scholarly journals Evidence for the presence in smooth muscle of two types of Ca2+-transport ATPase

1984 ◽  
Vol 224 (2) ◽  
pp. 445-451 ◽  
Author(s):  
F Wuytack ◽  
L Raeymaekers ◽  
J Verbist ◽  
H De Smedt ◽  
R Casteels
Keyword(s):  
Skeletal Muscle ◽  
Endoplasmic Reticulum ◽  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Acid Medium ◽  
Erythrocyte Membrane ◽  
Proteolytic Degradation ◽  
Transport Atpase ◽  
Degradation Pattern ◽  
Transport Atpases

Membrane fractions prepared from smooth muscle of the pig stomach (antral part) contain two Ca2+-dependent phosphoprotein intermediates belonging to different Ca2+-transport ATPases. These alkali-labile phosphoproteins can be separated by electrophoresis in acid medium. The 130 kDa phosphoprotein resembles a corresponding protein in the erythrocyte membrane, whereas the 100 kDa protein resembles that of the Ca2+-transport ATPase in sarcoplasmic reticulum from skeletal muscle. These resemblances are expressed in terms of Mr, reaction to La3+ and in a similar proteolytic degradation pattern. The presence of the calmodulin-stimulated ATPase in mixed membranes from smooth muscle is confirmed by its binding of calmodulin and antibodies against erythrocyte Ca2+-transport ATPase, whereas such binding does not occur with proteins present in the presumed endoplasmic reticulum from smooth muscle.

scholarly journals Smooth muscle expresses a cardiac/slow muscle isoform of the Ca2+-transport ATPase in its endoplasmic reticulum

1989 ◽  
Vol 257 (1) ◽  
pp. 117-123 ◽  
Author(s):  
F Wuytack ◽  
Y Kanmura ◽  
J A Eggermont ◽  
L Raeymaekers ◽  
J Verbist ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Endoplasmic Reticulum ◽  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Cardiac Muscle ◽  
Muscle Enzymes ◽  
Transport Atpase ◽  
Slow Twitch ◽  
Transport Atpases ◽  
Fast Twitch

Smooth muscle expresses in its endoplasmic reticulum an isoform of the Ca2+-transport ATPase that is very similar to or identical with that of the cardiac-muscle/slow-twitch skeletal-muscle form. However, this enzyme differs from that found in fast-twitch skeletal muscle. This conclusion is based on two independent sets of observations, namely immunological observations and phosphorylation experiments. Immunoblot experiments show that two different antibody preparations against the Ca2+-transport ATPase of cardiac-muscle sarcoplasmic reticulum also recognize the endoplasmic-reticulum/sarcoplasmic-reticulum enzyme of the smooth muscle and the slow-twitch skeletal muscle whereas they bind very weakly or not at all to the sarcoplasmic-reticulum Ca2+-transport ATPase of the fast-twitch skeletal muscle. Conversely antibodies directed against the fast-twitch skeletal-muscle isoform of the sarcoplasmic-reticulum Ca2+-transport ATPase do not bind to the cardiac-muscle, smooth-muscle or slow-twitch skeletal-muscle enzymes. The phosphorylated tryptic fragments A and A1 of the sarcoplasmic-reticulum Ca2+-transport ATPases have the same apparent Mr values in cardiac muscle, slow-twitch skeletal muscle and smooth muscle, whereas the corresponding fragments in fast-twitch skeletal muscle have lower apparent Mr values. This analytical procedure is a new and easy technique for discrimination between the isoforms of endoplasmic-reticulum/sarcoplasmic-reticulum Ca2+-transport ATPases.

scholarly journals Ethanol has different effects on Ca2+-transport ATPases of muscle, brain and blood platelets

1995 ◽  
Vol 312 (3) ◽  
pp. 733-737 ◽  
Author(s):  
F Mitidieri ◽  
L de Meis
Keyword(s):  
Skeletal Muscle ◽  
Endoplasmic Reticulum ◽  
Sarcoplasmic Reticulum ◽  
Atpase Activity ◽  
Blood Platelets ◽  
Activity Increase ◽  
Low Concentrations ◽  
Biphasic Effect ◽  
Transport Atpases

