title: KHARON1 mediates flagellar targeting of a glucose transporter in Leishmania mexicana and is critical for viability of infectious intracellular amastigotes.
abstract: The LmxGT1 glucose transporter is selectively targeted to the flagellum of the kinetoplastid parasite Leishmania mexicana, but the mechanism for targeting this and other flagella-specific membrane proteins among the Kinetoplastida is unknown. To address the mechanism of flagellar targeting, we employed in vivo cross-linking, tandem affinity purification, and mass spectrometry to identify a novel protein, KHARON1 (KH1), which is important for the flagellar trafficking of LmxGT1. Kh1 null mutant parasites are strongly impaired in flagellar targeting of LmxGT1, and trafficking of the permease was arrested in the flagellar pocket. Immunolocalization revealed that KH1 is located at the base of the flagellum, within the flagellar pocket, where it associates with the proximal segment of the flagellar axoneme. We propose that KH1 mediates transit of LmxGT1 from the flagellar pocket into the flagellar membrane via interaction with the proximal portion of the flagellar axoneme. KH1 represents the first component involved in flagellar trafficking of integral membrane proteins among parasitic protozoa. Of considerable interest, Kh1 null mutants are strongly compromised for growth as amastigotes within host macrophages. Thus, KH1 is also important for the disease causing stage of the parasite life cycle.
authors.affiliation: Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, Oregon 97239, USA.
authors.forename: Khoa D
authors.initials: KD
authors.lastname: Tran
authors.forename: Dayana
authors.initials: D
authors.lastname: Rodriguez-Contreras
authors.forename: Danielle P
authors.initials: DP
authors.lastname: Vieira
authors.forename: Phillip A
authors.initials: PA
authors.lastname: Yates
authors.forename: Larry
authors.initials: L
authors.lastname: David
authors.forename: Wandy
authors.initials: W
authors.lastname: Beatty
authors.forename: Johannes
authors.initials: J
authors.lastname: Elferich
authors.forename: Scott M
authors.initials: SM
authors.lastname: Landfear
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D002846:Chromatography, Affinity; D017931:DNA Primers; D005407:Flagella / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D007894:Leishmania mexicana / Q000378:metabolism*; D008969:Molecular Sequence Data; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D021381:Protein Transport; D015800:Protozoan Proteins / Q000737:chemistry / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid
chemical_list: D017931:DNA Primers; D009004:Monosaccharide Transport Proteins; D015800:Protozoan Proteins; D005947:Glucose
keywords: Amastigote Viability; Flagellar Membrane Protein Targeting; Glucose Transport; Glucose Transporter; Leishmania; Mass Spectrometry (MS); Pathogenesis; Protein Targeting; TAP Tagging