Focus on Ubiquitin

Essential modifications - p289

doi:10.1038/nsmb.2811

Ubiquitin and ubiquitin-like proteins have central roles in regulating cellular processes and homeostasis. This Focus examines our understanding of the ubiquitination reaction and the mechanisms by which ubiquitin and related modifications affect protein and cellular functions.

Full Text - Essential modifications | PDF (346 KB) - Essential modifications

Focus on Ubiquitin

Ubiquitin sets the timer: impacts on aging and longevity - pp290 - 292

Éva Kevei & Thorsten Hoppe

doi:10.1038/nsmb.2806

Protein homeostasis is essential for cellular function, organismal growth and viability. Damaged and aggregated proteins are turned over by two major proteolytic routes of the cellular quality-control pathways: the ubiquitin-proteasome system and autophagy. For both these pathways, ubiquitination provides the recognition signal for substrate selection. This Commentary discusses how ubiquitin-dependent proteolytic pathways are coordinated with stress- and aging-induced signals.

Full Text - Ubiquitin sets the timer: impacts on aging and longevity | PDF (592 KB) - Ubiquitin sets the timer: impacts on aging and longevity

Focus on Ubiquitin

Plant ubiquitin ligases as signaling hubs - pp293 - 296

Nitzan Shabek & Ning Zheng

doi:10.1038/nsmb.2804

The past decade has witnessed an explosion in the identification of ubiquitin-ligase complexes as the missing receptors for important small-molecule hormones regulating plant growth and development. These breakthroughs were initiated by genetic approaches, with structural analysis providing mechanistic insights into how hormone perception and signaling are coupled to protein ubiquitination. Although there are still many unknowns, plants have imparted valuable lessons about the pharmacology of ubiquitin modification.

Full Text - Plant ubiquitin ligases as signaling hubs | PDF (771 KB) - Plant ubiquitin ligases as signaling hubs

Focus on Ubiquitin

Ubiquitin in inflammation: the right linkage makes all the difference - pp297 - 300

Jacob E Corn & Domagoj Vucic

doi:10.1038/nsmb.2808

The immune system must operate in an effective, precise and safe manner to defend against diverse pathogens while avoiding attacking the body itself and commensal bacteria. Inflammatory pathways mediated by NOD-like, Toll-like, RIG-I–like and tumor-necrosis-factor receptor families are tightly regulated by ubiquitination, especially by Lys63-linked and linear polyubiquitin chains. Here we discuss the human ubiquitin-mediated inflammatory signaling system, emphasizing the interactions and activities whose coordination ensures timely, accurate regulation of inflammatory responses.

Full Text - Ubiquitin in inflammation: the right linkage makes all the difference | PDF (1,526 KB) - Ubiquitin in inflammation: the right linkage makes all the difference

Focus on Ubiquitin

New insights into ubiquitin E3 ligase mechanism - pp301 - 307

Christopher E Berndsen & Cynthia Wolberger

doi:10.1038/nsmb.2780

Ubiquitin E3 ligases catalyze the final step of the ubiquitination cascade, promoting the transfer of ubiquitin from the E2 to the substrate target. Recent structural and biochemical studies have given insights in the catalytic mechanisms of all three E3 ligase classes, discussed in this Review.

Abstract - New insights into ubiquitin E3 ligase mechanism | Full Text - New insights into ubiquitin E3 ligase mechanism | PDF (1,362 KB) - New insights into ubiquitin E3 ligase mechanism

Focus on Ubiquitin

Lysine-targeting specificity in ubiquitin and ubiquitin-like modification pathways - pp308 - 316

Francesca Mattiroli & Titia K Sixma

doi:10.1038/nsmb.2792

Ubiquitin (Ub) and ubiquitin-like (Ubl) modifications occur primarily on lysine residues of target proteins to stimulate downstream signals. This Review discusses our current knowledge of lysine specificity in Ub and Ubl targeting, with particular focus on the systems where a detailed mechanism of modification and downstream signaling has been validated biochemically.

Abstract - Lysine-targeting specificity in ubiquitin and ubiquitin-like modification pathways | Full Text - Lysine-targeting specificity in ubiquitin and ubiquitin-like modification pathways | PDF (1,097 KB) - Lysine-targeting specificity in ubiquitin and ubiquitin-like modification pathways

Focus on Ubiquitin

Two-way communications between ubiquitin-like modifiers and DNA - pp317 - 324

Helle D Ulrich

doi:10.1038/nsmb.2805

DNA metabolism is regulated by the ubiquitin and SUMO modifications, but DNA also influences whether and when these modifications occur. This Review describes the mutual interactions between DNA, ubiquitin and SUMO that occur in DNA-associated processes.

Abstract - Two-way communications between ubiquitin-like modifiers and DNA | Full Text - Two-way communications between ubiquitin-like modifiers and DNA | PDF (799 KB) - Two-way communications between ubiquitin-like modifiers and DNA

Focus on Ubiquitin

Cleaning up in the endoplasmic reticulum: ubiquitin in charge - pp325 - 335

John C Christianson & Yihong Ye

doi:10.1038/nsmb.2793

The ER-associated degradation (ERAD) pathway maintains protein homeostasis in the ER by retrotranslocating unwanted proteins to the cytosol for proteasomal degradation. This Review discusses the integral role of the ubiquitin system in ERAD, highlighting how the two pathways intertwine to facilitate transport across the ER membrane.

Abstract - Cleaning up in the endoplasmic reticulum: ubiquitin in charge | Full Text - Cleaning up in the endoplasmic reticulum: ubiquitin in charge | PDF (971 KB) - Cleaning up in the endoplasmic reticulum: ubiquitin in charge

Focus on Ubiquitin

Dynamic regulation of macroautophagy by distinctive ubiquitin-like proteins - pp336 - 345

Daniel J Klionsky & Brenda A Schulman

doi:10.1038/nsmb.2787

Whereas the proteasome degrades individual proteins modified with ubiquitin chains, autophagy degrades many proteins and organelles en masse. A pair of ubiquitin-like proteins, Atg8 and Atg12, regulate autophagy-mediated degradation in a manner completely distinct from that of ubiquitin in the proteasome pathway, as discussed in this Review.

Abstract - Dynamic regulation of macroautophagy by distinctive ubiquitin-like proteins | Full Text - Dynamic regulation of macroautophagy by distinctive ubiquitin-like proteins | PDF (14,370 KB) - Dynamic regulation of macroautophagy by distinctive ubiquitin-like proteins