title: Identification of a reticulocyte-specific binding domain of Plasmodium vivax reticulocyte-binding protein 1 that is homologous to the PfRh4 erythrocyte-binding domain.
abstract: The Plasmodium vivax reticulocyte-binding protein (RBP) family was identified based on the annotation of adhesive ligands in the P. vivax genome. Reticulocyte-specific interactions with the PvRBPs (PvRBP1 and PvRBP2) were previously reported. Plasmodium falciparum reticulocyte-binding protein homologue 4 (PfRh4, a homologue of PvRBP1) was observed to possess erythrocyte-binding activity via complement receptor 1 on the erythrocyte surface. However, the reticulocyte-binding mechanisms of P. vivax are unclear because of the large molecular mass of PvRBP1 (>326 kDa) and the difficulty associated with in vitro cultivation. In the present study, 34 kDa of PvRBP1a (PlasmoDB ID: PVX_098585) and 32 kDa of PvRBP1b (PVX_098582) were selected from a 30 kDa fragment of PfRh4 for reticulocyte-specific binding activity analysis. Both PvRBP1a and PvRBP1b were found to be localized at the microneme in the mature schizont-stage parasites. Naturally acquired immune responses against PvRBP1a-34 and PvRBP1b-32 were observed lower than PvDBP-RII. The reticulocyte-specific binding activities of PvRBP1a-34 and PvRBP1b-32 were significantly higher than normocyte binding activity and were significantly reduced by chymotrypsin treatment. PvRBP1a and 1b, bind to reticulocytes and that this suggests that these ligands may have an important role in P. vivax merozoite invasion.
authors.affiliation: Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea.
authors.forename: Jin-Hee
authors.initials: JH
authors.lastname: Han
authors.affiliation: Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea.
authors.forename: Seong-Kyun
authors.initials: SK
authors.lastname: Lee
authors.affiliation: Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea.|Department of Clinical Laboratory, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, People's Republic of China.
authors.forename: Bo
authors.initials: B
authors.lastname: Wang
authors.affiliation: Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea.
authors.forename: Fauzi
authors.initials: F
authors.lastname: Muh
authors.affiliation: Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea.|Department of Medical Research, Yangon, Myanmar.
authors.forename: Myat Htut
authors.initials: MH
authors.lastname: Nyunt
authors.affiliation: Department of Obstetrics and Gynecology, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea.
authors.forename: Sunghun
authors.initials: S
authors.lastname: Na
authors.affiliation: Department of Molecular and Cellular Biochemistry, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea.
authors.forename: Kwon-Soo
authors.initials: KS
authors.lastname: Ha
authors.affiliation: Department of Internal Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea.
authors.forename: Seok-Ho
authors.initials: SH
authors.lastname: Hong
authors.affiliation: Department of Physiology, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea.
authors.forename: Won Sun
authors.initials: WS
authors.lastname: Park
authors.affiliation: Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
authors.forename: Jetsumon
authors.initials: J
authors.lastname: Sattabongkot
authors.affiliation: Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Ehime, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Tsuboi
authors.affiliation: Department of Medical Environmental Biology and Tropical Medicine, School of Medicine, Kangwon National University, Chuncheon, Gangwon-do, Republic of Korea.
authors.forename: Eun-Taek
authors.initials: ET
authors.lastname: Han
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D004912:Erythrocytes / Q000378:metabolism* / Q000469:parasitology; D015870:Gene Expression; D005822:Genetic Vectors / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D016778:Malaria, Falciparum / Q000469:parasitology; D016780:Malaria, Vivax / Q000469:parasitology; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D052940:Merozoites / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D010963:Plasmodium falciparum / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D010966:Plasmodium vivax / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D015800:Protozoan Proteins / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012156:Reticulocytes / Q000378:metabolism* / Q000469:parasitology; D052939:Schizonts / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D008565:Membrane Proteins; D020033:Protein Isoforms; D015800:Protozoan Proteins; C464927:RH4 protein, Plasmodium falciparum; D011994:Recombinant Proteins; C075483:reticulocyte-binding protein, Plasmodium vivax