This volume brings together a set of reviews that provide a summary of our current knowledge of the proteolytic machinery and of the pathways of protein breakdown of prokaryotic and eukaryotic cells. Intracellular protein degradation is much more than just a mechanism for the removal of incorrectly folded or damaged proteins. Since many short-lived proteins have important regulatory functions, proteolysis makes a significant contribution to many cellular processes including cell cycle regulation and transciptional control. In addition, limited proteolytic cleavage can provide a rapid and efficient mechanism of enzyme activation or inactivation in eukaryotic cells. In the first chapter, Maurizi provides an introduction to intracellular protein degradation, describes the structure and functions of bacterial ATP-dependent proteases, and explores the relationship between chaperone functions and protein degradation. Many of the principles also apply to eukaryotic cells, although the proteases involved are often not the same. Interestingly, homologues of one of the bacterial proteases, Ion protease, have been found in mitochondria in yeast and mammals, and homologues of proteasomes, which are found in all eukaryotic cells (see below), have been discovered in some eubacteria. Studies of proteolysis in yeast have contributed greatly to the elucidation of both lysosomal (vacuolar) and nonlysosomal proteolytic pathways in eukaryotic cells. Thumm and Wolf (chapter 2) describe studies that have elucidated the functions of proteasomes in nonlysosomal proteolysis and the contributions of lysosomal proteases to intracellular protein breakdown. Proteins can be selected for degradation by a variety of differen mechanisms. The ubiquitin system is one complex and highly regulated mechanism by which eukaryotic proteins are targetted for degradation by proteosomes. In chapter 3, Wilkinson reviews the components and functions of the ubiquitin system and considers some of the known substrates for this pathway which include cell cycle and transcriptional regulators. The structure and functions of proteosomes and their regulatory components are described in the two subsequent chapters by Tanaka and Tanahashi and by Dubiel and Rechsteiner. Proteasomes were the first known example of threonine proteases. They are multisubunit complexes that, in addition to being responsible for the turnover of most short-lived nuclear and cytoplasmic protein, are also involved in antigen processing for presentation by the MHC class I pathway. Recent studies reviewed by McCracken and colleagues (chapter 6) lead to the exciting conclusion that some ER-associated proteins are degraded by cytosolic proteasomes. Lysosomes are responsible for the degradation of long-lived proteins and for the enhanced protein degradation observed under starvation conditions. In chapter 7 Knecht and colleagues review the lysosomal proteases and describe studies of the roles of lysosomes and the mechanisms for protein uptake into lysosomes. Methods of measuring the relative contribution of different proteolytic systems (e.g., ubiquitin-proteasome pathway, calcium-dependent proteases, lysosomes) to muscle protein degradation, and the conclusions from such studies, are reviewed by Attai and Taillinder in the following chapter. Finally, proteases play an important role in signaling apoptosis by catalyzing the limited cleavage of enzymes. Mason and Beyette review the role of the major players, caspases, which are both activated by and catalyze limite proteolysis, and also consider the involvement of other protoelytic enzymes in this pathway leading cell death.

Bridging the gap between basic scientific advances and the understanding of liver disease — the extensively revised new edition of the premier text in the field. The latest edition of The Liver: Biology and Pathobiology remains a definitive volume in the field of hepatology, relating advances in biomedical sciences and engineering to understanding of liver structure, function, and disease pathology and treatment. Contributions from leading researchers examine the cell biology of the liver, the pathobiology of liver disease, the liver’s growth, regeneration, metabolic functions, and more. Now in its sixth edition, this classic text has been exhaustively revised to reflect new discoveries in biology and their influence on diagnosing, managing, and preventing liver disease. Seventy new chapters — including substantial original sections on liver cancer and groundbreaking advances that will have significant impact on hepatology — provide comprehensive, fully up-to-date coverage of both the current state and future direction of hepatology. Topics include liver RNA structure and function, gene editing, single-cell and single-molecule genomic analyses, the molecular biology of hepatitis, drug interactions and engineered drug design, and liver disease mechanisms and therapies. Edited by globally-recognized experts in the field, this authoritative volume: Relates molecular physiology to understanding disease pathology and treatment Links the science and pathology of the liver to practical clinical applications Features 16 new “Horizons” chapters that explore new and emerging science and technology Includes plentiful full-color illustrations and figures The Liver: Biology and Pathobiology, Sixth Edition is an indispensable resource for practicing and trainee hepatologists, gastroenterologists, hepatobiliary and liver transplant surgeons, and researchers and scientists in areas including hepatology, cell and molecular biology, virology, and drug metabolism.

