Ubiquitin-mediated regulation of endocytosis by proteins of the arrestin family

This is an open access article distributed under the Creative Commons Attribution License.-- et al.In metazoans, proteins of the arrestin family are key players of G-protein-coupled receptors (GPCRS) signaling and trafficking. Following stimulation, activated receptors are phosphorylated, thus allowing the binding of arrestins and hence an >arrest> of receptor signaling. Arrestins act by uncoupling receptors from G proteins and contribute to the recruitment of endocytic proteins, such as clathrin, to direct receptor trafficking into the endocytic pathway. Arrestins also serve as adaptor proteins by promoting the recruitment of ubiquitin ligases and participate in the agonist-induced ubiquitylation of receptors, known to have impact on their subcellular localization and stability. Recently, the arrestin family has expanded following the discovery of arrestin-related proteins in other eukaryotes such as yeasts or fungi. Surprisingly, most of these proteins are also involved in the ubiquitylation and endocytosis of plasma membrane proteins, thus suggesting that the role of arrestins as ubiquitin ligase adaptors is at the core of these proteins' functions. Importantly, arrestins are themselves ubiquitylated, and this modification is crucial for their function. In this paper, we discuss recent data on the intricate connections between arrestins and the ubiquitin pathway in the control of endocytosis.This work was supported by the CNRS and by a Grant from the Fondation ARC pour la recherche sur le cancer (SFI20101201844) to S. Léon, and by a Grant from the Spanish CICYT (BFU2008-02005) to O. Vincent. M. Becuwe and A. Herrador are recipients of Ph.D. fellowships from the French Ministère de l’Enseignement Supérieur et de la Recherche and from CSIC-JAE, respectively.Peer Reviewe

Análisis funcional de Rim8, una proteína de la familia de las arrestinas en Saccharomyces cerevisiae

Memoria que para optar al grado de Doctor por la Universidad Autónoma de Madrid presenta el Licenciado en Bioquímica Antonio Herrador Fernández, y realizada en el Instituto de Investigaciones Biomédicas “Alberto Sols” (CSIC-IIBM).[ES]: En las células de mamíferos, las β-arrestinas desempeñan la función clave de regular la endocitosis de los receptores de siete hélices transmembrana (7TM). Recientemente, la proteína PalF del hongo Aspergillus nidulans fue identificada como el primer miembro de la familia de las arrestinas fuera de los metazoos. PalF y Rim8, su homólogo en la levadura Saccharomyces cerevisiae, son componentes clave de la ruta de señalización de pH ambiental. En esta ruta denominada RIM en levadura, las proteínas 7TM, Rim21 y Dfg16, actúan corriente arriba de Rim8 y de la maquinaria endocítica ESCRT (del inglés “Endosomal Sorting Complex Required for Transport”). Ya que las β-arrestinas interaccionan con proteínas 7TM mediante sus dominios arrestina y con proteínas de la maquinaria endocítica mediante su región C-terminal, nos preguntamos si Rim8 podría llevar a cabo esta misma función en el contexto de la ruta RIM. En este trabajo demostramos que la región N-terminal de Rim8 interacciona de forma directa con la región C-terminal de la proteína 7TM Rim21. Asimismo, Rim8 interacciona de forma directa, mediante su región C-terminal, con la subunidad Vps23 del complejo ESCRT-I. De igual modo, demostramos que en extractos proteicos Rim8 está asociado a varias subunidades del complejo ESCRT-I y que esta asociación es fundamental para la transmisión de la señal de pH. Además, hemos caracterizado los determinantes moleculares que conjuntamente están involucrados en esta interacción: un motivo SXP y un residuo de lisina monoubicuitilado, ambos situados en el extremo C-terminal de Rim8 y altamente conservados. Por otro lado, demostramos que Rim8 es reconocido por la ubicuitina ligasa Rsp5 a través de un motivo PXY próximo al residuo ubicuitilado de Rim8. Esta ubicuitina ligasa monoubicuitila Rim8 porque la unión del dominio UEV (del inglés “ubiquitin E2 variant”) de Vps23 al motivo SXP y a la ubicuitina conjugada impide que se extienda la cadena de ubicuitina. Proponemos un modelo en el cual la competición entre Rsp5 y Vps23 por la unión a la primera molécula de ubicuitina conjugada con Rim8 es responsable de este fenómeno. Por último, demostramos que Rim8 se localiza en focos situados en la membrana plasmática de manera dependiente de la activación de la ruta RIM y que colocaliza con este mismo patrón con Rim21 y Vps23 cuando se co-sobreexpresa junto con estas proteínas.[EN]: Mammalian β-arrestins play a key role in the regulation of seven-transmembrane-spanning receptors (7TM) endocytosis. Recently, the fungal protein PalF from Aspergillus nidulans has been identified as the first non-metazoan member of the arrestin family. PalF and its homolog in the yeast Saccharomyces cerevisiae, Rim8, are key components of the ambient pH signalling pathway. In the yeast RIM pathway, 7TM proteins Rim21 and Dfg16, act upstream of both Rim8 and the ESCRT (“Endosomal Sorting Complex Required for Transport”) endocytic machinery. Because β-arrestins act as scaffold proteins which bind to both 7TM receptors and endocytic proteins through their arrestin domains and C-terminal region respectively, we wondered if Rim8 could mediate the connection between Rim21 and the ESCRT machinery in the RIM pathway. Here we show that the Rim8 N-terminal region interacts with the C-terminal tail of Rim21 and that Rim8 C-terminus binds directly to the ESCRT-I subunit Vps23. Furthermore, we show that Rim8 associates with ESCRT-I subunits in cellular extracts and that this interaction is essential for pH signal transduction. Moreover, we have identified the molecular determinants involved in Rim8 interaction with Vps23: an SXP motif and a ubiquitylated lysine residue, K521, both highly conserved and located within Rim8 C-terminus. We demonstrate, as well, that the E3 ubiquitin ligase Rsp5 recognizes a PXY motif located near the ubiquitylated residue in Rim8. Rsp5 monoubiquitylates Rim8 because the Vps23 UEV (ubiquitin E2 variant) domain binds to both the SXP motif and the first conjugated ubiquitin, thus blocking ubiquitin chain elongation. We propose a model in which the competition of Vps23 with Rsp5 for binding to the first conjugated ubiquitin is responsible for this mechanism. Finally, we show that Rim8 localizes to plasma membrane foci in an ambient pH-dependent manner and that it colocalizes with Rim21 and Vps23 when overexpressed together with these proteins.Peer Reviewe

