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Nucleotide sugar transporters of Trypanosoma brucei: glycosylation and infectivity
Author(s) -
Liu Li,
Xu Yu-Xin,
Burleigh Barbara A.,
Bangs James D.,
Hirschberg Carlos B.
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.606.1
Subject(s) - trypanosoma brucei , biology , infectivity , nucleotide sugar , glycosylation , virulence , glycoprotein , mutant , biochemistry , transporter , microbiology and biotechnology , gene , nucleotide , virology , virus
Trypanosoma brucei is the pathogenic agent of African trypanosomiasis. Sugars of surface glycoproteins play pivotal roles in parasite infectivity. A key step in glycosylation is transport of nucleotide sugars from the cytosol into the lumen of the Golgi apparatus by Nucleotide Sugar Transporters (NSTs). Mutations/deletions in these transporters have been shown to result in developmental diseases and impaired cell walls of yeast and pathogenic fungi. So far, no information about TbNSTs has been reported. Our goal is to understand how TbNSTs affect the pathogenicity of T. brucei by regulating the sugar modifications of its surface glycoproteins. We have identified four TbNSTs and characterized their substrate specificity by in vitro biochemical transport assays and phenotypic corrections of transport‐defective mutants such as K. lactis, MDCK cells and S. cerevisiae. Inhibition of TbNST4 gene expression in the procyclic‐form by RNAi resulted in underglycosylated procyclin, a major coat glycoprotein. Immunofluorescence staining also showed significant reduction of the surface procyclins in TbNST4‐silenced cells suggesting a transport defect and a change of surface glycoproteins. We are currently generating conditional TbNST knockout bloodstream‐forms to determine the parasite's virulence in a mouse infection model. Supported by NIH grants GM 30365 (CBH, LL and YXX), AI 35739 (JDB) and AI 090366 (BAB).