title: Bi-functionality of Opisthorchis viverrini aquaporins.
abstract: Aquaporins (AQP) are essential mediators of water regulation in all living organisms and members of the major intrinsic protein (MIP) superfamily of integral membrane proteins. They are potential vehicles or targets for chemotherapy, e.g. in Trypanosoma brucei melarsoprol and pentamidine uptake is facilitated by TbAQP-2. Transcriptome data suggests that there are at least three active aquaporins in the human liver fluke, Opisthorchis viverrini, OvAQP-1, 2 and 3, and crude RNA silencing of OvAQP-1 and 2 has recently been shown to affect parasite swelling in destilled water. In the present work we demonstrate that OvAQP-3 is a major water-conducting channel of the parasite, that it can be detected from the newly excysted juvenile to the adult stage and that it is present in major tissues of the parasite. Furthermore, a comparative functional characterization of the three parasite AQPs was performed by using Xenopus oocyte swelling and yeast phenotypic assays. OvAQP-1, OvAQP-2, and OvAQP-3 were found to conduct water and glycerol while only the latter two were also able to conduct urea. In addition, all OvAQPs were found to transport ammonia and methylamine. Our findings demonstrate that the sequence-based classification into orthodox aquaporins and glycerol-conducting aquaglyceroporins is not functionally conserved in the parasite and implicate a broder range of functions for these channels.
authors.affiliation: Graduate Program in Biomedical Sciences, Faculty of Allied Health Sciences, Thammasat University, Pathumthani 12121, Thailand.
authors.forename: Amornrat
authors.initials: A
authors.lastname: Geadkaew
authors.affiliation: Pharmazeutisches Institut, Christian-Albrechts-Universität, Kiel 24118, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: von Bülow
authors.affiliation: Pharmazeutisches Institut, Christian-Albrechts-Universität, Kiel 24118, Germany.
authors.forename: Eric
authors.initials: E
authors.lastname: Beitz
authors.affiliation: Food-borne Parasite Research Group, Department of Parasitology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Smarn
authors.initials: S
authors.lastname: Tesana
authors.affiliation: Department of Biology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand.
authors.forename: Suksiri
authors.initials: S
authors.lastname: Vichasri Grams
authors.affiliation: Graduate Program in Biomedical Sciences, Faculty of Allied Health Sciences, Thammasat University, Pathumthani 12121, Thailand. Electronic address: rgrams@tu.ac.th.
authors.forename: Rudi
authors.initials: R
authors.lastname: Grams
mesh_terms: D000595:Amino Acid Sequence; D000641:Ammonia / Q000378:metabolism; D000818:Animals; D020346:Aquaporins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D006224:Cricetinae; D017753:Ecosystem; D018507:Gene Expression Regulation, Developmental; D005990:Glycerol / Q000378:metabolism; D008744:Methylamines / Q000378:metabolism; D008969:Molecular Sequence Data; D009865:Oocytes / Q000378:metabolism; D009891:Opisthorchis / Q000254:growth & development; D010539:Permeability; D021381:Protein Transport; D017421:Sequence Analysis; D014508:Urea / Q000378:metabolism; D014867:Water / Q000378:metabolism; D014981:Xenopus
chemical_list: D020346:Aquaporins; D008744:Methylamines; D014867:Water; D000641:Ammonia; D014508:Urea; C027451:methylamine; D005990:Glycerol
keywords: Aquaporin; Comparative functional assays; Opisthorchis viverrini; Platyhelminthes