DNA damage response (DDR) is a term that includes a variety of highly sophisticated mechanisms that cells have evolved in safeguarding the genome from the deleterious consequences of DNA damage. It is estimated that every single cell receives tens of thousands of DNA lesions per day. Failure of DDR to properly respond to DNA damage leads to stem cell dysfunction, accelerated ageing, various degenerative diseases or cancer. The sole function of DDR is to recognize diverse DNA lesions, signal their presence, activate cell cycle arrest and finally recruit specific DNA repair proteins to fix the DNA damage and thus prevent genomic instability. DDR is composed of hundreds of spatiotemporally regulated and interconnected proteins, which are able to promptly respond to various DNA lesions. So it is not surprising that mutations in genes encoding various DDR proteins cause embryonic lethality, malignancies, neurodegenerative diseases and premature ageing. The importance of DDR for cell survival and genome stability is unquestionable, but how the sophisticated network of hundreds of different DDR proteins is spatiotemporally coordinated is far from being understood. In the last ten years ubiquitin (ubiquitination) and the ubiquitin-relative SUMO (sumoylation) have emerged as essential posttranslational modifications that regulate DDR. Beside a plethora of ubiqutin and sumo E1-activating enzymes, E2-conjugating enzymes, E3-ligases and ubiquitin/sumo proteases involved in ubiquitination and sumoylation, the complexity of ubiqutin and sumo systems is additionally increased by the fact that both ubiquitin and sumo can form a variety of different chains on substrates which govern the substrate fate, such as its interaction with other proteins, changing its enzymatic activity or promoting substrate degradation. The importance of ubiquitin/SUMO systems in the orchestration of DDR is best illustrated in patients with mutations in E3-ubiquitin ligases BRCA1 or RNF168. BRCA1 is essential for proper function of DDR and its mutations lead to triple-negative breast and ovarian cancers. RNF168 is an E3 ubiquitin ligase, which creates the ubiquitin docking platform for recruitment of different DNA damage signalling and repair proteins at sites of DNA lesion, and its mutations cause RIDDLE syndrome characterized by radiosensitivity, immunodeficiency and learning disability. In addition, recently discovered the ubiquitin receptor protein SPRTN is part of the DNA replication machinery and its mutations cause early-onset hepatocellular carcinoma and premature ageing in humans. Despite more than 700 different enzymes directly involved in ubiquitination and sumoylation processes only few of them are known to play a role in DDR. Therefore, we feel that the role of ubiquitin and the ubiquitin-related SUMO in DDR is far from being understood, and that this is the emerging field that will hugely expand in the next decade due to the rapid development of a new generation of technologies, which will allow us a more robust and precise analyses of human genome, transcriptome and proteome. In this Research Topic we provide a comprehensive overview of our current understanding of ubiquitin and SUMO pathways in all aspects of DDR, from DNA replication to different DNA repair pathways, and demonstrate how alterations in these pathways cause genomic instability that is linked to degenerative diseases, cancer and pathological ageing.

Most proteins undergo post-translational modifications altering physical and chemical properties, folding, conformation distribution, stability, activity and function. Ubiquitin and SUMOs are related small proteins that are members of the large ubiquitin superfamily of post-translational modifiers. Written by highly respected leaders in their fields under the expert guidance of the editor, this volume covers the principles of ubiquitination and SUMOylation, presents detailed reviews of current and emerging concepts and highlights new advances in all areas of SUMOylation and ubiquitination. Topics of note include: the ubiquitin superfamily, the ubiquitin toolbox, onco viral exploitation of the SUMO system, small molecule modulators of desumoylation, mass spectrometry, global proteomic profiling of SUMO and ubiquitin, biotin-based approaches, genetic screening, SUMOylation networks in humans, targets for ubiquitin ligases, regulation of p53, protein homeostasis, miRNAs, DNA replication, DNA damage response, telomere biology, intracellular trafficking, regulation of angiogenesis, brain ischemia, autophagy, assembly and activity, antiviral defense, HIV infection, amyloid and amyloid-like proteins, plant immunity. This comprehensive and up-to-date book is the definitive reference volume on all aspects of SUMOylation and ubiquitination and is an essential acquisition for anyone involved in this area of biology.

