The ubiquitin conjugase Rad6 mediates ribosome pausing during oxidative stress.

Oxidative stress causes K63-linked ubiquitination of ribosomes by the E2 ubiquitin conjugase Rad6. How Rad6-mediated ubiquitination of ribosomes affects translation, however, is unclear. We therefore perform Ribo-seq and Disome-seq in Saccharomyces cerevisiae and show that oxidative stress causes ribosome pausing at specific amino acid motifs, which also leads to ribosome collisions. However, these redox-pausing signatures are lost in the absence of Rad6 and do not depend on the ribosome-associated quality control (RQC) pathway. We also show that Rad6 is needed to inhibit overall translation in response to oxidative stress and that its deletion leads to increased expression of antioxidant genes. Finally, we observe that the lack of Rad6 leads to changes during translation that affect activation of the integrated stress response (ISR) pathway. Our results provide a high-resolution picture of the gene expression changes during oxidative stress and unravel an additional stress response pathway affecting translation elongation.

Redox-sensitive E2 Rad6 controls cellular response to oxidative stress via K63-linked ubiquitination of ribosomes.

Protein ubiquitination is an essential process that rapidly regulates protein synthesis, function, and fate in dynamic environments. Within its non-proteolytic functions, we showed that K63-linked polyubiquitinated conjugates heavily accumulate in yeast cells exposed to oxidative stress, stalling ribosomes at elongation. K63-ubiquitinated conjugates accumulate mostly because of redox inhibition of the deubiquitinating enzyme Ubp2; however, the role and regulation of ubiquitin-conjugating enzymes (E2) in this pathway remained unclear. Here, we show that the E2 Rad6 associates and modifies ribosomes during stress. We further demonstrate that Rad6 and its human homolog UBE2A are redox regulated by forming a reversible disulfide with the E1 ubiquitin-activating enzyme (Uba1). This redox regulation is part of a negative feedback regulation, which controls the levels of K63 ubiquitination under stress. Finally, we show that Rad6 activity is necessary to regulate translation, antioxidant defense, and adaptation to stress, thus providing an additional physiological role for this multifunctional enzyme.

Mulheres privadas de liberdade e seus filhos: o sistema de justiça criminal em perspectiva / Female inmates and their children: criminal judicial system in perspective / Mujeres en privación de libertad y sus hijos: el sistema de justicia criminal en perspectiva

O texto surge de informações obtidas em uma pesquisa intitulada "Laços sociais de crianças após o cárcere" e se desenvolve percorrendo o sistema de justiça criminal do Brasil e de Minas Gerais, com reflexões psicanalíticas em interlocução com a perspectiva da sociologia jurídico-penal. Centra-se numa das fontes geradoras de conhecimentos utilizadas na pesquisa, o trabalho de juízes em processos que envolvem mulheres privadas de liberdade cujos filhos permanecem reclusos com elas por algum tempo. Traz declarações de juízes acerca de pontos cruciais sobre o assunto, nas quais se observa que os atores do sistema de justiça circulam pela administração ordinária da justiça penal, regida pelo princípio da eficiência, por competência voltada para o exato cumprimento da lei, e ainda distante das particularidades que supõem a diferença entre os sexos, a garantia dos direitos fundamentais da criança, numa realidade social que prima pela complexa judicialização da relação entre mãe e filho.

The idea to write this text came from information acquired during a research entitled "Social bonds of children after prison", which was done studying the criminal justice system of Brazil and Minas Gerais. The research has psychoanalytic reflections in interlocution with the perspective of legal-penal sociology. The work of judges in cases involving women sentenced to prison and their children, who have lived with their mothers some time, is the focus of this research. It contains judges' statements related to crucial points in the subject, in which the actors of the judicial system can be observed. Those statements spread through the ordinary administration of criminal justice, governed by the principle of efficiency and by competence directed towards strict law enforcement. However, these procedures are still far from the particulars that gender differences and the guarantee of the child's fundamental rights entail, in a social reality mainly represented by the complex judicialisation of the relation between mother and child.

