title: Cytoskeletal association is important for differential targeting of glucose transporter isoforms in Leishmania.
abstract: The major glucose transporter of the parasitic protozoan Leishmania enriettii exists in two isoforms, one of which (iso-1) localizes to the flagellar membrane, while the other (iso-2) localizes to the plasma membrane of the cell body, the pellicular membrane. These two isoforms differ only in their cytosolic NH2-terminal domains. Using immunoblots and immunofluorescence microscopy of detergent-extracted cytoskeletons, we have demonstrated that iso-2 associates with the microtubular cytoskeleton that underlies the cell body membrane, whereas the flagellar membrane isoform iso-1 does not associate with the cytoskeleton. Deletion mutants that remove the first 25 or more amino acids from iso-1 are retargeted from the flagellum to the pellicular membrane, suggesting that these deletions remove a signal required for flagellar targeting. Unlike the full-length iso-1 protein, these deletion mutants associate with the cytoskeleton. Our results suggest that cytoskeletal binding serves as an anchor to localize the iso-2 transporter within the pellicular membrane, and that the flagellar targeting signal of iso-1 diverts this transporter into the flagellar membrane and away from the pellicular microtubules.
authors.affiliation: Department of Molecular Microbiology and Immunology, Oregon Health Sciences University, Portland, Oregon 97201, USA.
authors.forename: E L
authors.initials: EL
authors.lastname: Snapp
authors.forename: S M
authors.initials: SM
authors.lastname: Landfear
mesh_terms: D000818:Animals; D001665:Binding Sites; D002458:Cell Fractionation; D003599:Cytoskeleton / Q000378:metabolism*; D003902:Detergents / Q000494:pharmacology; D018985:Epitopes, B-Lymphocyte; D005407:Flagella / Q000378:metabolism; D051273:Glucose Transporter Type 2; D018313:Leishmania enriettii / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D009004:Monosaccharide Transport Proteins / Q000235:genetics / Q000378:metabolism*; D017830:Octoxynol / Q000494:pharmacology; D021382:Protein Sorting Signals / Q000378:metabolism; D051381:Rats; D012995:Solubility
chemical_list: D003902:Detergents; D018985:Epitopes, B-Lymphocyte; D051273:Glucose Transporter Type 2; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins; D021382:Protein Sorting Signals; D017830:Octoxynol