Coupling of calcium transport to ATP hydrolysis by the calcium-ATPase of sarcoplasmic reticulum: potential role of the 53-kilodalton glycoprotein

Biochemistry ◽  
1985 ◽  
Vol 24 (18) ◽  
pp. 4876-4884 ◽  
Author(s):  
Kenneth S. Leonards ◽  
Howard Kutchai
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Calcium Transport ◽  
Potential Role ◽  
Atp Hydrolysis ◽  
Calcium Atpase

Calcium ATPase and intestinal calcium transport in uremic rats

1980 ◽  
Vol 238 (5) ◽  
pp. G424-G428
Author(s):  
H. Schiffl ◽  
U. Binswanger
Keyword(s):  
Enzyme Activity ◽  
Atpase Activity ◽  
Calcium Transport ◽  
Calcium Atpase ◽  
Intestinal Calcium Transport ◽  
Identical Response ◽  
Close Relationship ◽  
Intact Rats

Calcium ATPase, an enzyme involved in intestinal calcium transport, was measured in homogenates of duodenal mucosal scrapings of normal and uremic rats. The effects of calcium deprivation and treatment with 1 alpha,25-dihydroxycholecalciferol [1,25-(OH)2D3] were investigated as well. Uremia decreased the enzyme activity and impaired the rise after calcium deprivation as observed in intact rats. The 1,25-(OH)2D3 treatment increased the enzyme activity in uremic animals and resulted in an identical response to calcium deprivation as observed in intact rats; parathyroidectomy abolished this effect. A striking correlation between everted duodenal gut sac calcium transport and calcium ATPase activity could be demonstrated for all groups of rats studied. It is concluded that the calcium ATPase activity is linked to the production of 1,25-(OH)2D3 as well as to an additional factor, probably parathyroid hormone. The close relationship between enzyme activity and in vitro calcium transport, even during constant physiological supplementation with 1,25-(OH)2D3, suggests an autonomous role of the calcium ATPase activity for mediation of calcium transport in the duodenum in addition to the well-known mechanisms related to vitamin D and its metabolites.

scholarly journals Uncoupling of sarcoendoplasmic reticulum calcium ATPase pump activity by sarcolipin as the basis for muscle non-shivering thermogenesis

2020 ◽  
Vol 375 (1793) ◽  
pp. 20190135 ◽  
Author(s):  
Naresh C. Bal ◽  
Muthu Periasamy
Keyword(s):  
Energy Homeostasis ◽  
Atp Hydrolysis ◽  
Calcium Atpase ◽  
Whole Body ◽  
Signalling Molecule ◽  
Brown Adipose ◽  
Pump Activity ◽  
Body Energy ◽  
Shivering Thermogenesis

Thermogenesis in endotherms relies on both shivering and non-shivering thermogenesis (NST). The role of brown adipose tissue (BAT) in NST is well recognized, but the role of muscle-based NST has been contested. However, recent studies have provided substantial evidence for the importance of muscle-based NST in mammals. This review focuses primarily on the role of sarcoplasmic reticulum (SR) Ca 2+ -cycling in muscle NST; specifically, it will discuss recent data showing how uncoupling of sarcoendoplasmic reticulum calcium ATPase (SERCA) (inhibition of Ca 2+ transport but not ATP hydrolysis) by sarcolipin (SLN) results in futile SERCA pump activity, increased ATP hydrolysis and heat production contributing to muscle NST. It will also critically examine how activation of muscle NST can be an important factor in regulating metabolic rate and whole-body energy homeostasis. In this regard, SLN has emerged as a powerful signalling molecule to promote mitochondrial biogenesis and oxidative metabolism in muscle. Furthermore, we will discuss the functional interplay between BAT and muscle, especially with respect to how reduced BAT function in mammals could be compensated by muscle-based NST. Based on the existing data, we argue that SLN-mediated thermogenesis is an integral part of muscle NST and that muscle NST potentially contributed to the evolution of endothermy within the vertebrate clade. This article is part of the theme issue ‘Vertebrate palaeophysiology’.

Role of the Sarcoplasmic Reticulum Ca2+-ATPase on Heat Production and Thermogenesis

2001 ◽  
Vol 21 (2) ◽  
pp. 113-137 ◽  
Author(s):  
Leopoldo de Meis
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Atp Hydrolysis ◽  
Surrounding Medium ◽  
Chemical Energy ◽  
The Past ◽  
Sarcoplasmic Reticulum Membrane ◽  
Membrane Bound ◽  
Hydrolysis Of ◽  
Heat Released

The sarcoplasmic reticulum of skeletal muscle retains a membrane bound Ca2+-ATPase which is able to interconvert different forms of energy. A part of the chemical energy released during ATP hydrolysis is converted into heat and in the bibliography it is assumed that the amount of heat produced during the hydrolysis of an ATP molecule is always the same, as if the energy released during ATP cleavage were divided in two non-interchangeable parts: one would be converted into heat, and the other used for Ca2+ transport. Data obtained in our laboratory during the past three years indicate that the amount of heat released during the hydrolysis of ATP may vary between 7 and 32 kcal/mol depending on whether or not a transmembrane Ca2+ gradient is formed across the sarcoplasmic reticulum membrane. Drugs such as heparin and dimethyl sulfoxide are able to modify the fraction of the chemical energy released during ATP hydrolysis which is used for Ca2+ transport and the fraction which is dissipated in the surrounding medium as heat.

The mechanism of coupling chemical and physical reactions by the calcium ATPase of sarcoplasmic reticulum and other coupled vectorial systems

1995 ◽  
Vol 15 (5) ◽  
pp. 283-287 ◽  
Author(s):  
William P. Jencks
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Chemical Reaction ◽  
Atp Hydrolysis ◽  
Calcium Atpase

The coupling of the chemical reaction of ATP hydrolysis to the transport of calcium from the cytoplasm into the lumen of sarcoplasmic reticulum vesicles can be defined by a set of rules that define alternating changes in the specificities of the enzyme for catalysis of chemical and physical reactions.

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