SUMOylation regulates LKB1 localization and its oncogenic activity in liver cancer

BACKGROUND: Even though liver kinase B1 (LKB1) is usually described as a tumor suppressor in a wide variety of tissues, it has been shown that LKB1 aberrant expression is associated with bad prognosis in Hepatocellular Carcinoma (HCC). METHODS: Herein we have overexpressed LKB1 in human hepatoma cells and by using histidine pull-down assay we have investigated the role of the hypoxia-related post-translational modification of Small Ubiquitin-related Modifier (SUMO)ylation in the regulation of LKB1 oncogenic role. Molecular modelling between LKB1 and its interactors, involved in regulation of LKB1 nucleocytoplasmic shuttling and LKB1 activity, was performed. Finally, high affinity SUMO binding entities-based technology were used to validate our findings in a pre-clinical mouse model and in clinical HCC. FINDINGS: We found that in human hepatoma cells under hypoxic stress, LKB1 overexpression increases cell viability and aggressiveness in association with changes in LKB1 cellular localization. Moreover, by using site-directed mutagenesis, we have shown that LKB1 is SUMOylated by SUMO-2 at Lys178 hampering LKB1 nucleocytoplasmic shuttling and fueling hepatoma cell growth. Molecular modelling of SUMO modified LKB1 further confirmed steric impedance between SUMOylated LKB1 and the STe20-Related ADaptor cofactor (STRADα), involved in LKB1 export from the nucleus. Finally, we provide evidence that endogenous LKB1 is modified by SUMO in pre-clinical mouse models of HCC and clinical HCC, where LKB1 SUMOylation is higher in fast growing tumors. INTERPRETATION: Overall, SUMO-2 modification of LKB1 at Lys178 mediates LKB1 cellular localization and its oncogenic role in liver cancer. FUND: This work was supported by grants from NIH (US Department of Health and Human services)-R01AR001576-11A1 (J.M.M and M.L.M-C.), Gobierno Vasco-Departamento de Salud 2013111114 (to M.L.M.-C), ELKARTEK 2016, Departamento de Industria del Gobierno Vasco (to M.L.M.-C), MINECO: SAF2017-87301-R and SAF2014-52097-R integrado en el Plan Estatal de Investigación Cientifica y Técnica y Innovación 2013-2016 cofinanciado con Fondos FEDER (to M.L.M.-C and J.M.M., respectively), BFU2015-71017/BMC MINECO/FEDER, EU (to A.D.Q. and I.D.M.), BIOEF (Basque Foundation for Innovation and Health Research): EITB Maratoia BIO15/CA/014; Instituto de Salud Carlos III:PIE14/00031, integrado en el Plan Estatal de Investigación Cientifica y Técnica y Innovacion 2013-2016 cofinanciado con Fondos FEDER (to M.L.M.-C and J.M.M), Asociación Española contra el Cáncer (T.C.D, P·F-T and M.L.M-C), Daniel Alagille award from EASL (to T.C.D), Fundación Científica de la Asociación Española Contra el Cancer (AECC Scientific Foundation) Rare Tumor Calls 2017 (to M.L.M and M.A), La Caixa Foundation Program (to M.L.M), Programma di Ricerca Regione-Università 2007-2009 and 2011-2012, Regione Emilia-Romagna (to E.V.), Ramón Areces Foundation and the Andalusian Government (BIO-198) (A.D.Q. and I.D.M.), ayudas para apoyar grupos de investigación del sistema Universitario Vasco IT971-16 (P.A.), MINECO:SAF2015-64352-R (P.A.), Institut National du Cancer, FRANCE, INCa grant PLBIO16-251 (M.S.R.), MINECO - BFU2016-76872-R to (E.B.). Work produced with the support of a 2017 Leonardo Grant for Researchers and Cultural Creators, BBVA Foundation (M.V-R). Finally, Ciberehd_ISCIII_MINECO is funded by the Instituto de Salud Carlos III. We thank MINECO for the Severo Ochoa Excellence Accreditation to CIC bioGUNE (SEV-2016-0644). Funding sources had no involvement in study design; in the collection, analysis, and interpretation of data; in the writing of the report; and in the decision to submit the paper for publication

