The Role Of Biomembranes And Biophysics In Immune Cell Signaling

Transmembrane signaling is one of the most significant cell biological events in the life and death of cells in general and lymphocytes in particular. Until recently biochemists and biophysicists were not accustomed to thinking of these processes from the side of a high number of complex biochemical events and an equally high number of physical changes at molecular and cellular levels at the same time. Both types of researchers were convinced that their findings are the most decisive, having higher importance than the findings of the other scientist population. Both casts were wrong. Life, even at cellular level, has a number of interacting physical and biochemical mechanisms, which finally build up the creation of an "excited" cell that will respond to particular signals from the outer or inner world. This book handles both aspects of the signalling events, and in some cases tries to unify our concepts and help understand the signals that govern the life and death of our cells. Not only the understanding, but also the interference (e.g. medication) may depend on the full knowledge of both sides. These above statements are supported by the application of highly diverse physical and biochemical technologies demonstrated and explained by experts who are pioneers of their particular scientific field.

Phase transitions occur throughout nature. The most familiar example is the one that occurs in water – the abrupt, discontinuous transition from a liquid to a gas or a solid, induced by a subtle environmental change. Practically magical, the ever-so-slight shift of temperature or pressure can induce an astonishing transition from one entity to another entity that bears little resemblance to the first. So "convenient" a feature is seen throughout the domains of physics and chemistry, and one is therefore led to wonder whether it might also be common to biology. Indeed, many of the most fundamental cellular processes are arguably attributable to radical structural shifts triggered by subtle changes that cross a critical threshold. These processes include transport, motion, signaling, division, and other fundamental aspects of cellular function. Largely on the basis of this radical concept, a symposium was organized in Poitiers, France, to bring together people who have additional evidence for the role of phase transitions in biology, and this book is a compendium of some of the more far-reaching of those presentations, as well as several others that seemed to the editors to be compelling. The book should be suitable for anyone interested in the nature of biological function, particularly those who tire of lumbering along well trodden pathways of pursuit, and are eager to hear something fresh. The book is replete with fresh interpretations of familiar phenomena, and should serve as an excellent gateway to deeper understanding.

This volume focuses on the modulation of biological membranes by specific biophysical properties. The readers are introduced to emerging biophysical approaches that mimick specific states (like membrane lipid asymmetry, membrane curvature, lipid flip-flop, lipid phase separation) that are relevant to the functioning of biological membranes. The first chapter describes innovative methods to mimic the prevailing asymmetry in biological membranes by forming asymmetrical membranes made of monolayers with different compositions. One of the chapters illustrates how physical parameters, like curvature and elasticity, can affect and modulate the interactions between lipids and proteins. This volume also describes the sensitivity of certain ion channels to mechanical forces and it presents an analysis of how cell shape is determined by both the cytoskeleton and the lipid domains in the membrane. The last chapter provides evidence that liposomes can be used as a minimal cellular model to reconstitute processes related to the origin of life. Each topic covered in this volume is presented by leading experts in the field who are able to present clear, authoritative and up-to-date reviews. The novelty of the methods proposed and their potential for a deeper molecular description of membrane functioning are particularly relevant experts in the areas of biochemistry, biophysics and cell biology, while also presenting clear and thorough introductions, making the material suitable for students in these fields as well.

Biological membranes protect cells and organelles from the surrounding environment, but serve also as organising platforms for physiological processes such as cell signalling. The hydrophobic core of membranes is composed of lipids and proteins influencing each other. Local membrane composition and properties define its molecular organisation and, in this way, regulate the function of all associated molecules. Therefore, studying interactions of components, biophysical properties and overall membrane dynamics provides essential information on its function in the context of cell activities. Such knowledge can contribute to biomedical fields such as pharmacology, immunology, neurobiology and many others. The goal of the Research Topic entitled ‘Molecular organisation of membranes: where biology meets biophysics’ was to provide a comprehensive platform for publishing articles, reviews and opinions focused on membrane organisation and the forces behind its heterogeneous and dynamic structure. We collected 11 works which cover topics as diverse as general membrane organisation models, membrane trafficking and signalling regulation, biogenesis of caveolae, protein-lipid interactions and the importance of membrane-associated tetraspanins networks. The prevalent theme was the existence of membrane nanodomains. To this point, new emerging technologies are presented which own the power to bring a novel insight on how membrane nanodomains are formed and maintained and what is their function. We believe that the collection of works in this Research Topic brings forward some important questions which will stimulate further research in this difficult but exciting field.

A comprehensive volume on interfacial catalysis, this book includes contributions from an international group of specialists in chemistry, environmental science, informatics, physiology, nuclear energy, and physics. The editor has organized the material into the main topics of fundamental characteristics, phase transfer catalysis, reversed micelles, biological aspects, and interfacial photocatalysis. Individual topics include self-organized microheterogeneous structures, nanochemistry, interfacial catalysis in metal complexation, the role of water molecules in ion transfer at the oil/water interface, and ultrathin films in enhanced oil recovery.