Ca2+ signaling in neurons is characterized by highly restricted and dynamic gradients called Ca2+ waves, spikes, transients and puffs depending upon their corresponding spatial and temporal features. Based on this strict segmentation the Ca2+ ion provides a versatile basis for complex signaling in neuronal subcompartments with a spatial resolution of micro- and nanodomains. The multitude of Ca2+-regulated processes requires specialized downstream processing machinery, translating the Ca2+ signal into alterations of cellular processes. The broad range of different Ca2+-triggered phenomena in neurons, ranging from neurotransmission to gene expression, is reflected by the existence of a multitude of different Ca2+-binding proteins (CaBPs) from which numerous belong to the EF-hand super-family. EF-hand proteins can be subdivided into Ca2+ buffer and Ca2+ sensor proteins. Whereas the first group has a very high affinity for Ca2+, exhibits little conformational change in the Ca2+-bound state and is thought to mainly chelate Ca2+, the second group has a lower affinity for Ca2+ and shows considerable conformational changes upon Ca2+-binding, which usually triggers a target interaction. Neuronal calcium sensor (NCS) proteins and the related Caldendrin/CaBP/Calneuron (nCaBPs) proteins are members of this latter group. They resemble the structure of their common ancestor Calmodulin (CaM) with four EF-hand Ca2+-binding motifs, of which not all are functional. However, despite their structural homology with CaM, NCS as well as nCaBPs are quite diverse in amino acid sequence. It is therefore surprising that relatively few binding partners have been identified that are not CaM targets and this raises the question of the specificity and function of these interactions. In terms of function, binding of NCS and nCaBP has frequently different consequences than binding of CaM, which substantially increases the versatility of the Ca2+ tool kit. The general idea of this special issue is to provide an overview on the function of neuronal EF-hand calcium-binding proteins in health and disease. But we will not just provide a mere collection of articles to stress the function of each protein. The issue will mainly deal with emerging concepts on Ca2+-signaling/buffering mediated by EF-hand Ca2+-binding proteins. This includes questions like features that define the functional role of a EF-hand calcium sensor in neurons, the conditions that make physiological relevance of a given interaction of a CaBP with its target plausible, the emerging synaptic role of these proteins, and mounting evidence for their role in the regulation of protein trafficking. Structural aspects and biophysical studies will be covered. Another aspect will be the role of CaBPs in brain disease states. This aspect includes studies showing that CaBPs are targets of drugs in clinical use, studies showing that expression levels of calcium-binding proteins are frequently altered in brain disease states as well as reports on mutations in EF-hand calcium sensors linked to human disease.

Calcium Transport Elements in Plants discusses the role of calcium in plant development and stress signaling, the mechanism of Ca2+ homeostasis across plant membranes, and the evolution of Ca2+/cation antiporter (CaCA) superfamily proteins. Additional sections cover genome-wide analysis of Annexins and their roles in plants, the roles of calmodulin in abiotic stress responses, calcium transport in relation to plant nutrition/biofortification, and much more. Written by leading experts in the field, this title is an essential resource for students and researchers that need all of the information on calcium transport elements in one place. Calcium transport elements are involved in various structural, physiological and biochemical processes or signal transduction pathways in response to various abiotic and biotic stimuli. Development of high throughput sequencing technology has favored the identification and characterization of numerous gene families in plants in recent years, including the calcium transport elements. Provides a complete compilation of detailed information on Ca2+ efflux and influx transporters in plants Discusses the mode of action of calcium transport elements and their classification Explores the indispensable role of Ca2+ in numerous developmental and stress related pathways

This volume contains a unique selection of chapters covering a wealth of contemporary topics in this ubiquitous and diverse system of cell signaling. It offers much more than the accessibility and authority of a primary text book, exploring topics ranging from the fundamental aspects of calcium signaling to its varied clinical implications. It presents comprehensive discussion of cutting-edge research alongside detailed analysis of critical issues, at the same time as setting out testable hypotheses that point the way to future scientific endeavors. The contributions feature material on theoretical and methodological topics as well as related subjects including mathematical modeling and simulations. They examine calcium signaling in a host of contexts, from mammalian cells to bacteria, fruit fly and zebrafish. With much of interest to newcomers to the field as well as seasoned experts, this new publication is both wide-ranging and authoritative. The chapter “Calcium Signaling: From Basic to Bedside” is available open access under a Creative Commons Attribution 4.0 International License via link.springer.com.

