Ion Transport is a collection of papers from the Smith Kline & French Research "Symposium on Ion Transport" held in Cambridge, on April 12-14, 1989. These papers focus on the plasma membrane, particularly on the three main classes of transporters, namely, pumps, exchangers, and channels. Some papers discuss the different experimental approaches from electrophysiological and ion flux measurements through pharmacology, molecular biology, electrostatics, and computer modeling. Other papers discuss the P-type cation pump, a class of ATP-driven ion pumps, which is determined from its subunit composition and from the results of the hydrolysis of ATP. Several papers explain the techniques used in ion channels and their modulation. These techniques can be used in the voltage-gated Na+ channel or in permeation mechanisms. Other papers examine the transport proteins involved in the physiology of ion transport. Ions and fluid transport relate to, at the molecular level, how ions cross membranes. A minimum model, in conjunction with theoretical perspective, can describe the mechanism by which ions move through channels. This collection can prove beneficial for biochemists, micro-biologists, cellular researchers, and academicians involved in the study of cellular biology or biophysics.

ContributorsForewordIntroductionPart 1: P-Type Cation Pumps 1 Extracytosolic Functional Domains of the H+,K+-ATPase Complex 1 Introduction 2 Results 3 Discussion Acknowledgments References 2 The Mechanism of Cation Transport by the Na+,K+-ATPase 1 Introduction 2 The Transport Mechanism 3 Cation Occlusion 4 Cation Selectivity 5 Trans Effects of Na+ 6 Cation Slippage Fluxes 7 Electrogenic Potentials 8 Effects of Voltage on the Pump 9 The structure of the Cation-Binding Sites 10 Future directions Acknowledgments References 3 The Nucleotide-Binding Site of the Plasma-Membrane H+-ATPase of Neurospora Crassa: A Comparison with Other P-Type ATPases 1 Introduction 2 Nucleotide Binding 3 Sequence Comparisons 4 Structure of the Nucleotide-Binding Site Acknowledgments ReferencesPart 2: Ion Channels and their Modulation 4 Voltage-Gated Sodium Channels Since 1952 1 Introduction 2 Distribution 3 Molecular Structure 4 Gating 5 Selectivity Filter and Pore 6 Modulated Receptors 7 Conclusion Acknowledgments References 5 Single Potassium Channels in Drosophila Nerve and Muscle 1 Introduction 2 Advantages of Drosophila as a System for the Study of Ion Channels 3 Tissue Culture Systems 4 A1 Channels 5 A2 Channels 6 KD Channels 7 K1 Channels 8 KO Channels 9 KST Channel 10 Shaker Differential Splicing does not Explain the Diversity of Channel Types Acknowledgement References 6 Calcium Channels: Properties and Modulation 1 Introduction 2 Ca2+ Channel Selectivity 3 Ca2+ Channel Gating 4 Ca2+ Channel Modulation Acknowledgments References 7 Calcium Channels in Mammalian Sympathetic Neurons and PC12 Cells 1 Introduction 2 Results and Discussion Acknowledgments References 8 Voltage-Dependent Calcium Channels of Smooth Muscle Cells 1 Introduction 2 Inward Current 3 Conclusions Acknowledgments References 9 Modulation of Calcium and Other Channels by G Proteins: Implications for the Control of Synaptic Transmission 1 Introduction 2 Modulation of Ca2+ Channels by G Protein Activation 3 Evidence for G Proteins Coupling to K+ Channels 4 Role of G Protein-Coupled Ion Channels in the Modulation of Synaptic Transmission 5 Conclusion References 10 The Structure of the Skeletal Muscle Calcium Channel 1 Introduction 2 Structural Composition of the Purified Skeletal Muscle Ca2+ Channel 3 Phosphorylation of the Purified CaCB-Receptor 4 Structure of the a1- and ß-Subunits of the Skeletal Muscle Ca2+ Channel 5 Identification of L-Type Ca2+ Channel Proteins in Other Tissues 6 Reconstitution of an L-Type Ca2+ Channel from the Skeletal Muscle CaCB-Receptor 7 Conclusions Acknowledgments References 11 Structural Characteristics of Cation and Anion Channels Directly Operated by Agonists 1 Classes of Receptor-Operated Channels 2 Ligand-Operated ion Channels 3 Vertebrate Nicotinic Acetylcholine Receptors 4 Homo-Oligomeric forms of Nicotinic Receptors in Insects 5 GABAA and Glycine Receptors 6 The Ion Channel in the Structure 7 Conclusions References 12 Activation and Desensitization of Glutamate Receptors in Mammalian CNS 1 Introduction 2 Techniques Used for Rapid Perfusion to Limit Desensitization 3 Responses to fast Applications of Excitatory Amino Acids 4 Glycine Modulates Desensitization at NMDA Receptors 5 Dose-Response Analysis for Activation of NMDA and Quisqualate Receptors 6 Implications for Synaptic Transmission Acknowledgments References 13 Receptor-Mediated Calcium Entry 1 Introduction 2 Electrophysiological Approaches 3 Studies with Fluorescent Indicators of [Ca2+]i 4 Conclusion Acknowledgments ReferencesPart 3: Ions and Fluid Transport 14 Pathways for Cell Volume Regulation Via Potassium and Chloride Loss 1 Introduction: Transport Processes Involved in RVD 2 Coupled KCl Co-Transport in Hepatocytes 3 Anion Dependence and Kinetic Properties of KCl Co-Transport in Red Cells 4 Specific Inhibitors of KCl Co-Transport 5 Loss of KCl Co-Transport on "Young" Red Cell Maturation 6 Discussion Acknowledgments References 15 Epithelial Chloride Channels: Properties and Regulation 1 Introduction 2 Properties of Epithelial Cl- Channels 3 Regulation of epithelial Cl- Channels 4 Conclusion Acknowledgments References 16 Purification and Reconstitution of the Epithelial Chloride Channel 1 Introduction 2 Solubilization and Affinity Chromatography 3 Reconstitution 4 Discussion Acknowledgments ReferencesPart 4: Models of Ion Permeation Across Membranes 17 Models of Ion Permeation through Membranes 1 Introduction 2 Molecular and Brownian Dynamics 3 Interpretation of Experimental Data References 18 Topics Relating to the Modeling of Ion Channel Function 1 A Threshold Model of Na+ Channel Kinetics 2 A Kinetic Role for Ionizable Residues in Channel Proteins ReferencesAppendix: Abstracts of PostersIndexColor Plate