title: Plasma membrane-located purine nucleotide transport proteins are key components for host exploitation by microsporidian intracellular parasites.
abstract: Microsporidia are obligate intracellular parasites of most animal groups including humans, but despite their significant economic and medical importance there are major gaps in our understanding of how they exploit infected host cells. We have investigated the evolution, cellular locations and substrate specificities of a family of nucleotide transport (NTT) proteins from Trachipleistophora hominis, a microsporidian isolated from an HIV/AIDS patient. Transport proteins are critical to microsporidian success because they compensate for the dramatic loss of metabolic pathways that is a hallmark of the group. Our data demonstrate that the use of plasma membrane-located nucleotide transport proteins (NTT) is a key strategy adopted by microsporidians to exploit host cells. Acquisition of an ancestral transporter gene at the base of the microsporidian radiation was followed by lineage-specific events of gene duplication, which in the case of T. hominis has generated four paralogous NTT transporters. All four T. hominis NTT proteins are located predominantly to the plasma membrane of replicating intracellular cells where they can mediate transport at the host-parasite interface. In contrast to published data for Encephalitozoon cuniculi, we found no evidence for the location for any of the T. hominis NTT transporters to its minimal mitochondria (mitosomes), consistent with lineage-specific differences in transporter and mitosome evolution. All of the T. hominis NTTs transported radiolabelled purine nucleotides (ATP, ADP, GTP and GDP) when expressed in Escherichia coli, but did not transport radiolabelled pyrimidine nucleotides. Genome analysis suggests that imported purine nucleotides could be used by T. hominis to make all of the critical purine-based building-blocks for DNA and RNA biosynthesis during parasite intracellular replication, as well as providing essential energy for parasite cellular metabolism and protein synthesis.
authors.affiliation: Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom; Department of Microbiology, Monash University, Melbourne, Victoria, Australia; Victoria Bioinformatics Consortium, Monash University, Melbourne, Victoria, Australia.
authors.forename: Eva
authors.initials: E
authors.lastname: Heinz
authors.affiliation: School of Medicine, University of St. Andrews, St. Andrews, United Kingdom.
authors.forename: Christian
authors.initials: C
authors.lastname: Hacker
authors.affiliation: Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Paul
authors.initials: P
authors.lastname: Dean
authors.affiliation: Medical Research Council, Mitochondrial Biology Unit, Cambridge, United Kingdom.
authors.forename: John
authors.initials: J
authors.lastname: Mifsud
authors.affiliation: Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Alina V
authors.initials: AV
authors.lastname: Goldberg
authors.affiliation: Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Tom A
authors.initials: TA
authors.lastname: Williams
authors.affiliation: Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Sirintra
authors.initials: S
authors.lastname: Nakjang
authors.affiliation: Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Alison
authors.initials: A
authors.lastname: Gregory
authors.affiliation: Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: Robert P
authors.initials: RP
authors.lastname: Hirt
authors.affiliation: School of Medicine, University of St. Andrews, St. Andrews, United Kingdom.
authors.forename: John M
authors.initials: JM
authors.lastname: Lucocq
authors.affiliation: Medical Research Council, Mitochondrial Biology Unit, Cambridge, United Kingdom.
authors.forename: Edmund R S
authors.initials: ER
authors.lastname: Kunji
authors.affiliation: Institute for Cell and Molecular Biosciences, The Medical School, Newcastle University, Newcastle upon Tyne, United Kingdom.
authors.forename: T Martin
authors.initials: TM
authors.lastname: Embley
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000382:microbiology; D001693:Biological Transport, Active / Q000502:physiology; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D004271:DNA, Fungal / Q000096:biosynthesis / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D016814:Microsporidia / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D011685:Purine Nucleotides / Q000378:metabolism*; D012331:RNA, Fungal / Q000096:biosynthesis / Q000235:genetics
chemical_list: D002352:Carrier Proteins; D004271:DNA, Fungal; D005656:Fungal Proteins; D011685:Purine Nucleotides; D012331:RNA, Fungal