RESUMO
Irreversible oxidation of Cys residues to sulfinic/sulfonic forms typically impairs protein function. We found that persulfidation (CysSSH) protects Cys from irreversible oxidative loss of function by the formation of CysSSO1-3H derivatives that can subsequently be reduced back to native thiols. Reductive reactivation of oxidized persulfides by the thioredoxin system was demonstrated in albumin, Prx2, and PTP1B. In cells, this mechanism protects and regulates key proteins of signaling pathways, including Prx2, PTEN, PTP1B, HSP90, and KEAP1. Using quantitative mass spectrometry, we show that (i) CysSSH and CysSSO3H species are abundant in mouse liver and enzymatically regulated by the glutathione and thioredoxin systems and (ii) deletion of the thioredoxin-related protein TRP14 in mice altered CysSSH levels on a subset of proteins, predicting a role for TRP14 in persulfide signaling. Furthermore, selenium supplementation, polysulfide treatment, or knockdown of TRP14 mediated cellular responses to EGF, suggesting a role for TrxR1/TRP14-regulated oxidative persulfidation in growth factor responsiveness.
Assuntos
Cisteína/genética , Oxirredução/efeitos dos fármacos , Tiorredoxina Redutase 1/genética , Tiorredoxinas/genética , Animais , Cisteína/química , Fator de Crescimento Epidérmico/genética , Proteínas de Choque Térmico HSP90/genética , Proteínas de Homeodomínio/química , Proteínas de Homeodomínio/genética , Humanos , Proteína 1 Associada a ECH Semelhante a Kelch/genética , Camundongos , PTEN Fosfo-Hidrolase/genética , Proteína Tirosina Fosfatase não Receptora Tipo 1/genética , Selênio/farmacologia , Transdução de Sinais/efeitos dos fármacos , Sulfetos/metabolismo , Sulfetos/farmacologia , Tiorredoxina Redutase 1/química , Tiorredoxinas/químicaRESUMO
Quillaja saponaria (Quillay), an evergreen tree found in Chile, is one of the main sources of saponins. Quillaja saponins have hypocholesterolaemic, anticarcinogenic, antioxidant and pesticidal properties, and are used as adjuvants for vaccines. Samples of Quillay growing at three zones in O'Higgins Region, Chile (Coastal, Central and Mountain zones) were analyzed for content of saponins and physiological status. The results revealed differences in the content of saponins depending on the zone of sample collection. The highest contents were found in samples from the Mountain zone, where the highest saponin contents were accompanied by the lowest foliar nitrogen contents, the highest antioxidant activity and the highest carotenoid contents. The results suggest a physiological and adaptive mechanism of saponins in plants to survive under unfavourable environmental conditions. The results have important implications for a theoretical basis for the design of a reasonable harvest, to avoid the cost of poor quality material, and also to provide a sustainable use and conservation of this important species. Further research on the effects of stress will improve our understanding of the saponins production and their physiological functions in plants, whereas they have generally been studied for their biological and chemical applications.
Assuntos
Ecossistema , Quillaja/química , Saponinas/isolamento & purificação , Antioxidantes/análise , Plantas Medicinais/química , Plantas Medicinais/fisiologia , Quillaja/fisiologiaRESUMO
From the non-coloured fraction of rhizomes of Aristolochia brevipes (Aristolochiaceae) the new aporphine alkaloid 6a,7-dehydro- N-formylnornantenine was isolated besides N-formylnornantenine, cadalene, and 4-hydroxy-4,7-dimethyl-1-tetralone.