Leishmania LABCG2 transporter is involved in ATP-dependent transport of thiols.

The Leishmania LABCG2 transporter has a key role in the redox metabolism of these protozoan parasites. Recently, it has been described the involvement of LABCG2 in virulence, autophagy and oxidative stress. Null mutant parasites for LABCG2 present an increase in the intracellular levels of glutathione (GSH) and trypanothione [T(SH)2]. On the other hand, parasites overexpressing LABCG2 transporter export non-protein thiols to the extracellular medium. In order to explore if LABCG2 may mediate an active transport of non-protein thiols, the effect of these molecules on ATPase activity of LABCG2 as well as the ability of LABCG2 to transport them was determined using a baculovirus-Sf9 insect cell system. Our results indicate that all thiols tested [GSH, T(SH)2] as well as their oxidized forms GSSG and TS2 stimulate LABCG2-ATPase basal activity. We have measured the transport of [3H]-GSH in inside-out Sf9 cells membrane vesicles expressing LABCG2-GFP finding that LABCG2 was able to mediate a rapid and concentration dependent uptake of [3H]-GSH in presence of ATP. Finally, we have analyzed the ability of different thiol species to compete for this uptake, being the best competitors T(SH)2 and TS2 IC50 value for [3H]-GSH uptake in presence of increasing concentrations of T(SH)2 was less than 100 mM, highlighting the affinity of this thiol for LABCG2. These results provide the first direct evidence that LABCG2 is an ABC transporter of reduced and oxidized non-protein thiols in Leishmania , suggesting that this transporter can play a role in the redox metabolism and related processes in this protozoan parasite. ©2017 The Author(s).

Citation

Ana Perea, José Ignacio Manzano, Yasuhisa Kimura, Kazumitsu Ueda, Santiago Castanys, Francisco Gamarro. Leishmania LABCG2 transporter is involved in ATP-dependent transport of thiols. The Biochemical journal. 2017 Nov 21

PMID: 29162656

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