Rapid anisotropic motion of the Ca2+-transport ATPase of the rabbit skeletal muscle sarcoplasmic reticulum

1977 ◽  
Vol 55 (6) ◽  
pp. 587-596 ◽  
Author(s):  
Barbara A. Manuck ◽  
Brian D. Sykes
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Relaxation Times ◽  
Rotational Correlation Time ◽  
Rabbit Skeletal Muscle ◽  
Nuclear Spin Relaxation ◽  
Anisotropic Model ◽  
Transport Atpase ◽  
Anisotropic Motion ◽  
Membrane Bound

1H nuclear magnetic resonance techniques were used to study the binding of uridine 5′-triphosphate to the Ca2+-transport ATPase (EC 3.6.1.3) of sarcoplasmic reticulum vesicles from rabbit skeletal muscle. The nuclear spin relaxation times determined for the bound nucleotide are used to characterize the rotational motion of the ATPase to which the nucleotide is bound. The results, assuming an anisotropic model for the motion of the ATPase in the membrane, place a low upper limit on the rotational correlation time of the ATPase. This indicates that the motion of the ATPase in the membrane is quite rapid when compared, for example, with the motion found for other membrane-bound proteins such as rhodopsin.

scholarly journals Synthesis of adenosine triphosphate during release of intravesicular and membrane-bound calcium ions from passively loaded sarcoplasmic reticulum

1976 ◽  
Vol 156 (2) ◽  
pp. 239-244 ◽  
Author(s):  
M G P Vale ◽  
V R O E Osório ◽  
E Castro ◽  
A P Carvalho
Keyword(s):  
Skeletal Muscle ◽  
Acetic Acid ◽  
Sarcoplasmic Reticulum ◽  
Adenosine Triphosphate ◽  
Calcium Ions ◽  
Rabbit Skeletal Muscle ◽  
Membrane Bound

Sarcoplasmic reticulum isolated from rabbit skeletal muscle and incubated in a medium containing Ca2+ in the absence of ATP retains intravesicular and/or membrane-bound Ca2+. The synthesis of ATP coupled with the release of intravesicular Ca2+ is totally inhibited by the ionophore X-537A. Release of the membrane-bound Ca2+, retained after short periods of incubation (10min) or after release of the intravesicular Ca2+ by ionophore X-537A, still supports some synthesis of ATP. The ratios of Ca2+ released to ATP synthesized are 2.5-3.2, when bound and intravesicular Ca2+ are released simultaneously, and 3.1-4.0, when only bound Ca2+ is released. The results show that the synthesis of ATP by sarcoplasmic reticulum during release of passively accumulated Ca2+ by EGTA [ethanedioxybis(ethylamine)tetra-acetic acid] is accompanied by a loss of membrane-bound Ca2+.

scholarly journals Calsequestrin: a well-known but curious protein in skeletal muscle

2020 ◽  
Vol 52 (12) ◽  
pp. 1908-1925
Author(s):  
Jin Seok Woo ◽  
Seung Yeon Jeong ◽  
Ji Hee Park ◽  
Jun Hee Choi ◽  
Eun Hui Lee
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Human Skeletal Muscle ◽  
Rabbit Skeletal Muscle ◽  
Muscle Type ◽  
Muscle Diseases ◽  
The Past ◽  
Muscle Tissues ◽  
Suitable Amount ◽  
Terminal Cisternae

AbstractCalsequestrin (CASQ) was discovered in rabbit skeletal muscle tissues in 1971 and has been considered simply a passive Ca2+-buffering protein in the sarcoplasmic reticulum (SR) that provides Ca2+ ions for various Ca2+ signals. For the past three decades, physiologists, biochemists, and structural biologists have examined the roles of the skeletal muscle type of CASQ (CASQ1) in skeletal muscle and revealed that CASQ1 has various important functions as (1) a major Ca2+-buffering protein to maintain the SR with a suitable amount of Ca2+ at each moment, (2) a dynamic Ca2+ sensor in the SR that regulates Ca2+ release from the SR to the cytosol, (3) a structural regulator for the proper formation of terminal cisternae, (4) a reverse-directional regulator of extracellular Ca2+ entries, and (5) a cause of human skeletal muscle diseases. This review is focused on understanding these functions of CASQ1 in the physiological or pathophysiological status of skeletal muscle.

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