Structural effects of steel reinforcement corrosion on statically indeterminate reinforced concrete members

The final publication is available at Springer via http://dx.doi.org/10.1617/s11527-016-0836-2Steel corrosion in reinforced concrete structures produces loss of reinforcement area and damage in the surrounding concrete. As a consequence, increases in deflections, crack widths and stresses may take place, as well as a reduction of the bearing capacity, which depends on the structural scheme and redundancy. In this paper an experimental study of twelve statically indeterminate beams subjected to different levels of forced reinforcement corrosion is presented. Different sustained loads were applied during the corrosion phase to assess their influence on the effects of corrosion. An important increase in deflections was registered in all corroded beams, especially in those subject to higher load levels. It was also found that the rate of corrosion was affected by the load level. Internal forces redistributions due to induced damage were measured. Finally, the experimental results were compared with those predicted by a non-linear time-dependent segmental analysis model developed by the authors, obtaining in general good agreement.Peer ReviewedPostprint (author's final draft

Análisis funcional de Rim8, una proteína de la familia de las arrestinas en Saccharomyces cerevisiae

Tesis doctoral inédita, leída en la Universidad Autónoma de Madrid, Facultad de Medicina, Departamento de Bioquímica. Fecha de lectura: 4 de Abril de 201

Geosintéticos en carreteras : planteamientos para su aplicación en las capas de firme

[Resumen:] Este artículo realiza un acercamiento general a la utilización actual de los geosintéticos en el diseño y construcción de carreteras. Una vez hecho ese acercamiento general se presentan planteamientos para la aplicación de este tipo de materiales en el diseño del firme de las carreteras en nuestro país. Finalmente se presentan las conclusiones y futuros desarrollos para avanzar en la utilización de esta tecnología en las capas de firme a nivel nacional.[Abstract:] This paper takes a general approach of geosynthetics in the design and roads construction current use. Afterward proposals for the implementation of these materials in the design of road surfaces in our country are presented. Finally, conclusions and future developments to advance the use of this technology in pavement layers nationwide are presented

Art as an attractive methodology of resilience and self-esteem

The objective of this research is to know the relationship between the level of self-esteem and resilience that people with intellectual disabilities have and the methodology of work including art. In this study, a mixed methodology has been used, the resilience indicator chosen in this research was the level of self-esteem. For the collection of data, a Likert scale and a semi-structured interview were used. The results show that there are significant differences between the self-esteem of people with intellectual disabilities that are influenced by methodologies that include art, concerning to other methodologies

A Practical Way to ISO/GUM Measurement Uncertainty for Analytical Assays Including In-House Validation Data

In this contribution, we outline the estimation of measurement uncertainty of analytical assays in a practical way, according to the so-called reconciliation paradigm, by considering the heritance of uncertainties according to the ISO Guide to the expression of uncertainty in measurement (ISO/GUM) approach and the accuracy (bias and precision) study coming from the in-house method validation. A cause and effect analysis is performed by using the Ishikawa diagram or fishbone plot, consisting of a hierarchical structure reaching a final outcome that is the analytical result. The procedure is illustrated with a case study. This procedure may be very suitable for processing data in accreditation of routine assays

Ultimate capacity of corroded statically indeterminate reinforced concrete members