Dimerization model of the C-terminal RNA Recognition Motif of HuR

In PressHuman antigen R (HuR) is a ubiquitous 32kDa protein comprising three RNA Recognition Motifs (RRMs), whose main function is to bind Adenylate and uridylate Rich Elements (AREs) in 3′ UnTranslated Regions (UTRs) of mRNAs. In addition to binding RNA molecules, the third domain (RRM3) is involved in HuR oligomerization and apoptotic signaling. The RRM3 monomer is able to dimerize, with its self-binding affinity being dependent on ionic strength. Here we provide a deeper structural insight into the nature of the encounter complexes leading to the formation of RRM3 dimers by using Brownian Dynamics and Molecular Dynamics. Our computational data show that the initial unspecific encounter follows a downhill pathway until reaching an optimum conformation stabilized by hydrophobic interactions.I.D.-M. wishes to thank the Andalusian Government (P07-CVI-02896, P11-CVI-07216 and BIO198) for financial support.Peer reviewe

Fractura de piso orbitario en un jugador de béisbol

Presentamos un caso de un paciente, jugador de béisbol que sufrió una fractura de piso orbitario al recibir un golpe directo (blowout) con un bate que se le escapó a otro jugador, esta fractura fue reparada con un bloque de Hidroxiapatita Porosa HAP -200 .Una vez reconstruido el defecto óseo, el paciente volvió a su vida normal y comenzó de nuevo a jugar béisbol, debido a que desaparecieron la diplopía y el enoftalmo, por lo que tuvo una completa rehabilitación estética y funcional. En los exámenes radiográficos postoperatorios se observó una excelente reconstrucción del piso de la orbita y una osteointegegración del material implantológicoWe attend one patient, baseball player that suffer floor orbital fracture when he received hit in his eye (blowout) during practice baseball. He was operating and repaired this fracture with Porous Hidroxyapatite HAP-200.After operation he returned to play baseball because disappear the signs and symptoms (diplopia and enophthalmo).The radiography study showed excellent result after one yea

Oxidative stress is tightly regulated by cytochrome c phosphorylation and respirasome factors in mitochondria

Respiratory cytochrome c has been found to be phosphorylated at tyrosine 97 in the postischemic brain upon neuroprotective insulin treatment, but how such posttranslational modification affects mitochondrial metabolism is unclear. Here, we report the structural features and functional behavior of a phosphomimetic cytochrome c mutant, which was generated by site-specific incorporation at position 97 of p-carboxymethyl-l-phenylalanine using the evolved tRNA synthetase method. We found that the point mutation does not alter the overall folding and heme environment of cytochrome c, but significantly affects the entire oxidative phosphorylation process. In fact, the electron donation rate of the mutant heme protein to cytochrome c oxidase, or complex IV, within respiratory supercomplexes was higher than that of the wild-type species, in agreement with the observed decrease in reactive oxygen species production. Direct contact of cytochrome c with the respiratory supercomplex factor HIGD1A (hypoxia-inducible domain family member 1A) is reported here, with the mutant heme protein exhibiting a lower affinity than the wild-type species. Interestingly, phosphomimetic cytochrome c also exhibited a lower caspase-3 activation activity. Altogether, these findings yield a better understanding of the molecular basis for mitochondrial metabolism in acute diseases, such as brain ischemia, and thus could allow the use of phosphomimetic cytochrome c as a neuroprotector with therapeutic applications.España, Junta de Andalucía BIO-198España MINECO BFU2015-71017/BM

New approach to managing COVID-19 pandemic in a complex tertiary care medical centre in Madrid, Spain

The COVID-19 pandemic is putting healthcare systems under unprecedented stress to accommodate unexpected numbers of patients forcing a quick re-organization. This article describes the staff management experience of a third level referral hospital in the city of Madrid, Spain, one of the cities and hospitals with the largest number of COVID19 cases. A newly created COVID-19-specific Clinical Management Unit (CMU) coordinated all clinical departments and conducted real-time assessments of the availability and needs of medical staff, alongside the hospital's general management board. The Unit was able to (i) redeploy up to 285 physicians every week to bolster medical care in COVID-19 wards and forecast medical staff requirements for the upcoming week so all departments could organize their work while coping with COVID-19 needs, (ii) overview all clinical activities conducted in a medicalized hotel, and (iii) recruit a team of roughly 90 volunteer medical students to accelerate data collection and evidence generation. The main advantage of a clinical management unit composed by a member of every job category - its ability to generate rapid, locally-adapted responses to unexpected challenges - made it perfect for the unprecedented increase in healthcare need generated by the COVID-19 pandemic

