Mechanism of Ca²⁺Transport by Sarcoplasmic Reticulum

Abstract

The sections in this article are: Structure of Sarcoplasmic Reticulum and Transverse Tubules Structure of Plasmalemma and T Tubules Sarcoplasmic Reticulum Junction Between T Tubules and SR Mechanism of Excitation‐Contraction Coupling Isolation of SR , T Tubules, and Surface Membrane Elements from Skeletal Muscle Separation of Membrane Fractions by Calcium Oxalate or Calcium Phosphate Loading Protein Composition of SR Structure of Ca 2+ ‐Transport ATP ase and Its Disposition in SR Membrane Fragmentation of Ca 2+ ‐ ATP ase With Proteolytic Enzymes Primary Sequence of Ca 2+ ‐Transport ATP ase From Rabbit SR Structure of Proteolipids Structure and Distribution of Calsequestrin and High‐Affinity Ca 2+ ‐Binding Protein in SR Lipid Composition of SR Distribution of Phospholipids in Membrane Bilayer Role of Phospholipids in Atpase Activity and CA 2+ Transport Boundary Lipids and the Problem of Lipid Annulus Rate of ATP Hydrolysis and Physical Properties of the Lipid Phase Mobility of Phospholipids and Ca 2+ ‐Transport ATP ase in SR Mechanism of ATP Hydrolysis and CA 2+ Transport Introduction of Reaction Sequence Ca 2+ Binding to SR Binding of Ca 2+ to Ca 2+ ‐Transport ATP ase Binding of Mg 2+ to Ca 2+ ‐ ATPase Binding of ATP to Ca 2+ ‐ ATPase Binding of Various Substrates to Ca 2+ ‐ ATPase Influence of ATP on Mobility and Reactivity of Protein Side‐Chain Groups Formation of Enzyme‐Substrate Complex Formation and Properties of Phosphoproteins Kinetics of E∼P Formation Relationship Between Enzyme Phosphorylation and Translocation of Calcium Changes in Ca 2+ Affinity of Phosphoenzyme During Ca 2+ Translocation ADP ‐Sensitive and ADP ‐insensitive Phosphoprotein Intermediates Effect of Potassium on ATPase Activity and Ca 2+ Transport Reversal of the CA 2+ Pump Ca 2+ Release Induced by ADP + P i Ca 2+ Gradient‐Dependent Phosphorylation of ATPase by P i Arsenate‐Induced Ca 2+ Release Mechanism of Ca 2+ Release Induced by ADP + P i Ca 2+ Gradient‐Independent Phosphorylation of Ca 2+ ‐ ATPase by P i Role of Ca 2+ ‐Protein Interactions in ATP Synthesis P i HOH Exchange NTP P i Exchange Physical Basis of CA 2+ Translocation Protein‐Protein Interactions in SR and Their Functional Significance Electron Microscopy Fluorescence‐Energy Transfer Electron Spin Resonance Studies ATP ase‐ ATP ase Interactions in Detergent Solutions Chemical Cross‐Linking Effects of Inhibitors on ATPase Activity Possibility of Subunit Heterogeneity Conclusion Permeability of SR Monovalent‐Cation Channels in SR Anion Channels in SR Effect of Membrane Proteins on Permeability of SR Membranes Relationship Between Membrane Potential and Calcium Fluxes Across SR Membrane Probes as Indicators of SR Membrane Potential Influence of SR Membrane Potential on Calcium Permeability Influence of Membrane Potential on Active Calcium Transport Effect of Calcium Uptake on Membrane Potential of SR A Critical Analysis of Experimental Findings on Effects of Ca 2+ Transport on Membrane Potential Effect of Calcium on Optical Response of Positive Cyanine Dyes Response of Negatively Charged Dyes to Calcium Transport by SR Vesicles Membrane Potential of SR In Vivo Effect of Ca 2+ Release on Membrane Potential of SR Transport of CA 2+ by Cardiac SR Kinetic Differences Between SR of Fast‐Twitch and Slow‐Twitch Skeletal Muscles Regulation of CA 2+ Transport by Membrane Phosphorylation Role of Protein Kinase‐Dependent Membrane Phosphorylation in Regulation of Ca 2+ Transport by Skeletal Muscle SR Physiological Significance of Phospholamban Phosphorylation Biosynthesis of SR Studies on SR Development In Vivo Assembly of SR in Cultured Skeletal and Cardiac Muscle Synthesis of Ca 2+ ‐Transport ATPase in Cell‐Free Systems and Its Insertion into the Membrane Synthesis of Calsequestrin Regulation of Synthesis of Ca 2+ ‐Transport ATPase Myogenic Regulation Neural Influence on Concentration of Ca 2+ ‐ ATPase in Muscle Cells

Conformational states of sarcoplasmic reticulum Ca2+-ATPase as studied by proteolytic cleavage

“…It is also seen that the extrinsic protein, calsequestrin (a usual component of sarcoplasmic reticulum vesicles) is degraded by trypsin in the absence of Ca 2+ and vanadate, but not in the presence of either one of these ions. This indicates that the membrane is destabilized by digestion in absence of CaZ+-ATPase ligands since calsequestrin is located at the interior surface of the sarcoplasmic reticulum vesicle [30,40]. In accordance with this interpretation we found that ATPdriven net uptake of Ca 2+ into the vesicles disappears after tryptic digestion in absence of Ca 2+, whereas CaZ+-ATPase activity is stimulated (Table 1).…”

Digestion of proteins associated with the Z-disc by calpain

“…The absence of detectable cardiolipin and cholesterol shows that there was little mitochondrial lipid. Skeletal muscle sarcoplasmic reticulum (Martonosi & Beeler, 1983) has higher propor- …”

Phenotypic adaptations in human muscle fibers 6 and 24 wk after spinal cord injury

“…Regulatory proteins include phospholamban, which is thought to impart slow kinetic properties to the SERCA2 pump in slow fibers (23,28), and sarcolipin, a protein found in fast fibers that appears to confer fast pump kinetics to the SERCA1 isoform (34). In addition, fast fibers contain higher total amounts of SR (as measured by SR membrane volume percentage) and total SERCA protein (13,32). Thus different fiber types have both qualitative and quantitative differences in SR properties, each of which may contribute to the greater fatigability of fast fibers (15,16,53).…”