The effects of ethanol on different sarco/endoplasmic reticulum Ca(2+)-transport ATPases (SERCAs) were studied. In sarcoplasmic reticulum vesicles, ethanol concentrations varying from 5 to 20% promoted a progressive inhibition of Ca2+ uptake, enhancement of Ca2+ efflux, activation of the ATPase activity, increase of the enzyme phosphorylation by ATP and inhibition of enzyme phosphorylation by P1. The effects of ethanol on Ca2+ uptake and Ca2+ efflux were antagonized by Mg2+, P(i) and spermine. The increased efflux promoted by ethanol was antagonized by Ca2+ and thapsigargin. In brain and platelet vesicles a biphasic effect of ethanol was observed, so that activation occurred at low concentrations (5-10%) and inhibition at higher concentrations. The activation was not observed with the use of n-propanol and n-butanol. Different from the situation in sarcoplasmic reticulum, the decrease of the Ca2+ uptake in brain and platelet vesicles was associated with an inhibition of the ATPase activity. Mg2+ and P(i) antagonized the enhancement of Ca2+ efflux and the inhibition of Ca2+ uptake promoted by ethanol. However, thapsigargin and Ca2+ did not arrest the Ca2+ efflux promoted by ethanol in brain and platelet preparations. These results suggest that, in sarcoplasmic reticulum vesicles, ethanol uncouples the pump, promoting its activity as a Ca2+ channel. The SERCA isoform found in skeletal muscle has different properties from the isoforms found in brain and blood platelets.

scholarly journals Reversal of the Ca2+ pump of blood platelets

1995 ◽  
Vol 306 (1) ◽  
pp. 35-38 ◽  
Author(s):  
J C Benech ◽  
H Wolosker ◽  
L de Meis
Keyword(s):  
Skeletal Muscle ◽  
Endoplasmic Reticulum ◽  
Amino Acid ◽  
Sarcoplasmic Reticulum ◽  
Blood Platelets ◽  
Specific Inhibitor ◽  
Amino Acid Sequences ◽  
Transport Systems ◽  
Muscle Enzyme ◽  
Transport Atpase

In this study, the endoplasmic Ca2+ transport ATPase of blood platelets was compared with the Ca2+ ATPase of sarcoplasmic reticulum skeletal muscle. Similar to the muscle enzyme, the Ca2+ ATPase from platelets was found to catalyse an ATP<-->P(i) exchange both in the presence and in the absence of a transmembrane Ca2+ gradient. When platelet vesicles are loaded with Ca2+ and diluted in medium containing ADP, P(i) and EGTA, the ATPase catalyses Ca2+ efflux coupled to synthesis of ATP. The stoichiometry between Ca2+ ion released and ATP synthesized by platelet Ca2+ ATPase is 1, while that of skeletal muscle is 2. Thapsigargin, a specific inhibitor of sarcoplasmic/endoplasmic reticulum Ca2+ ATPases, inhibited both the Ca(2+)-dependent ATPase activity and the reversal of the platelet Ca2+ pump. The possibility is discussed that the differences observed between the two transport systems is related to the distinct amino acid sequences of the enzymes.

Electron Probe Analysis of Muscle

1982 ◽  
Vol 40 ◽  
pp. 398-401
Author(s):  
A. V. Somlyo ◽  
H. Shuman ◽  
A. P. Somlyo
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Resting State ◽  
Binding Sites ◽  
Electron Probe ◽  
Frog Skeletal Muscle ◽  
Electron Probe Analysis ◽  
Probe Analysis

Electron probe analysis of frozen dried cryosections of frog skeletal muscle, rabbit vascular smooth muscle and of isolated, hyperpermeab1 e rabbit cardiac myocytes has been used to determine the composition of the cytoplasm and organelles in the resting state as well as during contraction. The concentration of elements within the organelles reflects the permeabilities of the organelle membranes to the cytoplasmic ions as well as binding sites. The measurements of [Ca] in the sarcoplasmic reticulum (SR) and mitochondria at rest and during contraction, have direct bearing on their role as release and/or storage sites for Ca in situ.