Índice de Liam: prueba física funcional

Made very important test (Liam) in the medical students in Medical Faculty in Artemisa city, because with this examination proof the functional and physical conditions before and after training. All students after training received best results than before. It is very important to because the students obtained some abilities in this subject when will be doctorsSe realizó un análisis de la prueba funcional de Liam en un grupo de estudiantes de 2do año de Medicina de Artemisa con el objetivo de valorar el grado de aptitud cardiovascular y el nivel de entrenamiento de este grupo, donde se obtuvo que la mayoría de los estudiantes el 77,8% estaba apto físicamente y solo dos para un 22,2% se encontraba en la categoría de pobre en la prueba que se realizó al inicio del curso .Esta prueba es de gran utilidad en nuestra formación como futuro Medico Generales Integrales y sobre todo que es muy fácil su proceder y lo podemos aplicar en área de salud con nuestros pacientes ,una vez graduados como médicos .En el mes de Abril después de seis meses de práctica sistemática de ejercicios físicos todos los estudiantes mejoraron de forma considerable su aptitud cardiovascular y el nivel de entrenamiento a las categorías de muy bien y bie

Distributed feedback lasers based on dichromated poly(vinyl alcohol) reusable surface-relief gratings

A simple, low-cost and versatile holographic method to produce reusable surface-relief gratings on dichromated poly(vinyl alcohol) (DCPVA) films, with periods Λ ≥ 270 nm and modulation depths up to 300 nm, is reported. DCPVA presents processing advantages with respect to other photoresists, such as dichromated gelatine, i.e. higher light sensitivity, simpler fabrication process and better batch to batch reproducibility. The successful use of these DCPVA relief gratings as distributed feedback (DFB) laser resonators is demonstrated. Second-order DFB devices emitting in the wavelength range 577-614 nm have been easily prepared by coating a dye-doped polymer film on top of the resonators.We thank the Spanish Government (MINECO) and the European Union (FEDER) for grant no. MAT2011-28167-C02

Singular Temperatures Connected to Charge Transport Mechanism Transitions in Perylene Bisimides from Steady-State Photocurrent Measurements

Perylene bisimides (PBIs) are n-type semiconducting and photogenerating materials widely used in a variety of optoelectronic devices. Particularly interesting are PBIs that are simultaneously water-soluble and liquid-crystalline (PBI-W+LC) and, thus, attractive for the development of high-performing easily processable applications in biology and “green” organic electronics. In this work, singular temperatures connected to charge transport mechanism transitions in a PBI-W+LC derivative are determined with high accuracy by means of temperature-dependent photocurrent studies. These singular temperatures include not only the ones observed at 60 and 110 °C, corresponding to phase transition temperatures from crystalline to liquid-crystalline (LC) and from LC to the isotropic phase, respectively, as confirmed by differential scanning calorimetry (DSC), but also a transition at 45 °C, not observed by DSC. By analyzing the photocurrent dependence simultaneously on temperature and on light intensity, this transition is interpreted as a change from monomolecular to bimolecular recombination. These results might be useful for other semiconducting photogenerating materials, not necessarily PBIs or even organic semiconductors, which also show transport behavior changes at singular temperatures not connected with structural or phase transitions.We appreciate support from the Spanish government (MINECO) and the European Community (FEDER) through Grant MAT-2011-28167-C02-01, as well as the University of Alicante. We gratefully acknowledge financial support from MINECO (MAT2014-52305-P) and the UCM-BSCH joint project (GR3/14-910759). A. de la Peña thanks Universidad Complutense for a predoctoral fellowship

The atypical iron-coordination geometry of cytochrome f remains unchanged upon binding to plastocyanin, as inferred by XAS

The transient complex between cytochrome f and plastocyanin from the cyanobacterium Nostoc sp. PCC 7119 has been analysed by X-ray Absorption Spectroscopy in solution, using both proteins in their oxidized and reduced states. Fe K-edge data mainly shows that the atypical metal coordination geometry of cytochrome f, in which the N-terminal amino acid acts as an axial ligand of the heme group, remains unaltered upon binding to its redox partner, plastocyanin. This fact suggests that cytochrome f provides a stable binding site for plastocyanin and minimizes the reorganization energy required in the transient complex formation, which could facilitate the electron transfer between the two redox partners