The Role of Lipids in the Functioning of a Membrane Protein: The Sarcoplasmic Reticulum Calcium Pump

Author(s):  
J.P. Bennett ◽  
K.A. McGill ◽  
G.B. Warren
2009 ◽  
Vol 96 (3) ◽  
pp. 326a
Author(s):  
Chevon Thorpe ◽  
Lesly De Arras ◽  
John P. Toscano ◽  
Gizem Keceli ◽  
Christopher Pavlos ◽  
...  

Author(s):  
Jussi T. Koivumäki ◽  
Jouni Takalo ◽  
Topi Korhonen ◽  
Pasi Tavi ◽  
Matti Weckström

When developing large-scale mathematical models of physiology, some reduction in complexity is necessarily required to maintain computational efficiency. A prime example of such an intricate cell is the cardiac myocyte. For the predictive power of the cardiomyocyte models, it is vital to accurately describe the calcium transport mechanisms, since they essentially link the electrical activation to contractility. The removal of calcium from the cytoplasm takes place mainly by the Na + /Ca 2+ exchanger, and the sarcoplasmic reticulum Ca 2+ ATPase (SERCA). In the present study, we review the properties of SERCA, its frequency-dependent and β -adrenergic regulation, and the approaches of mathematical modelling that have been used to investigate its function. Furthermore, we present novel theoretical considerations that might prove useful for the elucidation of the role of SERCA in cardiac function, achieving a reduction in model complexity, but at the same time retaining the central aspects of its function. Our results indicate that to faithfully predict the physiological properties of SERCA, we should take into account the calcium-buffering effect and reversible function of the pump. This ‘uncomplicated’ modelling approach could be useful to other similar transport mechanisms as well.


1985 ◽  
Vol 40 (7-8) ◽  
pp. 571-575 ◽  
Author(s):  
Wilhelm Hasselbach ◽  
Andrea Migala

Abstract The decline of the transport ratio of the sarcoplasmic calcium pump observed in a recent study (A. results from the retardation of calcium oxalate precipitation at low calcium/protein ratios. The prevailing high internal calcium level supports a rapid calcium backflux and a compensatory ATP hydrolysis during net calcium uptake which reduces the transport ratio. Yet, the determined calcium back­ flux does not fully account for the decline of the transport ratio. A supposed modulation of the stoichiometry of the pump by external calcium (0.1 μм) is at variance with results of previous studies showing a constant transport ratio of two in the same calcium concentration range.


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