Endosome sorting and autophagy are essential for differentiation and virulence of Leishmania major.
Cellular remodeling during differentiation is essential for life-cycle progression of many unicellular eukaryotic pathogens such as Leishmania, but the mechanisms involved are largely uncharacterized. The role of endosomal sorting in differentiation was analyzed in Leishmania major by overexpression of a dominant-negative ATPase, VPS4. VPS4(E235Q) accumulated in vesicles from the endocytic pathway, and the mutant L. major was deficient in endosome sorting. Mutant parasites failed to differentiate to the obligate infective metacyclic promastigote form. Furthermore, the autophagy pathway, monitored via the expression of autophagosome marker GFP-ATG8, and shown to normally peak during initiation of metacyclogenesis, was disrupted in the mutants. The defect in late endosome-autophagosome function in the VPS4(E235Q) parasites made them less able to withstand starvation than wild-type L. major. In addition, a L. major ATG4-deficient mutant was found also to be defective in the ability to differentiate. This finding, that transformation to the infective metacyclic form is dependent on late endosome function and, more directly, autophagy, makes L. major a good model for studying the roles of these processes in differentiation.
Wellcome Centre for Molecular Parasitology, University of Glasgow, 120 University Place, Glasgow G12 8TA, United Kingdom.
Sébastien
S
Besteiro
Roderick A M
RA
Williams
Lesley S
LS
Morrison
Graham H
GH
Coombs
Jeremy C
JC
Mottram
D000818:Animals; D001343:Autophagy; D015153:Blotting, Western; D002460:Cell Line; D004247:DNA / Q000378:metabolism; D017931:DNA Primers / Q000737:chemistry; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism / Q000382:microbiology*; D005799:Genes, Dominant; D049452:Green Fluorescent Proteins / Q000737:chemistry / Q000378:metabolism; D015151:Immunoblotting; D007891:Leishmania; D008247:Lysosomes / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism; D008856:Microscopy, Fluorescence; D008957:Models, Genetic; D009154:Mutation; D010957:Plasmids / Q000378:metabolism; D021381:Protein Transport; D013997:Time Factors; D014617:Vacuoles / Q000378:metabolism; D014774:Virulence
D017931:DNA Primers; D049452:Green Fluorescent Proteins; D004247:DNA