Journal article
The Leishmania GDP-Mannose Transporter Is an Autonomous, Multi-specific, Hexameric Complex of LPG2 Subunits
Biochemistry (Easton), Vol.39(8), pp.2013-2022
02/29/2000
DOI: 10.1021/bi992363l
PMID: 10684651
Abstract
LPG2 (a gene involved in lipophosphoglycan assembly) encodes the Golgi GDP-Man transporter of the protozoan parasite Leishmania and is a defining member of a new family of eukaryotic nucleotide-sugar transporters (NSTs). Although NST activities are widespread, mammalian cells lack a GDP-Man NST, thereby providing an ideal heterologous system for probing the LPG2 structure and activity. LPG2 expression constructs introduced into either mammalian cells or a Leishmania lpg2 - mutant conferred GDP-Man, GDP-Ara, and GDP-Fuc (in Leishmania only) uptake in isolated microsomes. LPG2 is the first NST to be associated with multiple substrate specificities. Uptake activity showed latency, exhibited an antiport mechanism of transport with GMP, and was susceptible to the anion transport inhibitor DIDS. The apparent K m for GDP-Man uptake was similar in transfected mammalian cells (12.2 μM) or Leishmania (6.9 μM). Given the evolutionary distance between protozoans and vertebrates, these data suggest that LPG2 functions autonomously to provide transporter activity. Using epitope-tagged LPG2 proteins, we showed the existence of hexameric LPG2 complexes by immunoprecipitation experiments, glycerol gradient centrifugation, pore-limited native gel electrophoresis, and cross-linking experiments. This provides strong biochemical evidence for a multimeric complex of NSTs, a finding with important implications to the structure and specificity of NSTs in both Leishmania and other organisms. Inhibition of essential GDP-Man uptake in fungal and protozoan systems offers an attractive target for potential chemotherapy.
Details
- Title: Subtitle
- The Leishmania GDP-Mannose Transporter Is an Autonomous, Multi-specific, Hexameric Complex of LPG2 Subunits
- Creators
- Kyoungja HongDeqin MaStephen M BeverleySalvatore J Turco
- Resource Type
- Journal article
- Publication Details
- Biochemistry (Easton), Vol.39(8), pp.2013-2022
- Publisher
- American Chemical Society
- DOI
- 10.1021/bi992363l
- PMID
- 10684651
- ISSN
- 0006-2960
- eISSN
- 1520-4995
- Language
- English
- Date published
- 02/29/2000
- Academic Unit
- Pathology
- Record Identifier
- 9984047981502771
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