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1.
PLoS One ; 13(1): e0191423, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29373579

RESUMEN

Stimulation of renal collecting duct principal cells with antidiuretic hormone (arginine-vasopressin, AVP) results in inhibition of the small GTPase RhoA and the enrichment of the water channel aquaporin-2 (AQP2) in the plasma membrane. The membrane insertion facilitates water reabsorption from primary urine and fine-tuning of body water homeostasis. Rho guanine nucleotide exchange factors (GEFs) interact with RhoA, catalyze the exchange of GDP for GTP and thereby activate the GTPase. However, GEFs involved in the control of AQP2 in renal principal cells are unknown. The A-kinase anchoring protein, AKAP-Lbc, possesses GEF activity, specifically activates RhoA, and is expressed in primary renal inner medullary collecting duct principal (IMCD) cells. Through screening of 18,431 small molecules and synthesis of a focused library around one of the hits, we identified an inhibitor of the interaction of AKAP-Lbc and RhoA. This molecule, Scaff10-8, bound to RhoA, inhibited the AKAP-Lbc-mediated RhoA activation but did not interfere with RhoA activation through other GEFs or activities of other members of the Rho family of small GTPases, Rac1 and Cdc42. Scaff10-8 promoted the redistribution of AQP2 from intracellular vesicles to the periphery of IMCD cells. Thus, our data demonstrate an involvement of AKAP-Lbc-mediated RhoA activation in the control of AQP2 trafficking.


Asunto(s)
Proteínas de Anclaje a la Quinasa A/metabolismo , Acuaporina 2/metabolismo , Membrana Celular/metabolismo , Túbulos Renales Colectores/citología , Antígenos de Histocompatibilidad Menor/metabolismo , Proteínas Proto-Oncogénicas/metabolismo , Bibliotecas de Moléculas Pequeñas/farmacología , Proteína de Unión al GTP rhoA/metabolismo , Membrana Celular/efectos de los fármacos , Células HEK293 , Humanos , Unión Proteica/efectos de los fármacos , Transporte de Proteínas/efectos de los fármacos , Bibliotecas de Moléculas Pequeñas/química , Relación Estructura-Actividad
2.
J Mol Model ; 19(6): 2567-72, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23463266

RESUMEN

With the help of theoretical calculations we explain the phenomenon of nonplanarity of crystalline alternariol. We find out that the different orientations of the hydroxyl groups of alternariol influence its planarity and aromaticity and lead to different twists of the structure. The presence of the intramolecular hydrogen bond stabilizes the planar geometry while the loss of the bond results in a twist of over 14°. This effect is thought to be involved while cutting DNA strands by alternariol.


Asunto(s)
Lactonas/química , Modelos Moleculares , Teoría Cuántica , Conformación Molecular
3.
AIDS Res Hum Retroviruses ; 28(11): 1397-403, 2012 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-22931114

RESUMEN

Sexual transmission of HIV is the major cause of spread of HIV in Africa and the Third World and is an unmet medical need. Recently, microbicides have attracted attention because they allow females to protect themselves and their offspring. We are exploiting one of the four retroviral enzymes, the ribonuclease H, RNase H, as a novel approach for a microbicide. It is the only enzyme of HIV not yet targeted by antiretroviral therapy. The enzyme is linked to the reverse transcriptase (RT) and hydrolyzes the RNA moiety of RNA-DNA hybrids. The RNase H is located inside virus particles and normally functions during viral replication inside cells. Here we show that activating the RNase H prematurely inside the virus particles destroys the viral genome and abrogates viral infectivity. The antiviral compound consists of a synthetic oligodeoxynucleotide (ODN), which creates an artificial RNA-DNA hybrid substrate for the RNase H inside the particle. The compound was analyzed in mouse models including humanized SCID mice and the vagina of mice. Infection was reduced up to 1000-fold or could be completely prevented. The compound is suitable as microbicide or to prevent mother-to-child transmission.


Asunto(s)
Antiinfecciosos/farmacología , Activación Enzimática/inmunología , Infecciones por VIH/inmunología , Infecciones por VIH/prevención & control , VIH-1/inmunología , Ribonucleasa H del Virus de la Inmunodeficiencia Humana/inmunología , Vagina/inmunología , Animales , Células Cultivadas , Modelos Animales de Enfermedad , Activación Enzimática/efectos de los fármacos , Femenino , Infecciones por VIH/tratamiento farmacológico , VIH-1/enzimología , Humanos , Masculino , Ratones , Ratones SCID , ARN Viral/efectos de los fármacos , Vagina/efectos de los fármacos , Carga Viral , Replicación Viral/efectos de los fármacos
4.
J Chromatogr A ; 1217(15): 2206-15, 2010 Apr 09.
Artículo en Inglés | MEDLINE | ID: mdl-20207360

RESUMEN

A novel, cost-efficient method for the analytical extraction of the Fusarium mycotoxin zearalenone (ZON) from edible oils by dynamic covalent hydrazine chemistry (DCHC) was developed and validated for its application with high performance liquid chromatography-fluorescence detection (HPLC-FLD). ZON is extracted from the edible oil by hydrazone formation on a polymer resin functionalised with hydrazine groups and subsequently released by hydrolysis. Specifity and precision of this approach are superior to liquid partitioning or gel permeation chromatography (GPC). DCHC also extracts zearalanone (ZAN) but not alpha-/beta-zearalenol or -zearalanol. The hydrodynamic properties of ZON, which were estimated using molecular simulation data, indicate that the compound is unaffected by nanofiltration through the resin pores and thus selectively extracted. The method's levels of detection and quantification are 10 and 30 microg/kg, using 0.2g of sample. Linearity is given in the range of 10-20,000 microg/kg, the average recovery being 89%. Bias and relative standard deviations do not exceed 7%. In a sample survey of 44 commercial edible oils based on various agricultural commodities (maize, olives, nuts, seeds, etc.) ZON was detected in four maize oil samples, the average content in the positive samples being 99 microg/kg. The HPLC-FLD results were confirmed by HPLC-tandem mass spectrometry and compared to those obtained by a liquid partitioning based sample preparation procedure.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Fusarium/química , Hidrazinas/química , Aceites de Plantas/química , Zearalenona/análisis , Zearalenona/aislamiento & purificación , Ácidos/química , Catálisis , Simulación por Computador , Polímeros/química , Reproducibilidad de los Resultados , Resinas Sintéticas/química , Solventes/química , Factores de Tiempo , Agua/química , Zearalenona/análogos & derivados , Zearalenona/química
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