Current Topics in Cellular Regulation

Current Topics in Cellular Regulation: Volume 31 is a collection of papers that deals with the role of calcium as intracellular messenger, calcium release or entry across the plasma membrane, calcium in neurotransmitter release, and the regulation of free calmodulin levels in neurons by neuromodulin. Other papers discuss the calcium/calmodulin-dependent protein kinase II, the regulation of muscular calcium channels, and the Na+-Ca2+ exchangers. One paper describes the mechanisms of intracellular calcium release or entry in which agonists acting through the phosphoinositide system, or possibly by metabolites or secondary messenger system,can regulate the mechanisms of cellular Ca2+. Another paper describes different approaches in evaluating the possible mechanisms of calcium in neurotransmitter release. The paper notes that imaging techniques can be used in the timing and order of events in the release process. Possible identification by the investigator of specific "releasing" regions at the membranes, such as active zones, can also define more precisely the exact localization of the process. One paper discusses the interaction between released calmodulin and cytoskeleton proteins that can affect polymerization and cross-linking of cytoskeleton polymers, that leads to filopodia formation or extension. The collection will prove beneficial to molecular biologists, general biologists, microbiologists, biochemists, and researchers involved in cellular biology.

Inhalt

Calcium as Intracellular Messenger: From Simplicity to Complexity
I. Introduction
II. The Simplicity of Ca2+ as Messenger
III. Ca2+ and Cylic AMP as Synarchic Messengers
IV. Ca2+ Metabolism and Calcium Homeostasis During Sustained Cellular Responses
V. Ca2+ as Messenger in Sustained Cellular Responses
VI. Time-Dependent Changes in Cell Responsiveness
VII. The Complexity and Elegance of Ca2+ Messenger Generation, Readout, and Action
References
The Integration of Receptor-Regulated Intracellular Calcium Release and Calcium Entry Across the Plasma Membrane
I. Introduction
II. Sources of Activator Calcium
III. Mechanisms of Intracellular Calcium Release
IV. Mechanisms of Calcium Entry
V. Conclusions
References
The Role of Calcium in Neurotransmitter Release: Existing Models and New Approaches to Evaluate Possible Mechanisms
I. Introduction
II. Current Models of the Mechanism of Synaptic Release
III. Experimental Models and Techniques Applied to the Study of Secretion
IV. Role of Second Messengers in Exocytosis
V. Concluding Remarks
References
Regulation of Free Calmodulin Levels in Neurons by Neuromodulin: Relationship to Neuronal Growth and Regeneration
I. Discovery of Neuromodulin as a Calmodulin-Binding Protein
II. Distribution of Neuromodulin within Brain
III. Physical Properties of Neuromodulin
IV. Primary Amino Acid Sequence of Neuromodulin and Identification of Its Calmodulin-Binding Domain
V. Regulation of Calmodulin Binding to Neuromodulin by Protein Kinase C Phosphorylation and Calcineurin Dephosphorylation
VI. Cloning of cDNAs Encoding Neuromodulin and Expression of the Protein in Escherichia coli
VII. Recognition of the Homology Between Neuromodulin and GAP-43; Physiological Functions of the Protein
VIII. Biochemical Model for Regulation of Neurite Extension by Neuromodulin
References
Calcium/Calmodulin-Dependent Protein Kinase II
I. Introduction
II. The CaM Kinase II Isozyme Family
III. Substrate Consensus Phosphorylation Sequence
IV. Regulatory Properties of CaM Kinase II
V. Identification of Regulatory Domains of CaM Kinase II
VI. Physiological Role of CaM Kinase II
VII. Summary
References
The Molecular Structure and Regulation of Muscular Calcium Channels
I. Introduction
II. Composition of the Skeletal Muscle CaCB Receptor/Calcium Channel
III. Primary Sequence of the Channel Subunits
IV. Binding Characteristics of the Purified Channel
V. Reconstitution of the Calcium Channel Receptor Complex and Its Physiological Function
VI. Structure of Nonskeletal Muscle L-Type Calcium Channels
VII. In Vivo Regulation and Conclusion
References
Na+-Ca2+ Exchanger: The Elusive Protein
I. Introduction
II. The Beginning: How It All Started
III. Stoichiometry and the Effect of Membrane Potential on Na+-Ca2+ Exchanger
IV. The Modulating Role of ATP in Na+-Ca2+ Exchange
V. Purification of the Na+-Ca2+ Exchanger
VI. Expression of Na+-Ca2+ Exchange Activity in Xenopus Oocytes
VII. Conclusions
References
Index