Aquaporins (AQPs), a class of integral membrane proteins, form channels facilitating movement of water and many other solutes. In solute transport systems of all living organisms including plants, animals and fungi, AQPs play a vital role. Plants contain a much higher number of AQP genes compared to animals, the likely consequence of genome duplication events and higher ploidy levels. As a result of duplication and subsequent diversification, plant AQPs have evolved several subfamilies with very diverse functions. Plant AQPs are highly selective for specific solutes because of their unique structural features. For instance, ar/R selectivity filters and NPA domains have been found to be key elements in governing solute permeability through the AQP channels. Combination of conserved motifs and specific amino acids influencing pore morphology appears to regulate the permeability of specific solutes such as water, urea, CO2, H2O2, boric acid, silicic acid and many more. The discovery of novel AQPs has been accelerated over the last few years with the increasing availability of genomic and transcriptomic data. The expanding number of well characterised AQPs provides opportunities to understand factors influencing water transport, nutritional uptake, and elemental balance. Homology-based search tools and phylogenetic analyses offer efficient strategies for AQP identification. Subsequent characterization can be based on different approaches involving proteomics, genomics, and transcriptomic tools. The combination of these technological advances make it possible to efficiently study the inter-dependency of AQPs, regulation through phosphorylation and reversible phosphorylation, networking with other transporters, structural features, pH gating systems, trafficking and degradation. Several studies have supported the role of AQPs in differential phenotypic responses to abiotic and biotic stress in plants. Crop improvement programs aiming for the development of cultivars with higher tolerance against stresses like drought, flooding, salinity and many biotic diseases, can explore and exploit the finely tuned AQP-regulated transport system. For instance, a promising approach in crop breeding programs is the utilization of genetic variation in AQPs for the development of stress tolerant cultivars. Similarly, transgenic and mutagenesis approaches provide an opportunity to better understand the AQP transport system with subsequent applications for the development of climate-smart drought-tolerant cultivars. The contributions to this Frontiers in Plant Science Research Topic have highlighted the evolution and phylogenetic distribution of AQPs in several plant species. Numerous aspects of regulation that seek to explain AQP-mediated transport system have been addressed. These contributions will help to improve our understanding of AQPs and their role in important physiological aspects and will bring AQP research closer to practical applications.

Aquaporins are channel proteins that facilitate the diffusion of water and small uncharged solutes across cellular membranes. Plant aquaporins form a large family of highly divergent proteins that are involved in many different physiological processes. This book will summarize the recent advances regarding plant aquaporins, their phylogeny, structure, substrate specificity, mechanisms of regulation and roles in various important physiological processes related to the control of water flow and small solute distribution at the cell, tissue and plant level in an ever-changing environment.

Aquaporin Regulation, Volume 112, the latest release in the Vitamins and Hormones series, highlights new advances in the field, with this new volume presenting interesting chapters highlighting Perspectives on the evolution of aquaporin superfamily, Structure and dynamics of aquaporin-1, Selectivity and Transport in Aquaporins from Molecular Simulation Studies, Aquaporin regulation in metabolic organs, Phosphorylation of human AQP2 and its role in trafficking, Regulation of Aquaporin-2 by RNA Interference, Aquaporin Regulation: Lessons from Secretory Vesicles, CFTR Regulation of Aquaporin-mediated Water Transport, Glucocorticoid Gene Regulation of Aquaporin-7, and much more.

Since the discovery of Aquaporin-1 (AQP1) as a water channel, many studies have revealed the importance of aquaporins in mammalian physiology and pathophysiology as well as plant and microbial biology. The studies have also shown aquaporins as potential drug targets and targets for improving crop properties. Written by an international group of contributors at the forefront of the field, Aquaporins in Health and Disease: New Molecular Targets for Drug Discovery presents the latest research advances in aquaporins and other major intrinsic protein (MIP) channels. The first section of the book describes the general concepts of aquaporin channel function, genomic research, structure-function analysis of aquaporins and glycerol facilitators, and regulation by gating and trafficking, including yeast aquaporin regulation and function. The second section discusses the physiological and pathophysiological roles of aquaporins in humans and microbes. The final section covers the development of inhibitors of aquaporin function. The book’s epilogue offers future perspectives and directions, mainly in the area of aquaporin-based diagnostics and therapeutics. Stimulating future research on this important protein family, this book facilitates a paradigm shift in the understanding and roles of aquaporin membrane proteins in all biological settings. It encourages scientists to develop novel approaches for the treatment of human diseases based on aquaporin function or dysfunction.

