El combatir el terror de estado y la evolución hacía un estado: El movimiento de los Derechos Humanos de Argentina, desde la movilización a la institucionalización

The past decade has seen a seismic shift in Argentine human rights activists’ ability to accomplish long-held goals of bringing perpetrators to justice and preserving the memory of victims of the Civil-State dictatorship of the 1970s and 1980s. Theories of courageous resistance to injustice posit that all struggles for justice bring changes to the context, networks and people, which can make future pro-social advocacy more likely. Using a variety of evidence, we assess the impact of nearly 40 years of sustained activism. We argue that there are resulting shifts in the realms of 1) context (newly created and modified legal and state institutions, cultural changes and modification of the physical landscape), 2) relationships between activists, society and the Argentine state, and 3) socialization factors that affect attitudes and behaviors of Argentines (the ways that the era is referenced, taught and memorialized). We contend that each of these enduring legacies of activism make future human rights atrocities in Argentina highly unlikely. Further, we argue that because of these enormous gains, segments of the movement struggle to define themselves relative to the state, trying to avoid being captured by governmental interests and to maintain sufficient independence to effectively pressure the state.La década pasada ha visto un cambio sísmico en la habilidad de activistas argentinos por los derechos humanos de realizar metas largamente sostenidas, como las de llevar ante la justicia a los perpetradores y preservar la memoria de las víctimas de dictadura civil-estatal de los años setenta y ochenta. Las teorías de courageous resistance a la injusticia postulan que toda lucha por justicia produce cambios en el contexto, las redes y las personas, los cuales pueden mejorar la probabilidad de incidencia política prosocial para el futuro. En base a una variedad de evidencia, evaluamos el impacto de casi 40 años de activismo sostenido. Argumentamos que hay cambios resultantes en las esferas de 1) el contexto (instituciones legales y estatales nuevamente creadas y modificadas, cambios culturales y modificaciones al paisaje físico), 2) las relaciones entre activistas, la sociedad y el Estado argentino y 3) factores en la socialización que afectan las actitudes y el comportamiento de argentinos (cambios en las formas de referenciar, enseñar y conmemorar la época). Sostenemos que cada uno de estos importantes y duraderos legados de activismo hace que futuras atrocidades de derechos humanos en la Argentina sean altamente improbables. Además, argumentamos que, a causa de estos logros, sectores del movimiento se definen difícilmente con respecto al Estado, intentando evitar la captura por los intereses gubernamentales y mantener una independencia suficiente para presionar eficazmente al Estado

Direct multiplexing of low order aberration modes in a photopolymerbased holographic element for analog holographic wavefront sensing

The fabrication of an analog holographic wavefront sensor, capable of detecting the low order defocus aberration, was achieved in an acrylamide-based photopolymer. While other implementations of holographic wavefront sensors have been carried out digitally, this process utilises a recording setup consisting only of conventional refractive elements so the cost and complexity of holographic optical element (HOE) production could be much reduced. A pair of diffraction spots, corresponding to a maximum and minimum amount of defocus, were spatially separated in the detector plane by multiplexing two HOEs with different carrier spatial frequencies. For each wavefront with a known aberration that was introduced during playback of the hologram, the resulting intensity ratio was measured in the expected pair of diffracted spots. A number of HOEs were produced with the diffraction efficiency of the multiplexed elements equalized, for a range of diffraction efficiency strengths, some as low as \u3c5%. These HOEs were used to successfully classify four amounts of the defocus aberration through the observed intensity ratio

Analog holographic wavefront sensor for defocus and spherical aberration measurement recorded in a photopolymer

An analog holographic wavefront sensor (AHWFS), for measurement of low and high order (defocus and spherical aberration) aberration modes has been developed as volume phase holograms in a photopolymer recording medium. This is the first time that high order aberrations such as spherical aberration can be sensed using a volume hologram in a photosensitive medium. Both defocus and spherical aberration were recorded in a multi-mode version of this AHWFS. Refractive elements were used to generate a maximum and minimum phase delay of each aberration which were multiplexed as a set of volume phase holograms in an acrylamide based-photopolymer layer. The single-mode sensors showed a high degree of accuracy in determining various magnitudes of defocus and spherical aberration generated refractively. The multi-mode sensor also exhibited promising measurement characteristics and similar trends to the single-mode sensors were observed. The method of quantifying defocus was improved upon and a brief study into material shrinkage and sensor linearity is presented

Modelling spherical aberration detection in an analog holographic wavefront sensor

The analog holographic wavefront sensor (AHWFS) is a simple and robust solution to wavefront sensing in turbulent environments. Here, the ability of a photopolymer based AHWFS to detect refractively generated spherical aberration is modelled and verified

Photocrosslinking Activity-Based Probes for Ubiquitin RING E3 Ligases

Summary: Activity-based protein profiling is an invaluable technique for studying enzyme biology and facilitating the development of therapeutics. Ubiquitin E3 ligases (E3s) are one of the largest enzyme families and regulate a host of (patho)physiological processes. The largest subtype are the RING E3s of which there are >600 members. RING E3s have adaptor-like activity that can be subject to diverse regulatory mechanisms and have become attractive drug targets. Activity-based probes (ABPs) for measuring RING E3 activity do not exist. Here we re-engineer ubiquitin-charged E2 conjugating enzymes to produce photocrosslinking ABPs. We demonstrate activity-dependent profiling of two divergent cancer-associated RING E3s, RNF4 and c-Cbl, in response to their native activation signals. We also demonstrate profiling of endogenous RING E3 ligase activation in response to epidermal growth factor (EGF) stimulation. These photocrosslinking ABPs should advance E3 ligase research and the development of selective modulators against this important class of enzymes

