Structural and functional analysis of the LaMDR1 multidrug resistance gene in Leishmania amazonensis

We determined primary sequences of the LaMDR1 gene in Leishmania amazonensis, a protozoan parasite that causes cutaneous leishmaniasis. The longest open reading frame encodes 1341 amino acids for a protein consisting of two similar halves, each containing six putative transmembrane domains and one ATP-binding domain. The protein has no potential N-glycosylation sites at the extracellular region. The LaMDR1 protein was 91 and 78% identical to the closely related ldmdr1 in L. donovani and lemdr1 in L. enriettii, respectively, revealing less conservation in the C-terminal than in the N-terminal transmembrane domains. Transfection of LaMDR1 conferred a multidrug resistance phenotype to wild-type promastigotes, which exhibited a significant level of resistance to vinblastine, doxorubicin, and actinomycin D, but not to puromycin and colchicine. This drug specificity of LaMDR1 was overlapping with but distinct from that of ldmdr1, suggesting functional diversity of MDR1 proteins among different Leishmania species.