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Actin cytoskeleton disruption is an early event upon exposure of cerebellar gra...
Tiago, Teresa; Silva, D.; Samhan-Arias, A. K.; Aureliano, M.; Gutiérrez-Merino, CarlosIn this work we have studied the alterations of the actin cytoskeleton in cultured cerebellar granule neurons during exposure to the peroxynitritereleasing agent SIN-1 for less than 2 hours. Actin polymerization state was assessed by fluorescence microscopy ratio images using double labelling for actin filaments (phallacidin) and monomers (DNase-I). In addition, agonists and antagonists of L-type Ca2+ channels ...
Sarcoplasmic reticulum calcium ATPase is inhibited by organic vanadium coordina...
Aureliano, Manuel; Henao, Fernando; Tiago, Teresa; Duarte, Rui O.; Moura, José J. G.; Baruah, Bharat; Crans, Debbie C.Inorg Chem. 2008 Jul 7;47(13):5677-84. doi: 10.1021/ic702405d ; The general affinity of the sarcoplasmic reticulum (SR) Ca (2+)-ATPase was examined for three different classes of vanadium coordination complexes including a vanadium(V) compound, pyridine-2,6-dicarboxylatodioxovanadium(V) (PDC-V(V)), and two vanadium(IV) compounds, bis(maltolato)oxovanadium(IV) (BMOV), and an analogue of amavadine, bis( N-hydrox...
Effects of reactive oxygen and nitrogen species on actomyosin and their implica...
Tiago, Teresa; Aureliano, M.; Gutiérrez-Merino, CarlosExperimental evidence accumulated during recent years is pointing out that numerous pathological conditions in skeletal and cardiac muscle are associated with an oxidative stress-induced muscle injury. Additionally, it has been postulated that several oxidants can directly alter contractile function by oxidative modification of the myofibril proteins – actin and myosin. Peroxynitrite (ONOO-), a potent biologica...
Binding modes of decavanadate to myosin and inhibition of the actomyosin ATPase...
Tiago, Teresa; Martel, Paulo; Gutiérrez-Merino, Carlos; Aureliano, M.Decavanadate, a vanadate oligomer, is known to interact with myosin and to inhibit the ATPase activity, but the putative binding sites and the mechanism of inhibition are still to be clarified. We have previously proposed that the decavanadate (V10O28 6−) inhibition of the actin-stimulated myosin ATPase activity is non-competitive towards both actin and ATP. A likely explanation for these results is that V10 bi...
Monomeric versus decameric vanadate in the elucidation of muscle contraction re...
Tiago, Teresa; Gutiérrez-Merino, Carlos; Aureliano, M.Vanadium (V) was rediscovered for biology as a “muscle inhibitor factor” when it was found in commercial ATP prepared from equine muscle almost thirty years ago. Since then it has been used as a molecular probe of the mechanisms of several enzyme reactions involving hydrolysis of phosphate ester bonds. Besides acting as a phosphate analogue, vanadate has also the potential to exhibit biological activities throu...
Actomyosin modulation by peroxynitrite
Tiago, Teresa; Silva, D.; Santos, A.; Aureliano, M.; Gutiérrez-Merino, CarlosIn the present work we address the oxidative modifications accounting for the structural and functional impairment of the actomyosin complex under the oxidative stress mediated by peroxynitrite (ONOO-). Experiments on purified myosin and actin have shown that submicromolar ONOO- concentrations produce strong inhibition of the F-actin stimulated myosin ATPase activity. The peroxynitrite-induced actomyosin impair...
Peroxynitrite induces F-actin depolymerization and blockade of myosin ATPase st...
Tiago, Teresa; Ramos, Susana; Aureliano, M.; Gutiérrez-Merino, CarlosTreatment of F-actin with the peroxynitrite-releasing agent 3-morpholinosydnonimine (SIN-1) produced a dose-dependent F-actin depolymerization. This is due to released peroxynitrite because it is not produced by ‘decomposed SIN-1’, and it is prevented by superoxide dismutase concentrations efficiently preventing peroxynitrite formation. F-actin depolymerization has been found to be very sensitive to peroxynitri...
Decavanadate interactions with actin: inhibition of G-actin polymerization and ...
Ramos, Susana; Manuel, Miguel; Tiago, Teresa; Duarte, Rui O.; Martins, Jorge; Gutiérrez-Merino, Carlos; Moura, José J. G.; Aureliano, M.Decameric vanadate species (V10) inhibit the rate and the extent of G-actin polymerization with an IC50 of 68 ± 22 lM and 17 ± 2 lM, respectively, whilst they induce F-actin depolymerization at a lower extent. On contrary, no effect on actin polymerization and depolymerization was detected for 2 mM concentration of ‘‘metavanadate’’ solution that contains ortho and metavanadate species, as observed by combining ...
Inhibition of skeletal muscle S1-myosin ATPase by peroxynitrite
Tiago, Teresa; Simão, Sónia; Aureliano, M.; Martín-Romero, Francisco Javier; Gutiérrez-Merino, CarlosExposure of myosin subfragment 1 (S1) to 3-morpholinosydnonimine (SIN-1) produced a time-dependent inhibition of the F-actin-stimulated S1 Mg2+-ATPase activity, reaching 50% inhibition with 46.7 ( 8.3 íM SIN-1 for 8.7 íM S1, that is, at a SIN-1/S1 molar ratio of approximately 5.5. The inhibition was due to the peroxynitrite produced by SIN-1 decomposition because (1) decomposed SIN-1 was found to have no effect...
Interactions of vanadium(V)–citrate complexes with the sarcoplasmic reticulum c...
Aureliano, M.; Tiago, Teresa; Gândara, Ricardo M. C.; Sousa, Andrea; Moderno, A.; Kaliva, M.; Salifoglou, A.; Duarte, Rui O.; Moura, José J. G.Among the biotargets interacting with vanadium is the calcium pump from the sarcoplasmic reticulum (SR). To this end, initial research efforts were launched with two vanadium(V)–citrate complexes, namely (NH4)6[V2O4(C6H4O7)2] Æ 6H2O and (NH4)6[V2O2(O2)2(C6H4O7)2] Æ 4H2O, potentially capable of interacting with the SR calcium pump by combining kinetic studies with 51V NMR spectroscopy. Upon dissolution in the re...
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