With the invitation to edit this volume, I wanted to take the opportunity to assemble reviews on different aspects of circadian clocks and rhythms. Although most c- tributions in this volume focus on mammalian circadian clocks, the historical int- duction and comparative clocks section illustrate the importance of various other organisms in deciphering the mechanisms and principles of circadian biology. Circadian rhythms have been studied for centuries, but only recently, a mole- lar understanding of this process has emerged. This has taken research on circadian clocks from mystic phenomenology to a mechanistic level; chains of molecular events can describe phenomena with remarkable accuracy. Nevertheless, current models of the functioning of circadian clocks are still rudimentary. This is not due to the faultiness of discovered mechanisms, but due to the lack of undiscovered processes involved in contributing to circadian rhythmicity. We know for example, that the general circadian mechanism is not regulated equally in all tissues of m- mals. Hence, a lot still needs to be discovered to get a full understanding of cir- dian rhythms at the systems level. In this respect, technology has advanced at high speed in the last years and provided us with data illustrating the sheer complexity of regulation of physiological processes in organisms. To handle this information, computer aided integration of the results is of utmost importance in order to d- cover novel concepts that ultimately need to be tested experimentally.

Calcium Entry Channels in Non-Excitable Cells focuses on methods of investigating the structure and function of non-voltage gated calcium channels. Each chapter presents important discoveries in calcium entry pathways, specifically dealing with the molecular identification of store-operated calcium channels which were reviewed by earlier volumes in the Methods in Signal Transduction series. Crystallographic and pharmacological approaches to the study of calcium channels of epithelial cells are also discussed. Calcium ion is a messenger in most cell types. Whereas voltage gated calcium channels have been studied extensively, the non-voltage gated calcium entry channel genes have only been identified relatively recently. The book will fill this important niche.

Bio-Nanoimaging: Protein Misfolding & Aggregation provides a unique introduction to both novel and established nanoimaging techniques for visualization and characterization of misfolded and aggregated protein species. The book is divided into three sections covering: - Nanotechnology and nanoimaging technology, including cryoelectron microscopy of beta(2)-microglobulin, studying amyloidogensis by FRET; and scanning tunneling microscopy of protein deposits - Polymorphisms of protein misfolded and aggregated species, including fibrillar polymorphism, amyloid-like protofibrils, and insulin oligomers - Polymorphisms of misfolding and aggregation processes, including multiple pathways of lysozyme aggregation, misfolded intermediate of a PDZ domain, and micelle formation by human islet amyloid polypeptide Protein misfolding and aggregation is a fast-growing frontier in molecular medicine and protein chemistry. Related disorders include cataracts, arthritis, cystic fibrosis, late-onset diabetes mellitus, and numerous neurodegenerative diseases like Alzheimer's and Parkinson's. Nanoimaging technology has proved crucial in understanding protein-misfolding pathologies and in potential drug design aimed at the inhibition or reversal of protein aggregation. Using these technologies, researchers can monitor the aggregation process, visualize protein aggregates and analyze their properties. - Provides practical examples of nanoimaging research from leading molecular biology, cell biology, protein chemistry, biotechnology, genetics, and pharmaceutical labs - Includes over 200 color images to illustrate the power of various nanoimaging technologies - Focuses on nanoimaging techniques applied to protein misfolding and aggregation in molecular medicine