The aquaporin field has matured at an exceptionally fast pace and we are at the verge to develop serious strategies to therapeutically modulate aquaporin function directly or via regulatory networks. Key prerequisites are available today: i. a considerable (and growing) number of aquaporin crystal structures for the rational design of inhibitory molecules, ii. elaborate molecular dynamics simulation techniques for theoretical analyses of selectivity mechanisms and docking experiments, iii. comprehensive data on aquaporin immunohistochemistry, iv. aquaporin knockout animals for physiological studies, and v. assay systems for compound library screenings. The structure of this volume on aquaporins follows the points laid out above and thus covers the developments from basic research to potential pharmacological use. Situated between pharmacology textbooks and recent scientific papers this book provides a timely overview for readers from the fundamental as well as the applied disciplines.

This book provides a state-of-the-art report on our current understanding of aquaporins and the future direction of the field. Aquaporins (AQPs) are a group of water-channel proteins that are specifically permeable to water and other small molecules, such as glycerol and urea. To date thirteen water-channel proteins (AQP0 – AQP12) have been cloned and the mechanisms and physiological functions of water transport across biological membranes have long been the subject of interest. Recent advances in the molecular biology and physiology of water transport have yielded new insights into how and why water moves across cell membranes, and studies on aquaporin knockout mouse models suggest that aquaporins are involved in the development of some diseases and they may be useful targets of research into selective-inhibitor drugs. By focusing on the advances made over the last 30 years in the biophysics, genetics, protein structure, molecular biology, physiology, pathophysiology and pharmacology of aquaporins in mammalian cell membranes, this book provides novel insights into further mechanisms and the physiological significance of water and some small molecule transport in mammals in order to stimulate further research in new directions. In the second version, fourteen chapters will be updated base on the most recent research articles. Ten new chapters will be added.

This edited book stands as a one place knowledge hub for plant metal(loid) transporters. The book comprehensively covers holistic aspect of metal(loid) transporters involved in uptake and translocation of essential as well as toxic metal(loid)s. Essential and beneficial metal(loid)s are required in every biological process for normal plant growth and development, however in excess they are toxic. There are toxic metal(loid)s also whose accumulation in plants interferes with normal cellular functioning and hampers growth of plants. Hence, metal(loid) uptake and accumulation in plants is a highly regulated phenomenon involving the role of several transporters, enzymes, metabolites, transcription factors and post translational modifications. The book contains chapters from the experts and the contents of the book are presented in simple language and represented through beautiful and scientifically informative figures and tables. This book is of interest to teachers, researchers, doctoral and graduate students working in the area of plant physiology, environmental biotechnology, plant biotechnology metal(loid) stress, phytoremediation and crop biofortification.

Soil salinity is a key abiotic-stress and poses serious threats to crop yields and quality of produce. Owing to the underlying complexity, conventional breeding programs have met with limited success. Even genetic engineering approaches, via transferring/overexpressing a single ‘direct action gene’ per event did not yield optimal results. Nevertheless, the biotechnological advents in last decade coupled with the availability of genomic sequences of major crops and model plants have opened new vistas for understanding salinity-responses and improving salinity tolerance in important glycophytic crops. Our goal is to summarize these findings for those who wish to understand and target the molecular mechanisms for producing salt-tolerant and high-yielding crops. Through this 2-volume book series, we critically assess the potential venues for imparting salt stress tolerance to major crops in the post-genomic era. Accordingly, perspectives on improving crop salinity tolerance by targeting the sensory, ion-transport and signaling mechanisms are presented here in volume 1. Volume 2 will focus on the potency of post-genomic era tools that include RNAi, genomic intervention, genome editing and systems biology approaches for producing salt tolerant crops.

Aquaporin Regulation, Volume 112, the latest release in the Vitamins and Hormones series, highlights new advances in the field, with this new volume presenting interesting chapters highlighting Perspectives on the evolution of aquaporin superfamily, Structure and dynamics of aquaporin-1, Selectivity and Transport in Aquaporins from Molecular Simulation Studies, Aquaporin regulation in metabolic organs, Phosphorylation of human AQP2 and its role in trafficking, Regulation of Aquaporin-2 by RNA Interference, Aquaporin Regulation: Lessons from Secretory Vesicles, CFTR Regulation of Aquaporin-mediated Water Transport, Glucocorticoid Gene Regulation of Aquaporin-7, and much more. - Provides the authority and expertise of leading contributors from an international board of authors - Presents the latest release in the Vitamins and Hormones series - Updated release includes the latest information on aquaporin regulation