ROLE OF THE SARCOPLASMIC RETICULUM IN GLYCOGEN METABOLISM

Sarcoplasmic vesicles and ß-glycogen particles 30–40 mµ in diameter were isolated from perfused rabbit skeletal muscle by the differential precipitation-centrifugation method. This microsomal fraction was subjected to zonal centrifugation on buffered sucrose gradients, in a B XIV Anderson type rotor, for 15 hr at 45,000 rpm in order to separate the two cytoplasmic organelles. Zonal profiles of absorbance at 280 mµ, proteins, glycogen, and enzymatic activities (phosphorylase b kinase, phosphorylase b, and glycogen synthetase) were performed. Whereas the entire synthetase activity was found combined with the glycogen particles, 39% of phosphorylase and 53% of phosphorylase b kinase activities, present in the microsomal fraction, were recovered in the purified vesicular fraction (d = 1.175). This latter fraction consists of vesicles, derived from the sarcoplasmic reticulum, and of small particles 10–20 mµ in diameter attached to the outer surface of the membranes. These particles disappear after α-amylase treatment. Incubation of the sarcovesicular fraction with 14C-labeled glucose-1-phosphate confirms the localization of a polysaccharide synthesis at the level of the membranes. "Flash activation" of phosphorylase b, i.e. Ca "activation" of phosphorylase kinase followed by a conversion of phosphorylase b into a, was demonstrated in the purified sarcovesicular fraction. Moreover, the active enzymatic sites were detected on the membranes by electron microscopy. The presence of binding sites between the membranes of the sarcoplasmic vesicles and a glycogen-enzyme complex suggests that this association plays a role in the glycogenolysis during muscle contraction.

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Ischemic Tolerance in Pre-Myelinated White Matter: The Role of Astrocyte Glycogen in Brain Pathology

Journal of Cerebral Blood Flow & Metabolism ◽

10.1038/jcbfm.2015.3 ◽

2015 ◽

Vol 35 (6) ◽

pp. 951-958 ◽

Cited By ~ 7

Author(s):

Robert Fern

Keyword(s):

White Matter ◽

Neural Development ◽

Energy Supply ◽

Necessary Conditions ◽

Volume Fraction ◽

Glycogen Metabolism ◽

Ischemic Tolerance ◽

Mitochondrial Volume ◽

Glycogen Particles

In isolated white matter, ischemic tolerance changes dramatically in the period immediately before the onset of myelination. In the absence of an extrinsic energy source, postnatal day 0 to 2 (P0 to P2) white matter axons are here shown to maintain excitability for over twice as long as axons > P2, a differential that was dependent on glycogen metabolism. Prolonged withdrawal of extrinsic energy supply tended to spare axons in zones around astrocytes, which are shown to be the sole repository for glycogen particles in developing white matter. Analysis of mitochondrial volume fraction revealed that neither axons nor astrocytes had a low metabolic rate in neonatal white matter, while oligodendroglia at older ages had an elevated metabolism. The astrocyte population is established early in neural development, and exhibits reduced cell density as maturation progresses and white matter expands. The findings show that this event establishes the necessary conditions for ischemia sensitivity in white matter and indicates that astrocyte proximity may be significant for the survival of neuronal elements in conditions associated with compromised energy supply.

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Calcium-Binding Properties of Sarcoplasmic Reticulum As Influenced by ATP, Caffeine, Quinine, and Local Anesthetics

The Journal of General Physiology ◽

10.1085/jgp.52.4.622 ◽

1968 ◽

Vol 52 (4) ◽

pp. 622-642 ◽

Cited By ~ 77

Author(s):

Arselio P. Carvalho

Keyword(s):

