Another simpler proton pump that co-localizes with the V-ATPase occurs in plants and many protists: the single-subunit H(+)-PPase [H(+)-translocating PPase (inorganic pyrophosphatase)]. Little is known about the relative contribution of these two proteins to the acidification of intracellular compartments. In the present study, we show that the expression

of a chimaeric derivative of the Transmembrane Transporters inhibitor A rabidopsis thaliana H(+)-PPhase AVP1, which is preferentially targeted to internal membranes of yeast, alleviates the phenotypes associated with V-ATPase deficiency. Phenotypic complementation was achieved both with a yeast strain with its V-ATPase specifically inhibited by bafilomycin A1 and with a vma1-null mutant lacking a catalytic V-ATPase subunit. Cell staining with vital fluorescent dyes showed that AVP1 recovered vacuole acidification and normalized the endocytic pathway of the vow mutant. Biochemical and immunochemical studies further demonstrated that a significant

fraction of heterologous H(+)-PPase is located at the vacuolar membrane. These results raise Selleck SB273005 the question of the occurrence of distinct proton pumps in certain single-membrane organelles, such as plant vacuoles, by proving yeast V-ATPase activity dispensability and the capability of H(+)-PPase to generate, by itself, physiologically suitable internal pH gradients. Also, they suggest new ways of engineering macrolide drug tolerance and outline an experimental system for testing alternative roles for fungal and animal V-ATPases, other than the mere acidification of subcellular organelles.”
“DEAD box helicases unwind RNA duplexes at the expense

of ATP hydrolysis. Recently, unwinding has been demonstrated in the absence of ATP hydrolysis. Herein, we show that ADP . BeF(x) supports RNA unwinding by YxiN, a DEAD box helicase that specifically recognizes a hairpin in 23S rRNA. ADP-AlF(x) and ADP.MgF(x) do not promote RNA unwinding, but all ATP analogues induce a closed conformation of the helicase core as required for RNA unwinding. Our results show that the interdomain cleft in the helicase core closes upon ATP binding at the beginning of the cycle. Reopening Fludarabine occurs after ATP hydrolysis, most likely coupled to phosphate release.”
“Obesity, type-2 diabetes and low-grade inflammation are becoming worldwide epidemics. In this regard, the literature provides a novel concept that we call “MicrObesity” (Microbes and Obesity), which is devoted to deciphering the specific role of dysbiosis and its impact on host metabolism and energy storage. In the present review, we discuss novel findings that may partly explain how the microbial community participates in the development of the fat mass development, insulin resistance and low-grade inflammation that characterise obesity.