From Ion Channels To Cell To Cell Conversations

Ion channels allow us to see nature in all its magnificence, to hear a Bach suite, to smell the aroma of grandmother's cooking, and, in this regard, they put us in contact with the external world. These ion channels are protein molecules located in the cell membrane. In complex organisms, cells need to communicate in order to know about their metabolic status and to act in a coordinate manner. The latter is also accomplished by a class of ion channels able to pierce the lipid bilayer membranes of two adjacent cells. These intercellular channels are the functional subunits of gap junctions. Accordingly, the book is divided in two parts: the first part is dedicated to ion channels that look to the external world, and the second part is dedicated to gap junctions found at cell interfaces. This book is based on a series of symposia for a meeting on ion channels and gap junctions held in Santiago, Chile, on November 28-30, 1995. The book should be useful to graduate students taking the first steps in this field as well as a reference for the aficionado. The aim of the meeting was mainly to show the impact of various modern techniques, including cell biology, molecular biology, biophysics, and molecular genetics techniques in the study of these ubiquitous intrinsic membrane proteins. Molecular-genetics techniques paved the road to the manipulation of the channel forming molecules.

Ion channels are crucial components of living cells. Situated in the cell's membranes. they allow particular ions to pass from one side of the membrane to the other. In recent years the patch clamp technique has allowed the activity of individual channels to be measured, and recombinant DNA technology has led to fascinating detail on their structure. Together, these technical advances have produced a great flowering of knowledge and understanding about the subject, itself leading to further breakthroughs in science and medicine. Ion Channels provides an introduction to this scientific endeavour. It emphasises the molecular structure of channels as determined by gene cloning technology. This knowledge illuminates discussions of the permeability and selectivity of channels, their gating and modulation, their responses to drugs and toxins and the human diseases caused when they do not function properly.

This book is a compilation of articles based on some of the talks given at the Centro de Estudios Cientificos (CECS) in Valdivia during the course of a celebration to th mark the 60 birthdays of Ramon Latorre and Enrico Stefani. Ramon Latorre is one of the most outstanding figures in channel Biophysics today. The first surprise is that he trained as a Biochemist! He soon, however, became a biophysicist through his work with Guayo (Eduardo) Rojas who guided him during his Ph. D thesis in the Laboratorio de Fisiologia Celular in Montemar. His work at N.I.H with Gerald Eherenstein and Harold Lecar constitutes one of the milestones of single ion channel Biophysics. This classical work, done in planar bilayers, set the basis for understanding voltage-dependent conductances with single channel studies and predates, by many years, later studies using patch clamping techniques. Ramon was one of the firsts to find and recognize the importance of calci- activated potassium channels and to begin a detailed study of channel properties. He pioneered the ideas of voltage and calcium modulation of the open probability and he added detailed studies of gating and its modulation by other ions. Ramon is also interested in permeation and selectivity and he produced classical studies on the number of water molecules in the channel and sites occupied by barium. Results and concepts that have recently taken front page as the structure of KcSa has been described.

This Methods in Molecular Biology book offers strategies and protocols for studying a large group of proteins that form ionic channels in the plasma membrane and intracellular membranes of cells. Includes step-by-step protocols, materials lists, tips and more."

Cell Volume Regulation and Fluid Secretion, Volume 81, the latest release in the Current Topics in Membranes series highlights new advances in the field, with this new volume presenting interesting chapters on General principles of cell volume regulation, Cell volume maintenance: water and salt homeostasis, The search for ubiquitous cell volume sensor: the role of plasma membrane and cytoplasmic hydrogel, More than membranes, Cellular and membrane biomechanics of CVR response, Molecular identities of volume-regulatory anion channels, Molecular biology and physiology of volume-regulated anion channel (VRAC), the Role of WNKs in the modulation of intracellular chloride, amongst other topics. Provides the authority and expertise of leading contributors from an international board of authors Presents the latest release in the Current Topics in Membranes series Includes the latest information on Cell Volume Regulation

Plants live in a constantly changing environment from which they cannot physically escape. Plants therefore need signalling and response mechanisms to adapt to new local conditions. The ef?cacy of such mechanisms underlies the plant performance during stress and therefore also impacts greatly on agricultural productivity. M- ulation of ion channel activity not only provides a means for rapid signal generation 2+ but also allows adjustment of cellular physiology. For example, Ca permeable ion 2+ channels can transduce environmental stimuli into Ca -encoded messages which can modify the gene expression. Furthermore, ion channel activity is essential to control cellular ion homeostasis that impacts on plant responses to drought, salinity, pathogens, nutrient de?ciency, heavy metals, xenobiotics and other stresses. This volume focuses on the crucial roles of different types of ion channel in plant stress responses. Functions of ion channels are discussed in the context of mechanisms to relay external and endogenous signals during stress and as mechanisms to regulate cellular ion homeostasis and enzymatic activities in the context of biotic and abiotic stress. The chapters presented cover cation and anion channels located in various cellular compartments and tissues.

Voltage-sensitive ion channels are macromolecules embedded in the membranes of nerve and muscle fibers of animals. Despite decades of intensive research under the traditional approach of gated structural pores, the relation between the structure of these molecules and their function remains enigmatic. This book examines physically oriented approaches not covered in other ion-channel books, and it develops a new physics-based approach to the problem of molecular excitability.

This new, fully revised and expanded edition of Ionic Channels of Excitable Membranes includes new chapters on fast chemical synapses, modulation through G protein coupled receptors and second messenger systems, molecules cloning, site directed mutagenesis, and cell biology. It begins with the classical biophysical work of Hodgkin and Huxley and then weaves a description of the known ionic channels together with their biological functions. The book continues by developing the physical and molecular principles needed for explaining permeation, gating, pharmacological modification, and molecular diversity, and ends with a discussion of channel evolution. Ionic Channels of Excitable Membranes is written to be accessible and interesting to biological and physical scientists of all kinds.