Two-dimensional structure of phospholipase induced crystals of Ca2+-ATPase from sarcoplasmic reticulum

1986 ◽  
Vol 6 (12) ◽  
pp. 1065-1070 ◽  
Author(s):  
M. Misra ◽  
S. K. Malhotra
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Phospholipase A2 ◽  
Membrane Vesicles ◽  
Rabbit Skeletal Muscle ◽  
Dimensional Structure ◽  
Two Dimensional

A two-dimensional projection map was computed of the Ca2+-ATPase molecules in sarcoplasmic reticulum, isolated from rabbit skeletal muscle. Crystalline arrays of Ca2+-ATPase molecules were formed by incubating the membrane vesicles with phospholipase A2 and dialysing against Tris/HCl buffer. Ca2+-ATPase molecules appear as quasi-triangular blobs in the projection map and seem to form dimers. The projection map seems to indicate an enzyme conformation somewhat similar to vanadate-induced crystals but different from lanthanide-induced crystals of Ca2*-ATPase.

scholarly journals Drastic reduction of calsequestrin-like proteins and impaired calcium binding in dystrophic mdx muscle

2002 ◽  
Vol 92 (2) ◽  
pp. 435-445 ◽  
Author(s):  
Kevin Culligan ◽  
Niamh Banville ◽  
Paul Dowling ◽  
Kay Ohlendieck
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Muscular Dystrophy ◽  
Calcium Binding ◽  
Functional Decline ◽  
Two Dimensional ◽  
Drastic Reduction ◽  
Dystrophic Muscle ◽  
One Dimensional ◽  
Blotting Technique

Although the reduction in dystrophin-associated glycoproteins is the primary pathophysiological consequence of the deficiency in dystrophin, little is known about the secondary abnormalities leading to x-linked muscular dystrophy. As abnormal Ca2+ handling may be involved in myonecrosis, we investigated the fate of key Ca2+ regulatory membrane proteins in dystrophic mdx skeletal muscle membranes. Whereas the expression of the ryanodine receptor, the dihydropyridine receptor, the Ca2+-ATPase, and calsequestrin was not affected, a drastic decline in calsequestrin-like proteins of 150–220 kDa was observed in dystrophic microsomes using one-dimensional immunoblotting, two-dimensional immunoblotting with isoelectric focusing, diagonal two-dimensional blotting technique, and immunoprecipitation. In analogy, overall Ca2+ binding was reduced in the sarcoplasmic reticulum of dystrophic muscle. The reduction in Ca2+ binding proteins might be directly involved in triggering impaired Ca2+ sequestration within the lumen of the sarcoplasmic reticulum. Thus disturbed sarcolemmal Ca2+ fluxes seem to influence overall Ca2+homeostasis, resulting in distinct changes in the expression profile of a subset of Ca2+ handling proteins, which might be an important factor in the progressive functional decline of dystrophic muscle fibers.

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.

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.

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