Identification of SUMO Targets Associated with the Pluripotent State in Human Stem Cells

To investigate the role of SUMO modification in the maintenance of pluripotent stem cells, we used ML792, a potent and selective inhibitor of SUMO Activating Enzyme. Treatment of human induced pluripotent stem cells with ML792 resulted in the loss of key pluripotency markers. To identify putative effector proteins and establish sites of SUMO modification, cells were engineered to stably express either SUMO1 or SUMO2 with C-terminal TGG to KGG mutations that facilitate GlyGly-K peptide immunoprecipitation and identification. A total of 976 SUMO sites were identified in 427 proteins. STRING enrichment created three networks of proteins with functions in regulation of gene expression, ribosome biogenesis, and RNA splicing, although the latter two categories represented only 5% of the total GGK peptide intensity. The rest have roles in transcription and the regulation of chromatin structure. Many of the most heavily SUMOylated proteins form a network of zinc-finger transcription factors centered on TRIM28 and associated with silencing of retroviral elements. At the level of whole proteins, there was only limited evidence for SUMO paralogue-specific modification, although at the site level there appears to be a preference for SUMO2 modification over SUMO1 in acidic domains. We show that SUMO influences the pluripotent state in hiPSCs and identify many chromatin-associated proteins as bona fide SUMO substrates in human induced pluripotent stem cells.</p

Key Binding Interactions for Memantine in the NMDA Receptor

Memantine (Namenda) is prescribed as a treatment for moderate to severe Alzheimer’s Disease. Memantine functions by blocking the NMDA receptor, but the key binding interactions between drug and receptor are not fully elucidated. To determine key binding interactions of memantine, we made side-by-side comparisons of IC_(50) for memantine and amantadine, a structurally related drug, in the GluN1/GluN2B NMDA receptor. We identified hydrophobic binding pockets for the two methyl groups on memantine formed by the residues A645 and A644 on the third transmembrane helices of GluN1 and GluN2B, respectively. Moreover, we found that while adding two methyl groups to amantadine to produce memantine greatly improves affinity, adding a third methyl group to produce the symmetrical trimethylamantadine diminished affinity. Our results provide a better understanding of chemical-scale interactions between memantine and the NMDA channel, which will potentially benefit the development of new drugs for neurodegenerative diseases involving NMDA receptors

RNF12 X-linked intellectual disability mutations disrupt E3 ligase activity and neural differentiation

Summary: X-linked intellectual disability (XLID) is a heterogeneous syndrome affecting mainly males. Human genetics has identified >100 XLID genes, although the molecular and developmental mechanisms underpinning this disorder remain unclear. Here, we employ an embryonic stem cell model to explore developmental functions of a recently identified XLID gene, the RNF12/RLIM E3 ubiquitin ligase. We show that RNF12 catalytic activity is required for proper stem cell maintenance and neural differentiation, and this is disrupted by patient-associated XLID mutation. We further demonstrate that RNF12 XLID mutations specifically impair ubiquitylation of developmentally relevant substrates. XLID mutants disrupt distinct RNF12 functional modules by either inactivating the catalytic RING domain or interfering with a distal regulatory region required for efficient ubiquitin transfer. Our data thereby uncover a key function for RNF12 E3 ubiquitin ligase activity in stem cell and neural development and identify mechanisms by which this is disrupted in intellectual disability. : Bustos et al. show that the RNF12 E3 ubiquitin ligase regulates stem cell maintenance and neuronal differentiation. They demonstrate that RNF12/RLIM mutations identified in X-linked intellectual disability patients disrupt regions required for catalytic activity, which leads to compromised stem cell maintenance and abnormal neural differentiation. Keywords: ubiquitin, protein ubiquitylation, E3 ubiquitin ligase, proteasomal degradation, RNF12/RLIM, intellectual disability, X-linked intellectual disability, embryonic stem cells, neural differentiatio

Engineering Thermostability in Artificial Metalloenzymes to Increase Catalytic Activity

Protein engineering has shown widespread use in improving the industrial application of enzymes and broadening the conditions they are able to operate under by increasing their thermostability and solvent tolerance. Here, we show that protein engineering can be used to increase the thermostability of an artificial metalloenzyme. Thermostable variants of the human steroid carrier protein 2L, modified to bind a metal catalyst, were created by rational design using structural data and a 3DM database. These variants were tested to identify mutations that enhanced the stability of the protein scaffold, and a significant increase in melting temperature was observed with a number of modified metalloenzymes. The ability to withstand higher reaction temperatures resulted in an increased activity in the hydroformylation of 1-octene, with more than fivefold improvement in turnover number, whereas the selectivity for linear aldehyde remained high up to 80%

Structural basis for the RING catalyzed synthesis of K63 linked ubiquitin chains

This work was supported by grants from Cancer Research UK (C434/A13067), the Wellcome Trust (098391/Z/12/Z) and Biotechnology and Biological Sciences Research Council (BB/J016004/1).The RING E3 ligase catalysed formation of lysine 63 linked ubiquitin chains by the Ube2V2–Ubc13 E2 complex is required for many important biological processes. Here we report the structure of the RING domain dimer of rat RNF4 in complex with a human Ubc13~Ub conjugate and Ube2V2. The structure has captured Ube2V2 bound to the acceptor (priming) ubiquitin with Lys63 in a position that could lead to attack on the linkage between the donor (second) ubiquitin and Ubc13 that is held in the active “folded back” conformation by the RING domain of RNF4. The interfaces identified in the structure were verified by in vitro ubiquitination assays of site directed mutants. This represents the first view of the synthesis of Lys63 linked ubiquitin chains in which both substrate ubiquitin and ubiquitin-loaded E2 are juxtaposed to allow E3 ligase mediated catalysis.PostprintPeer reviewe