El texto surge a partir de informaciones obtenidas en una investigación titulada "Lazos sociales de niños tras la cárcel", y se desarrolla recorriendo el sistema de justicia criminal de Brasil y de Minas Gerais y con reflexiones psicoanalíticas en interlocución con la perspectiva de la sociología jurídico-penal. Se centra en una de las fuentes generadoras de conocimientos utilizadas en la investigación, el trabajo de los jueces en los procesos en que están envolvidas mujeres privadas de libertad y sus hijos que permanecen recluidos con ellas durante algún tiempo. Se citan declaraciones de jueces sobre los puntos cruciales de este tema en las que se observa que los actores del sistema de justicia se difunden por la administración ordinaria de la justicia penal regida por el principio de eficiencia, por la competencia orientada al exacto cumplimiento de la ley, y todavía distante de las particularidades que supone la diferencia de sexos y la garantía de los derechos fundamentales del niño en una realidad social en la que prevalece la compleja judicialización de la relación entre madre e hijo.

Polyubiquitin Chains Linked by Lysine Residue 48 (K48) Selectively Target Oxidized Proteins In Vivo.

Aims: Ubiquitin is a highly conserved protein modifier that heavily accumulates during the oxidative stress response. Here, we investigated the role of the ubiquitination system, particularly at the linkage level, in the degradation of oxidized proteins. The function of ubiquitin in the removal of oxidized proteins remains elusive because of the wide range of potential targets and different roles that polyubiquitin chains play. Therefore, we describe in detail the dynamics of the K48 ubiquitin response as the canonical signal for protein degradation. We identified ubiquitin targets and defined the relationship between protein ubiquitination and oxidation during the stress response. Results: Combining oxidized protein isolation, linkage-specific ubiquitination screens, and quantitative proteomics, we found that K48 ubiquitin accumulated at both the early and late phases of the stress response. We further showed that a fraction of oxidized proteins are conjugated with K48 ubiquitin. We identified ∼750 ubiquitinated proteins and ∼400 oxidized proteins that were modified during oxidative stress, and around half of which contain both modifications. These proteins were highly abundant and function in translation and energy metabolism. Innovation and Conclusion: Our work showed for the first time that K48 ubiquitin modifies a large fraction of oxidized proteins, demonstrating that oxidized proteins can be targeted by the ubiquitin/proteasome system. We suggest that oxidized proteins that rapidly accumulate during stress are subsequently ubiquitinated and degraded during the late phase of the response. This delay between oxidation and ubiquitination may be necessary for reprogramming protein dynamics, restoring proteostasis, and resuming cell growth.

Cross-talk between redox regulation and the ubiquitin-proteasome system in mammalian cell differentiation.

BACKGROUND: Embryogenesis and stem cell differentiation are complex and orchestrated signaling processes. Reactive oxygen species (ROS) act as essential signal transducers in cellular differentiation, as has been shown through recent discoveries. On the other hand, the ubiquitin-proteasome system (UPS) has long been known to play an important role in all cellular regulated processes, including differentiation. SCOPE OF REVIEW: In the present review, we focus on findings that highlight the interplay between redox signaling and the UPS regarding cell differentiation. Through systems biology analyses, we highlight major routes during cardiomyocyte differentiation based on redox signaling and UPS modulation. MAJOR CONCLUSION: Oxygen availability and redox signaling are fundamental regulators of cell fate upon differentiation. The UPS plays an important role in the maintenance of pluripotency and the triggering of differentiation. GENERAL SIGNIFICANCE: Cellular differentiation has been a matter of intense investigation mainly because of its potential therapeutic applications. Understanding regulatory mechanisms underlying cell differentiation is an important issue. Correspondingly, the role of UPS and regulation of redox processes have been emerged as essential factors to control the fate of cells upon differentiation. This article is part of a Special Issue entitled Redox regulation of differentiation and de-differentiation.

