Cell Signaling by
Cell Signaling presents the principles and components that underlie all known signaling processes. It provides undergraduate and graduate students the conceptual tools needed to make sense of the dizzying array of pathways used by the cell to communicate. By emphasizing the common design principles, components, and logic that drives all signaling, the book develops a conceptual framework through which students can understand how thousands of diverse signaling proteins interact with each other in vast interconnected networks. The book first examines the common currencies of cellular information processing and the core components of the signaling machinery. It then shows how these individual components link together into networks and pathways to perform more sophisticated tasks. Many specific examples are provided throughout to illustrate common principles, and provide a comprehensive overview of major eukaryotic signaling pathways.
Protein Movement Across Membranes by
This book addresses the most recent advances in the transport of proteins across a variety of biological membranes. In addressing this topic, this volume includes several new twists not previously addressed in the literature. In the last few years, the study of protein translocation has been revolutionized by the availability of structural information on many of the components and complexes involved in the process. Unlike earlier books written on protein translocation, this volume considers these advances. In addition, several chapters discuss facets of protein translocation from a systems biology perspective, considered by many to be the next paradigm for biological study. Readers of this book will come away with a deeper understanding of the problems facing researchers of protein translocation and see how the most modern biological techniques and approaches are being recruited to answer those questions. The chapters are also written such that problems awaiting future investigation are clearly presented.
Membrane Trafficking in Viral Replication by
Viruses are major pathogens in humans, and in the organisms with which we share this planet. The massive health and economic burden these agents impose has spurred a huge research effort to understand their most intimate details. One outcome of this effort has been the production, in many but certainly not all cases, of effective vaccines and therapies. - other consequence has been the realization that we can exploit viruses and put them to work on our behalf. Viruses are still seen to have the most - tential as vehicles for gene delivery and other therapeutic applications. However, their ability to exploit cellular functions to their own ends makes viruses not only highly effective pathogens but also exquisite experimental tools. Work with viruses underpins much of our current understanding of molecular cell biology and related fields. For membrane traffic in parti- lar, viruses have been crucial in providing insights into key cellular fu- tions and the molecular mechanisms underlying these events.
Plasma membranes surround cells, (plant cells also have a cell wall). Membranes are selectively permeable (only allow certain molecules through) and are roughly 10 nm thick.
Membranes are made of phospholipid and protein, arranged in a fluid mosaic. There are two layers of phospholipid, with large protein molecules floating in this oily layer (most proteins go all the way across the membrane). "Fluid" means that the membrane is liquid. "Mosaic" refers to the proteins scattered around like mosaic tiles on a floor. Diagram
Unsaturated fatty acids make the membrane fluid.
Saturated fatty acids make the membrane viscous (so it does not change shape easily).
Cholesterol is added to some membranes as an antifreeze; organisms living in cold climates can survive temperatures below freezing because their membranes stay fluid.
Proteins in the membrane have many functions including : transport, enzymes, receptors for hormones and joining cells together.
Carbohydrates (oligosaccharides) on the outside of the membrane let the immune system identify the cell.
These carbohydrates are important in organ transplants: the donor organ has to match (as closely as possible) the recipient.
Passive transport : the cell uses no energy. Passive transport includes diffusion and osmosis.
Diffusion : the movement of molecules from high concentration to low concentration ( liquid or gas ).
Cells get a lot of materials like glucose and oxygen by diffusion.
Osmosis : the diffusion of water through a selectively permeable membrane.