Skeletal Muscle ◽

Sarcoplasmic Reticulum ◽

Binding Sites ◽

Local Anesthetics ◽

Calcium Binding ◽

Rabbit Skeletal Muscle ◽

Cellular Membranes ◽

Binding Properties ◽

45Ca Fluxes

Calcium retained at binding sites of the sarcoplasmic reticulum membranes isolated from rabbit skeletal muscle requires 10-5 - 10-4 M ATP to exchange with 45Ca added to the medium. The ATP requirement for Ca exchangeability was observed with respect to the "intrinsic" Ca of the reticulum membranes and the fraction of Ca that is "actively" bound in the presence of ATP. Furthermore, a concentration of free Ca in the medium higher than 10-8 M is required for ATP to promote Ca exchangeability. This exchangeability is not influenced by caffeine, quinine, procaine, and tetracaine, and Ca that is either nonexchangeable (in the absence of ATP) or exchangeable (in the presence of ATP) is released by 1–5 mM quinine or tetracaine, but neither caffeine (6 mM) nor procaine (2–5 mM) has this effect. Quinine or tetracaine also releases Ca and Mg bound passively to the reticulum membranes. A possible role of ATP in maintaining the integrity of cellular membranes is discussed, and the effects of caffeine, quinine, and of local anesthetics on the binding of Ca by the isolated reticulum are related to the effects of these agents on 45Ca fluxes and on the twitch output observed in whole muscles.

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Role of Glycogen Phosphorylase Kinase in Regulation of Ca2+-ATPase of Sarcoplasmic Reticulum of the Common Frog Rana temporaria

Journal of Evolutionary Biochemistry and Physiology ◽

10.1023/b:joey.0000031012.31412.bb ◽

2004 ◽

Vol 40 (1) ◽

pp. 98-101 ◽

Cited By ~ 1

Author(s):

V. K. Shmelev ◽

T. P. Serebrenikova ◽

V. P. Nesterov

Keyword(s):

Sarcoplasmic Reticulum ◽

Glycogen Phosphorylase ◽

Rana Temporaria ◽

Phosphorylase Kinase ◽

Common Frog ◽

Frog Rana Temporaria ◽

The Common

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Calcium-Binding Properties of Sarcoplasmic Reticulum As Influenced by ATP, Caffeine, Quinine, and Local Anesthetics

The Journal of General Physiology ◽

10.1085/jgp.52.3.622 ◽

1968 ◽

Vol 52 (3) ◽

pp. 622-642 ◽

Cited By ~ 6

Author(s):

Arselio P. Carvalho

Keyword(s):

Skeletal Muscle ◽

Sarcoplasmic Reticulum ◽

Binding Sites ◽

Local Anesthetics ◽

Calcium Binding ◽

Rabbit Skeletal Muscle ◽

Cellular Membranes ◽

Binding Properties ◽

45Ca Fluxes

Calcium retained at binding sites of the sarcoplasmic reticulum membranes isolated from rabbit skeletal muscle requires 10-5 – 10-4 M ATP to exchange with 45Ca added to the medium. The ATP requirement for Ca exchangeability was observed with respect to the "intrinsic" Ca of the reticulum membranes and the fraction of Ca that is "actively" bound in the presence of ATP. Furthermore, a concentration of free Ca in the medium higher than 10-8 M is required for ATP to promote Ca exchangeability. This exchangeability is not influenced by caffeine, quinine, procaine, and tetracaine, and Ca that is either nonexchangeable (in the absence of ATP) or exchangeable (in the presence of ATP) is released by 1–5 mM quinine or tetracaine, but neither caffeine (6 mM) nor procaine (2–5 mM) has this effect. Quinine or tetracaine also releases Ca and Mg bound passively to the reticulum membranes. A possible role of ATP in maintaining the integrity of cellular membranes is discussed, and the effects of caffeine, quinine, and of local anesthetics on the binding of Ca by the isolated reticulum are related to the effects of these agents on 45Ca fluxes and on the twitch output observed in whole muscles.

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Electron Probe Analysis of Muscle

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100054583 ◽

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.

