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This volume contains manuscripts based upon talks presented at the International Symposium on Signal Transduction in Photoreceptor Cells which was held at the Forschungszentrum Jiilich August 8-11, 1990. The meeting was dedicated to the memory of Hermann Kuhn who made major contributions to our understand ing of transduction pathways in visual cells. Presentations at the meeting were organized around the following topics: (1) Rhodopsin Structure and Function, (2) Transducin and Phosphodiesterase, (3) Arrestin and Kinase, (4) The cGMP-gated 2 channel, (5) Role of Ca + in Photoreceptors, and (6) Transduction in Inverte brates. In a Plenary Lecture, D. Oesterhelt (Martinsried, FRG) described the sen sory transduction system of the halobacteria. These primitive organisms employ several retinal-containing pigments for sensory and ion-translocation purposes. Their study is intrinsically interesting as well as serving as potential models for the understanding of more complex systems. Study of the structure and function of rhodopsin has been greatly aided by use of the methods of molecular biology. T. Sakmar (Cambridge, MA, USA) described his use of site specific mutagenesis to make systematic substitutions of charged residues in the transmembrane helices of rhodopsin, leading to iden tification of the particular glutamic acid residue that serves as a counterion for the protonated Schiff base. Vertebrate rhodopsin has also been cloned and ex pressed in the baculovirus system, (W. DeGrip, Nijmegen, The Netherlands) which should facilitate production of sufficient quantities of mutant rhodopsin to allow biophysical studies.
List of contents
Hermann Kühn - In Memoriam.- Plenary Lecture.- The Eyes of Halobacteria.- I Rhodopsin - Structure and Function.- Mutagenesis Studies of Rhodopsin Phototransduction.- Structural Stability of Rhodopsin and Opsin Studied by Differential Scanning Calorimetry.- Molecular Analysis of Photoreceptor Protein Function.- Octopus Rhodopsin.- II Transducin and Phosphodiesterase.- The Activation of Transducin: Studies on its Mechanism and Modulation.- The Transitory Complexes Between Photoexcited Rhodopsin and Transducin. Biochemical and Spectroscopic Studies.- The Rate of GTP Hydrolysis by Transducin and the Termination of the cGMP Cascade in Retinal Rods.- The Molecular Biology of the Rod Photoreceptor cGMP Phosphodiesterase ?- and ?-Subunits.- III Deactivation Mechanisms.- The Phosphorylation of Rhodopsin.- Mechanisms of ?-Adrenergic Receptor Desensitization.- IV The cGMP-gated Channel.- Gating Kinetics of the cGMP-Activated Conductance of Retinal Cones.- Molecular Properties of the cGMP-gated Cation Channel of Rod Photoreceptor Cells as Probed with Monoclonal Antibodies.- Cyclic Nucleotide-gated Channels - A Family of Proteins Involved in Vertebrate Photoreception and Olfaction.- V Ca2+ Metabolism and Light Adaptation.- Interactions Between Calcium and cGMP in Dialyzed Detached Retinal Rod Outer Segments.- The Role of Cytoplasmic Calcium Concentration in Photoreceptor Light Adaptation.- Photoreceptor Guanylate Cyclase and Its Regulation by Calcium.- VI Transduction in Invertebrates.- Cyclic-GMP Phosphodiesterase in Photoreceptor Cells in Limulus Ventral Eye.- The Molecular Mechanism of Retinal Degeneration in the Retinal Degeneration B (rdgB) Mutant of Drosophila.- Glycosylation of Dipteran Opsins During Membrane Biogenesis.- Molecular Genetics of Visual Transduction inDrosophila.- Index of Contributors.
