title: A dominant negative form of inositol 1,4,5-trisphosphate receptor induces metacyclogenesis and increases mitochondrial density in Trypanosoma cruzi.
abstract: Inositol 1,4,5-trisphosphate receptor (IP3R) is a key regulator of intracellular Ca(2+) concentration that release Ca(2+) from Ca(2+) stores in response to various external stimuli. IP3R also works as a signal hub which form a platform for interacting with various proteins involved in diverse cell signaling. Previously, we have identified an IP3R homolog in the parasitic protist, Trypanosoma cruzi (TcIP3R). Parasites expressing reduced or increased levels of TcIP3R displayed defects in growth, transformation, and infectivity. In the present study, we established parasitic strains expressing a dominant negative form of TcIP3R, named DN-TcIP3R, to further investigate the physiological role(s) of TcIP3R. We found that the growth of epimastigotes expressing DN-TcIP3R was significantly slower than that of parasites with TcIP3R expression levels that were approximately 65% of wild-type levels. The expression of DN-TcIP3R in epimastigotes induced metacyclogenesis even in the normal growth medium. Furthermore, these epimastigotes showed the presence of dense mitochondria under a transmission electron microscope. Our findings confirm that TcIP3R is crucial for epimastigote growth, as previously reported. They also suggest that a strong inhibition of the IP3R-mediated signaling induces metacyclogenesis and that mitochondrial integrity is closely associated with this signaling.
authors.affiliation: Department of Molecular and Cellular Parasitology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan. Electronic address: muneaki@juntendo.ac.jp.
authors.forename: Muneaki
authors.initials: M
authors.lastname: Hashimoto
authors.affiliation: Department of Molecular and Cellular Parasitology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan. Electronic address: tnara@juntendo.ac.jp.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nara
authors.affiliation: Laboratory for Developmental Neurobiology, RIKEN Brain Science Institute, Saitama, 351-0198, Japan; Princess Margaret Cancer Centre, Department of Medical Biophysics, University of Toronto, M5G1L7, Toronto, Ontario, Canada. Electronic address: menomoto@uhnres.utoronto.ca.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Enomoto
authors.affiliation: Department of Pharmacology, Juntendo University School of Medicine, Bunkyo-ku, Tokyo, 113-8421, Japan. Electronic address: nagomik@juntendo.ac.jp.
authors.forename: Nagomi
authors.initials: N
authors.lastname: Kurebayashi
authors.affiliation: Laboratoly of Morphology and Image Analysis, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan. Electronic address: myoshida@juntendo.ac.jp.
authors.forename: Mitsutaka
authors.initials: M
authors.lastname: Yoshida
authors.affiliation: Department of Pharmacology, Juntendo University School of Medicine, Bunkyo-ku, Tokyo, 113-8421, Japan. Electronic address: tsakurai@juntendo.ac.jp.
authors.forename: Takashi
authors.initials: T
authors.lastname: Sakurai
authors.affiliation: Department of Molecular and Cellular Parasitology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan. Electronic address: tmita@juntendo.ac.jp.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Mita
authors.affiliation: Laboratory for Developmental Neurobiology, RIKEN Brain Science Institute, Saitama, 351-0198, Japan; Calcium Oscillation Project, International Cooperative Research Project and Solution-Oriented Research for Science and Technology, Japan Science and Technology Agency, Kawaguchi, Saitama, 332-0012, Japan. Electronic address: mikosiba@brain.riken.jp.
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Mikoshiba
mesh_terms: D000818:Animals; D001896:Boron Compounds / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental; D017125:Genes, Protozoan; D053496:Inositol 1,4,5-Trisphosphate Receptors / Q000235:genetics* / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D015800:Protozoan Proteins / Q000235:genetics* / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016053:RNA, Protozoan / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D014349:Trypanosoma cruzi / Q000235:genetics* / Q000378:metabolism* / Q000472:pathogenicity
chemical_list: C538758:2-aminoethyl diphenylborinate; D001896:Boron Compounds; D053496:Inositol 1,4,5-Trisphosphate Receptors; D015800:Protozoan Proteins; D012333:RNA, Messenger; D016053:RNA, Protozoan
keywords: Ca(2+) signaling; Inositol 1,4,5-trisphosphate receptor; Metacyclogenesis; Mitochondria; Trypanosoma cruzi