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 Vesicle budding from endoplasmic reticulum is involved in calsequestrin routing to sarcoplasmic reticulum of skeletal muscles

2004 ◽  
Vol 379 (2) ◽  
pp. 505-512 ◽  
Author(s):  
Alessandra NORI ◽  
Elena BORTOLOSO ◽  
Federica FRASSON ◽  
Giorgia VALLE ◽  
Pompeo VOLPE
Keyword(s):  
Skeletal Muscle ◽  
Endoplasmic Reticulum ◽  
Sarcoplasmic Reticulum ◽  
Golgi Complex ◽  
Skeletal Muscles ◽  
Muscle Fibres ◽  
Vesicle Budding ◽  
Er Exit Sites ◽  
Skeletal Muscle Fibres ◽  
Mutant Forms

CS (calsequestrin) is an acidic glycoprotein of the SR (sarcoplasmic reticulum) lumen and plays a crucial role in the storage of Ca2+ and in excitation–contraction coupling of skeletal muscles. CS is synthesized in the ER (endoplasmic reticulum) and is targeted to the TC (terminal cisternae) of SR via mechanisms still largely unknown, but probably involving vesicle transport through the Golgi complex. In the present study, two mutant forms of Sar1 and ARF1 (ADP-ribosylation factor 1) were used to disrupt cargo exit from ER-exit sites and intra-Golgi trafficking in skeletal-muscle fibres respectively. Co-expression of Sar1-H79G (His79→Gly) and recombinant, epitope-tagged CS, CSHA1 (where HA1 stands for nine-amino-acid epitope of the viral haemagglutinin 1), barred segregation of CSHA1 to TC. On the other hand, expression of ARF1-N126I altered the subcellular localization of GM130, a cis-medial Golgi protein in skeletal-muscle fibres and myotubes, without interfering with CSHA1 targeting to either TC or developing SR. Thus active budding from ER-exit sites appears to be involved in CS targeting and routing, but these processes are insensitive to modification of intracellular vesicle trafficking and Golgi complex disruption caused by the mutant ARF1-N126I. It also appears that CS routing from ER to SR does not involve classical secretory pathways through ER–Golgi intermediate compartments, cis-medial Golgi and trans-Golgi network.

scholarly journals AIF4-induced inhibition of the ATPase activity, the Ca2+-transport activity and the phosphoprotein-intermediate formation of plasma-membrane and endo(sarco)plasmic-reticulum Ca2+-transport ATPases in different tissues. Evidence for a tissue-dependent functional difference

1989 ◽  
Vol 261 (2) ◽  
pp. 655-660 ◽  
Author(s):  
L Missiaen ◽  
F Wuytack ◽  
H De Smedt ◽  
F Amant ◽  
R Casteels
Keyword(s):  
Smooth Muscle ◽  
Plasma Membrane ◽  
Sarcoplasmic Reticulum ◽  
Atpase Activity ◽  
Intermediate Formation ◽  
Functional Difference ◽  
Transport Activity ◽  
Fast Skeletal Muscle ◽  
Transport Atpase ◽  
Plasmic Reticulum

AIF4- inhibits the (Ca2+ + Mg2+)-ATPase activity of the plasma-membrane and the sarcoplasmic-reticulum Ca2+-transport ATPase [Missiaen, Wuytack, De Smedt, Vrolix & Casteels (1988) Biochem. J. 253, 827-833]. The aim of the present work was to investigate this inhibition further. We now report that AIF4- inhibits not only the (Ca2+ + Mg2+)-ATPase activity, but also the ATP-dependent 45Ca2+ transport, and the formation of the phosphoprotein intermediate by these pumps. Mg2+ potentiated the effect of AIF4-, whereas K+ had no such effect. The plasma-membrane Ca2+-transport ATPase from erythrocytes was 20 times less sensitive to inhibition by AIF4- as compared with the Ca2+-transport ATPase from smooth muscle. The endoplasmic-reticulum Ca2+-transport ATPase from smooth muscle was inhibited to a greater extent than the sarcoplasmic-reticulum Ca2+-transport ATPase of slow and fast skeletal muscle.

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