title: Reduced antimony accumulation in ARM58-overexpressing Leishmania infantum.
abstract: Antimony-based drugs are still the mainstay of chemotherapy against Leishmania infections in many countries where the parasites are endemic. The efficacy of antimonials has been compromised by increasing numbers of resistant infections, the basis of which is not fully understood and likely involves multiple factors. By using a functional cloning strategy, we recently identified a novel antimony resistance marker, ARM58, from the parasite Leishmania braziliensis that protects the parasites against antimony-based antileishmanial compounds. Here we show that the Leishmania infantum homologue also confers resistance against antimony but not against other antileishmanial drugs and that its function depends critically on one of four conserved domains of unknown function. This critical domain requires at least two hydrophobic amino acids and is predicted to form a transmembrane structure. Overexpression of ARM58 in antimony-exposed parasites reduces the intracellular Sb accumulation by over 70%, indicating a role for ARM58 in Sb extrusion pathways, but without involvement of energy-dependent transporter proteins.
authors.affiliation: Bernhard Nocht Institute for Tropical Medicine, Hamburg, Germany.
authors.forename: Carola
authors.initials: C
authors.lastname: Schäfer
authors.forename: Paloma
authors.initials: P
authors.lastname: Tejera Nevado
authors.forename: Dorothea
authors.initials: D
authors.lastname: Zander
authors.forename: Joachim
authors.initials: J
authors.lastname: Clos
mesh_terms: D000965:Antimony / Q000032:analysis / Q000378:metabolism / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004351:Drug Resistance / Q000235:genetics; D005786:Gene Expression Regulation / Q000235:genetics; D017125:Genes, Protozoan / Q000235:genetics*; D005819:Genetic Markers / Q000235:genetics; D066298:In Vitro Techniques; D018314:Leishmania infantum / Q000737:chemistry / Q000187:drug effects* / Q000235:genetics; D014344:Trypanocidal Agents / Q000032:analysis / Q000494:pharmacology*
chemical_list: D005819:Genetic Markers; D014344:Trypanocidal Agents; D000965:Antimony