A terapia da realidade virtual e a pessoa queimada: redução da dor nos cuidados à ferida - Uma revisão integrativa da literatura / Virtual reality therapy and the burn patient: reduction of pain in the wound care - A integrative literature review

Introdução: Terapias farmacológicas não têm conseguido um controle efetivo da dor na pessoa queimada nas três dimensões da dor aquando os cuidados à ferida. Assim, a Terapia da Realidade Virtual (TRV) baseia-se numa abordagem tecnológica que isola a pessoa do mundo real, visualizando apenas um ambiente virtual. Objetivo: Nesta Revisão Integrativa da Literatura pretende-se: identificar se a aplicação da TRV reduz a dor nas três dimensões aquando os cuidados à ferida; verificar em que medida a aplicação da TRV reduz a dor em cada uma das três dimensões de dor; verificar se a aplicação da TRV permite a redução de administração da analgesia opioide. Método: Efetuou-se pesquisa em motores de busca online, num período temporal de dez anos por meio de descritores e critérios de inclusão predefinidos. Definiu-se como questão de investigação "Qual é a eficácia da aplicação da Terapia da Realidade Virtual na redução da dor nos cuidados à ferida à pessoa numa unidade de queimados?". Na consecução deste trabalho, teve-se como método os Sete Passos do Cochrane Handbook, sendo incluídos seis artigos. Resultados: Pela análise dos resultados, evidencia-se a redução da dor nas três dimensões, na maioria dos estudos, quando associada a TRV a terapias farmacológicas. Conclusões: Propõem-se mais estudos randomizados controlados para definir os benefícios da TRV, comparativamente com terapias não farmacológicas menos dispendiosas.

Introduction: Pharmacological therapy have failed to effective pain management caused by burns, in the three dimensions of pain at the wound care. So, Virtual Reality Therapy (VRT) there is a non pharmacological successful alternative that isolates the patient from the real world and allows them to experience only a virtual tridimensional environment. Objective: With this Integrative Revision of the Literature we intend in the context of the wound care in burn units: realize if the application of the VRT reduces the level of pain dimensions; verify how VRT lowers the level of each dimension of pain; verify if VRT allows a reduction of the dose of opioid analgesics needed to control the pain. Method: To do our research we used information from online search engines from the past ten years through descriptors and predefined inclusion criteria. In order to find answers to our main goals we came up with the following question: What is the efficacy of the application of the VRT in reducing the pain caused by the treatment of the burns in a Burn Unit? In pursuing this work had as the Seven Steps method of the Cochrane Handbook, which included 6 articles. Results: For the analysis of the results shows the reduction of the dimensions of pain in most studies when combined with TRV to pharmacological therapies. Conclusions: Propose is more randomized controlled trials to determine the benefits of TRV, compared with less costly non-pharmacological therapies.

Redox control of 20S proteasome gating.

UNLABELLED: The proteasome is the primary contributor in intracellular proteolysis. Oxidized or unstructured proteins can be degraded via a ubiquitin- and ATP-independent process by the free 20S proteasome (20SPT). The mechanism by which these proteins enter the catalytic chamber is not understood thus far, although the 20SPT gating conformation is considered to be an important barrier to allowing proteins free entrance. We have previously shown that S-glutathiolation of the 20SPT is a post-translational modification affecting the proteasomal activities. AIMS: The goal of this work was to investigate the mechanism that regulates 20SPT activity, which includes the identification of the Cys residues prone to S-glutathiolation. RESULTS: Modulation of 20SPT activity by proteasome gating is at least partially due to the S-glutathiolation of specific Cys residues. The gate was open when the 20SPT was S-glutathiolated, whereas following treatment with high concentrations of dithiothreitol, the gate was closed. S-glutathiolated 20SPT was more effective at degrading both oxidized and partially unfolded proteins than its reduced form. Only 2 out of 28 Cys were observed to be S-glutathiolated in the proteasomal α5 subunit of yeast cells grown to the stationary phase in glucose-containing medium. INNOVATION: We demonstrate a redox post-translational regulatory mechanism controlling 20SPT activity. CONCLUSION: S-glutathiolation is a post-translational modification that triggers gate opening and thereby activates the proteolytic activities of free 20SPT. This process appears to be an important regulatory mechanism to intensify the removal of oxidized or unstructured proteins in stressful situations by a process independent of ubiquitination and ATP consumption. Antioxid. Redox Signal. 16, 1183-1194.