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Studies on progestin binding sites in the hepatic microsomal fraction of male and female rats

Acta Endocrinologica ◽

10.1530/acta.0.117s191 ◽

1988 ◽

Vol 117 (4_Suppl) ◽

pp. S191-S192

Author(s):

M. STOPPOK ◽

H. SCHRIEFERS ◽

E. R. LAX

Keyword(s):

Binding Sites ◽

Microsomal Fraction ◽

Female Rats ◽

Male And Female ◽

Male And Female Rats

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Faculty Opinions recommendation of Role of calsequestrin evaluated from changes in free and total calcium concentrations in the sarcoplasmic reticulum of frog cut skeletal muscle fibres.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1069694.522604 ◽

2007 ◽

Author(s):

Graham Lamb

Keyword(s):

Skeletal Muscle ◽

Sarcoplasmic Reticulum ◽

Muscle Fibres ◽

Total Calcium ◽

Skeletal Muscle Fibres

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Differentiation of nucleotide binding sites and role of metal ion in the adenylate kinase reaction by 31P NMR. Equilibria, interconversion rates, and NMR parameters of bound substrates

Journal of Biological Chemistry ◽

10.1016/s0021-9258(17)38123-1 ◽

1978 ◽

Vol 253 (4) ◽

pp. 1149-1158 ◽

Cited By ~ 3

Author(s):

B.D. Nageswara Rao ◽

M. Cohn ◽

L. Noda

Keyword(s):

Binding Sites ◽

Adenylate Kinase ◽

Metal Ion ◽

31P Nmr ◽

Nucleotide Binding ◽

Nucleotide Binding Sites ◽

Nmr Parameters ◽

Kinase Reaction

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The MarR-Type Regulator PA3458 Is Involved in Osmoadaptation Control in Pseudomonas aeruginosa

International Journal of Molecular Sciences ◽

10.3390/ijms22083982 ◽

2021 ◽

Vol 22 (8) ◽

pp. 3982

Author(s):

Karolina Kotecka ◽

Adam Kawalek ◽

Kamil Kobylecki ◽

Aneta Agnieszka Bartosik

Keyword(s):

Pseudomonas Aeruginosa ◽

Binding Sites ◽

Transcriptional Profiling ◽

Mrna Level ◽

Transcriptional Regulators ◽

Resistance Mechanisms ◽

Chronic Infections ◽

Environmental Signals ◽

Regulatory Systems

Pseudomonas aeruginosa is a facultative human pathogen, causing acute and chronic infections that are especially dangerous for immunocompromised patients. The eradication of P. aeruginosa is difficult due to its intrinsic antibiotic resistance mechanisms, high adaptability, and genetic plasticity. The bacterium possesses multilevel regulatory systems engaging a huge repertoire of transcriptional regulators (TRs). Among these, the MarR family encompasses a number of proteins, mainly acting as repressors, which are involved in response to various environmental signals. In this work, we aimed to decipher the role of PA3458, a putative MarR-type TR from P. aeruginosa. Transcriptional profiling of P. aeruginosa PAO1161 overexpressing PA3458 showed changes in the mRNA level of 133 genes; among them, 100 were down-regulated, suggesting the repressor function of PA3458. Concomitantly, ChIP-seq analysis identified more than 300 PA3458 binding sites in P. aeruginosa. The PA3458 regulon encompasses genes involved in stress response, including the PA3459–PA3461 operon, which is divergent to PA3458. This operon encodes an asparagine synthase, a GNAT-family acetyltransferase, and a glutamyl aminopeptidase engaged in the production of N-acetylglutaminylglutamine amide (NAGGN), which is a potent bacterial osmoprotectant. We showed that PA3458-mediated control of PA3459–PA3461 expression is required for the adaptation of P. aeruginosa growth in high osmolarity. Overall, our data indicate that PA3458 plays a role in osmoadaptation control in P. aeruginosa.

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