A panel of leading academic and pharmaceutical investigators takes stock of the remarkable work that has been accomplished to date with proteasome inhibitors in cancer, and examines emerging therapeutic possibilities. The topics range from a discussion of the chemistry and cell biology of the proteasome and the rationale for proteasome inhibitors in cancer to a review of current clinical trials underway. The discussion of rationales for testing proteasome inhibitors in cancer models covers the role of the proteasome in NF-kB activation, the combining of conventional chemotherapy and radiation with proteasome inhibition, notably PS-341, new proteasome methods of inhibiting viral maturation, and the role of protesome inhibition in the treatment of AIDS. The authors also document the development of bortezomib (VelcadeTM) in Phase I clinical trials and in a multicentered Phase II clinical trials in patients with relapsed and refractory myeloma.

This volume contains a collection of innovative techniques for studying targeted protein degradation. Chapters guide readers through heterobifunctional proteolysis-targeting chimeras (PROTACs) approaches, E3 ligase, E3 ligase-induced ubiquitylation, proteomic approaches, novel degrader molecules, molecular glue, and stabilize binding interaction between a target and E3 ubiquitin ligase. Written in the format of the highly successful Methods in Molecular Biology series, each chapter includes an introduction to the topic, lists necessary materials and reagents, includes tips on troubleshooting and known pitfalls, and step-by-step, readily reproducible protocols. Authoritative and cutting-edge, Targeted Protein Degradation: Methods and Protocols aims to ensure successful results in this emerging field of drug discovery.

This book covers the past, present and future of the intra-cellular trafficking field, which has made a quantum leap in the last few decades. It details how the field has developed and evolved as well as examines future directions.

Targeting protein degradation using small molecules is one of the most exciting small-molecule therapeutic strategies in decades and a rapidly growing area of research. In particular, the development of proteolysis targeting chimera (PROTACs) as potential drugs capable of recruiting target proteins to the cellular quality control machinery for elimination has opened new avenues to address traditionally ‘difficult to target’ proteins. This book provides a comprehensive overview from the leading academic and industrial experts on recent developments, scope and limitations in this dynamically growing research area; an ideal reference work for researchers in drug discovery and chemical biology as well as advanced students.

The last several years have been a landmark period in the ubiquitin field. The breadth of ubiquitin's roles in cell biology was first sketched, and the importance of ubiquitin-dependent proteolysis as a regulatory mechanism gained general acceptance. The many strands of work that led to this new perception are re counted in this book. A consequence of this progress is that the field has grown dramatically since the first book on ubiquitin was published almost a decade ago [M. Rechsteiner (ed. ), Ubiquitin, Plenum Press, 1988]. In this span, students of the cell cycle, transcription, signal transduction, protein sorting, neuropathology, cancer, virology, and immunology have attempted to chart the role of ubi quit in in their particular experimental systems, and this integration of the field into cell biology as a whole continues at a remarkable pace. We hope that for active researchers in the field as well as for newcomers and those on the fence, this book will prove helpful for its breadth, historical perspective, and practical tips. Structural data are now available on many of the components of the ubiquitin pathway. The structures have provided basic insights into the unusual biochemical mechanisms of ubiquitination and proteasome-mediated proteolysis. Because high-speed computer graphics can convey structures more effectively than print media, we have supplemented the figures of the book with a Worldwide Web site that can display the structures in a flexible, viewer-controlled format.