Biological cell membranes regulate the transfer of matter and informa­ tion between the intracellular and extracellular compartments as basic survival and maintenance functions for an organism: This volume contains a series of reviews that are concerned with how biological plasma membranes regulate the transport of chloride between the intracellular and extracellular compartments of a cell. This book is also an attempt to analyze the molecular basis for the movement of chloride across a cell membrane. This volume is devoted to a diversity of electrogenic chloride transport mechanisms in representative cell membranes of all living things. The first section of the book (Chaps. 1-4) focuses on mech­ anisms of primary active chloride transport (i.e. photon or A TP-driven), while the second section (Chaps. 5-6) centers on secondary active chloride transporters (symport and antiport) in both plant and animal plasma membranes. The last section, which comprises seven chapters (Chaps. 7-13), deals with chloride channels in cell membranes of prokaryocytes and eukaryocytes of most every phylum. It is hoped that with this particular ordering the reader can glean a telescopic view of the evolutionary history of the various electrogenic chloride transporters.

1 Halorhodopsin: A Prokaryotic Light-Driven Active Chloride Transport System.- 1 Introduction.- 2 Anion Binding and the Retinal Chromophore as Reporter Group.- 3 The Photocycle.- 4 Light-Dependent Retinal Isomerizations and Schiff Base Deprotonation.- 5 Hypotheses of the Transport Mechanism.- References.- 2 Chloride ATPase in Marine Algae.- 1 Introduction.- 2 Objects.- 3 Some Conditions.- 4 Basic Observations: The Pump and Its Transportée.- 5 Fueling Substrate.- 6 Electrical Properties.- 7 Biochemical Approaches.- 8 Conclusions and Speculations.- References.- 3 Existence of a Chloride Pump in Molluscs.- 1 Introduction.- 2 Electrical Characteristics of Aplysia Gut.- 3 Biochemistry of the Cl? Pump.- 4 Sulfhydryl Ligands of the Cl? Pump.- 5 Reconstitution of the Cl? Pump.- 6 Molecular Weight and Reaction Sequence of the Cl? Pump.- 7 Conclusions.- References.- 4 Transporting Cl?-ATPase in Rat Brain.- 1 Introduction.- 2 Cl?-Stimulated ATPase in Mammalian Brain.- 3 Functional Significance of Cl? Pump in the Brain.- 4 Conclusions.- References.- 5 Proton-Coupled Chloride Transport in Plant Cells.- 1 Introduction.- 2 Evidence for Gradient-Coupled Cl? Transport.- 3 Kinetic Properties of Gradient-Coupled Cl? Transport at the Plasma Membrane.- 4 Conclusions and Future Prospects.- References.- 6 Electrogenic Coupling of Sulfate Secretion to Chloride Transport in Lobster Hepatopancreas.- 1 Introduction.- 2 Vertebrate Sulfate Transport Mechanisms.- 3 Transmembrane SO4/C1 Exchange in Vertebrate Epithelia.- 4 Transmembrane Sulfate Antiport in Hepatopancreatic Epithelium.- 5 Transcellular Sulfate Transport in Lobster Hepatopancreas.- References.- 7 Chloride Currents in Lower Organisms.- 1 Introduction.- 2 Protists.- 3 Porifera.- 4 Cnidaria.- 5 Platyhelminths.- 6Nematodes.- 7 Discussion.- References.- 8 Chloride Channels in Molluscs.- 1. Introduction.- 2. Excitable Cell Cl? Channels.- 3. Aplysia Gut Absorptive Cells.- References.- 9 Chloride Channels in Insects: A Search for Common Grounds.- 1 Introduction.- 2 Defining Characteristics of Vertebrate Epithelial Cl? Channels.- 3 Cl? Channels in Insect Epithelial Secretion and Absorption.- 4 GABA-Activated Cl? Channel in Nervous System and Muscle.- 5 Conclusions.- References.- 10 The Voltage-Gated Cl? Channel of Torpedo Electroplax: an Emerging View of its Structure and Function.- 1 Introduction.- 2 Electrocyte Physiology.- 3 Biophysics of the Cl? Channel.- 4 Biochemical Studies.- 5 Molecular Genetics of the Cl? Channel.- 6 Conclusion.- References.- 11 A Secretory Cl Channel from Epithelial Cells Studied in Heterologous Expression Systems.- 1 Introduction.- 2 Channels Implicated in Transepithelial Chloride Secretion.- 3 CFTR Expression and Reconstitution Generate the Low-Conductance Cl Channel.- 4 Properties of the CFTR Pore.- 5 Regulation of the CFTR Channel by Phosphorylation.- 6 Regulation of CFTR Channel by Nucleotides.- 7 Homologs from Other Species: Shark CFTR is also a Cl Channel.- 8 Conclusions.- References.- 12 Chloride Channels in Epithelial Cells of Intestine.- 1 Introduction.- 2 Small Intestine.- 3 Colon.- 4 Summary.- References.- 13 Chloride Transport by Gastric Mucosa.- 1 Introduction.- 2 Acidic and Nonacidic Cl? Secretion.- 3 Identification and Localization of Ion Transport Pathways.- 4 Localization of Passive Ion Transporters.- References.