased ( approximately 1.9-fold) in TG hearts, whereas the apparent affinity of the SERCA pump for Ca2+ was not changed. Addition of phospholamban antibody in the Ca2+ uptake assays increased the apparent affinity for Ca2+ to the same extent in TG and non-TG (NTG) hearts, suggesting that phospholamban regulates the SERCA1a pump in TG hearts. Analysis of SERCA enzymatic properties in TG hearts revealed that the SERCA pump affinity for ATP, the Hill coefficient, the pH dependence of Ca2+ uptake, and the effect of acidic pH on Ca2+ transport were similar to those of NTG hearts. Interestingly, the rate constant of phosphoenzyme decay (turnover rate of SERCA enzyme) was also very similar between TG and NTG hearts. Together these findings suggest that 1) the SERCA1a pump can functionally substitute for SERCA2a and is regulated by endogenous phospholamban in the heart and 2) SERCA1a exhibits several enzymatic properties similar to those of SERCA2a when expressed in a cardiac setting.

Links

PubMed

Keywords

Adenosine Triphosphate/metabolism; Animals; Biological Transport/physiology; Calcium/metabolism; Calcium-Binding Proteins/physiology; Calcium-Transporting ATPases/metabolism; Hydrogen-Ion Concentration; Hydrolysis; Isoenzymes/metabolism; Mice; Mice, Transgenic; Myocardium/metabolism; Reference Values; Sarcoplasmic Reticulum/metabolism; Time Factors

Significance

Annotations

Gene product Qualifier GO ID GO term name Evidence Code with/from Aspect Notes Status


See also

References

See Help:References for how to manage references in GONUTS.