Ubiquitination and Protein Stability - Part B, Volume 619, the latest release in the Methods in Enzymology series, highlights new advances in the field, with this updated volume presenting interesting chapters written by an international board of authors. Topics of note include chapters on Assays of SUMO protease function in mammalian cells, In vitro analysis of proteasome-associated USP14 activity for substrate degradation and deubiquitylation, Methods to study proteasome regulatory particle assembly, Native mass spectrometry approaches to study the proteasome, Single-molecule methods to study the ubiquitin-proteasome system, Assays for the function of ubiquitin in the mammalian endocytic pathway, and much more.

​​​​​​​​​​​​​While there has been an increasing number of books on various aspects of epigenetics, there has been a gap over the years in books that provide a comprehensive understanding of the fundamentals of chromatin. ​Chromatin is the combination of DNA and proteins that make up the genetic material of chromosomes. Its primary function is to package DNA to fit into the cell, to strengthen the DNA to prevent damage, to allow mitosis and meiosis, and to control the expression of genes and DNA replication. The audience for this book is mainly newly established scientists ​and graduate students. Rather than going into the more specific areas of recent research on chromatin the chapters in this book give a strong, updated groundwork about the topic. Some the fundamentals that this book will cover include the structure of chromatin and biochemistry and the enzyme complexes that manage it.

The human ubiquitin proteasome system (UPS) is comprised of nearly 1000 proteins. Although originally identified as a mechanism of protein destruction, the UPS has numerous additional functions and mediates central signaling events in myriad processes involved in both cellular and organismal health and homeostasis. Numerous pathways within the UPS are implicated in disease, ranging from cancer to neurodegenerative diseases such as Parkinson's. The goal of this book is to deliver a collection of synopses of current areas of UPS research that highlights the importance of understanding the biology of the UPS to identify disease-relevant pathways, and the need to elucidate the molecular machinations within the UPS to develop methods for therapeutic modulation of these pathways.

† 1 a a 4 † 17 10 15 ubiquitin; and of 16 VCP 17 18 20 33 34 34 36 p domain. 41 42 42 43 P U 42 47 binding. C. elegans 16 In 21 22 50 51 52 53 13 and UFD 4 10 of Cdc48. 18 30 of Ufd2. COFACTORS 47 23 13 47 47 47 72 15 15 and of Spt23 p90. Ufd2 and Cdc48. In C. elegans 74 16 75 75 76 76 Ufd2 25 54 54 7 56 p47 7 7 80 30 30 81 82 82 but and CD3 26 DUB COFACTORS 30 UFD3 OTU1 4 Cdc48 30 4 OLE1. 15 27 87 REFERENCES 30 REGULATION OF UBIQUITIN MONOUBIQUITINATION UBIQUITINATION 1 32 7 S) d 33 12 13 14 15 18 19 15 20 21 35 15 15 27 15 31 32 31 33 36 monoubiquitination of pol pol 34 37 34 monoubiquitination. 20 35 trans 3 15 REFERENCES by monoubiquitination. Mol Cell; 2009. UBIQUITIN LIGASE ACTIVITY BY Nedd 1 2 of 41 5 6 8 fold. 9 13 14 edd 43 18 18 K M and k 18 22 23 K M 24 25 K M 26 edd 45 18 27 K M K D 18 25 . 8 10 M 21 28 MECHANISM AND REGULATION OF CRLs 34 41 34 edd 47 48 S. pombe 49 51 p27 and I by SCF and SCF 57 58 59 60 CTD CTD CTD CTD in Cul5 CTD CTD CTD 60 18

This volume gives an overview of pro tea some-mediated protein degradation and the regulatory role of the ubiquitin system in cellular proteolysis. The first chapter describes the molecular evolution of the proteasome and its associated activators, i. e. , the 20S core, the base and the lid of the 19S cap, and the 11 S regulator. The ensuing chapter gives an overview of the structure and assembly of the 20S proteasome and the regulation of the archaeal proteasome by PAN. The third contribution summarizes our knowledge on the eukaryotic 26S proteasome and its regulation by the 19S regu lator, followed by a chapter devoted to the llS regulator, which elucidates the structural basis for the 11 S-mediated activation of the 20S proteasome. The fifth chapter reviews in detail the role of the proteasome in the immune response. The subsequent chapter of the natural substrates of the gives a comprehensive description proteasome and their recognition by the enzymes of the ubiqui tination machinery. The penultimate chapter rounds up the in formation on intracellular distribution of proteasomes in yeast and mammalian cells, while the last contribution highlights proteasome inhibitors, tools which proved to be very valuable for dissecting the cellular roles of the proteasome and which might turn out to be of pharmacological importance.