The corrosion of steel reinforcement is commonly believed to be the primary cause of structural deterioration of reinforced concrete (RC) structures; as a result of this deterioration, a RC structure can incur a considerable reduction in structural serviceability and safety. Because of their inherent redundancy, statically indeterminate structures develop resistant mechanisms that can potentially assist in delaying the collapse of severely damaged RC structures. In order to experimentally demonstrate these resistant mechanisms, four groups of three two-span continuous RC beam members each were deteriorated using induced corrosion methods and tested to failure under monotonic loads. For control, one group of three RC beams was left uncorroded and similarly load tested. All the RC beam specimens subjected to corrosion demonstrated a significant reduction (a maximum reduction of 55% as compared to the uncorroded control group) of their ultimate capacity. The presence of corrosion induced a transition from flexural failure to anchorage failure in some specimens; despite the induced damage some redistributed structural capacity was observed. Modelling of deterioration effects by the inclusion of different aspects of corrosion was also conducted. Three-dimensional (3D) Finite-Element Method (FEM) models were developed to assess the variation in the mechanical properties of the corroded steel and the reduction in the bond interaction between concrete and steel due to the corrosion of the steel reinforcement. In general, the current 3D FEM models demonstrated a good agreement with the experimental data; however, 3D FEM models that exhibit greater sophistication are necessary to better describe the failure mode of some RC beam specimens when they are associated with local effects.Peer ReviewedPostprint (published version

A Minor Dihydropyran Apocarotenoid from Mated Cultures of Blakeslea trispora

The heterocyclic C15 apocarotenoid 1 was isolated from mated cultures of the strains F986 (+) and F921 (−) of Blakeslea trispora. This new compound formed during sexual interaction is a minor constituent of the culture media and its structure was elucidated by spectroscopic data, including 2D-NMR. A plausible biosynthetic pathway involving a double degradation of β-carotene, followed by several oxidations of the resulting monocyclofarnesane C15 fragment is proposed.This research was financed by Junta de Andalucía (Grants FQM 340, CVI 910, and P08-CVI-03901) and the Spanish Government (Grant CTQ 2010-16818, subprogram BQ)

Ansiedad entre cuidadores de pacientes con Enfermedad Pulmonar Obstructiva Crónica tras el alta hospitalaria

Objective: To identify the factors that influence changes in caregivers anxiety status three months after discharge for acute exacerbation of Chronic Obstructive Pulmonary Disease (COPD).Methodology: Longitudinal study. Participants included 87 caregivers of patients hospitalized for acute exacerbation of COPD. Anxiety was measured at the time of hospitalization and three months after discharge. We measured factors from four domains: context of care, caregiving demands, caregiver resources, and patient characteristics. We used multiple univariate and multivariate logistic regressions to determine changes in anxiety three months later. Univariate and multivariate multiple logistic regressions were used to determine changes in anxiety three months later.Results: A total of 57.5% of caregivers reported anxiety at the time of hospitalization. Of these, 44% had a remission of their anxiety three months after discharge. However, 22% of caregivers who had not experienced anxiety at the hospitalization became anxious at 3 months. The severity of COPD and not receiving help from another caregiver decreased the likelihood of remission of anxiety. Moderately high overload increases the likelihood of experiencing anxiety symptoms.Conclusions: The perception of anxious symptoms is dynamic. Caregivers are likely to recover from anxiety when they receive help from another caregiver and if the patient they are caring for does not have severe COPD.Objetivo: Identificar los factores que influyen en cambios en la ansiedad de los cuidadores tres meses después del alta hospitalaria por exacerbación aguda de la Enfermedad Pulmonar Obstructiva Crónica (EPOC).  Metodología: Estudio longitudinal. Participaron 87 cuidadores de pacientes hospitalizados por exacerbación aguda de EPOC. Se midió la ansiedad en el momento de la hospitalización y tres meses después del alta. Además, se midieron potenciales factores asociados a su cambio en cuatro dominios: Contexto del cuidado, demandas del cuidado, recursos y características del paciente. Utilizamos regresiones logísticas múltiples univariadas y multivariadas para determinar los cambios en la ansiedad tres meses después. Resultados: Presentaron ansiedad en el momento de la hospitalización el 57,5% de los cuidadores. De ellos, el 44% había remitido su ansiedad tres meses después del alta hospitalaria. Sin embargo, el 22% de los cuidadores quienes no habían presentado ansiedad en el momento de la hospitalización se mostraron ansiosos a los 3 meses. La gravedad de la EPOC y no recibir apoyo de otro cuidador disminuyó las probabilidades de remisión de la ansiedad. La sobrecarga moderadamente alta incrementa las probabilidades de presentar  nuevos síntomas de ansiedad. Conclusiones: La percepción de los síntomas de la ansiedad es dinámica. Los cuidadores pueden recuperarse si reciben ayuda de otro cuidador o si el paciente al que cuidan no está en un estado severo de EPOC