title: Rab32 is essential for maintaining functional acidocalcisomes, and for growth and infectivity of Trypanosoma cruzi.
abstract: The contractile vacuole complex (CVC) of Trypanosoma cruzi, the etiologic agent of Chagas disease, collects and expels excess water as a mechanism of regulatory volume decrease after hyposmotic stress; it also has a role in cell shrinking after hyperosmotic stress. Here, we report that, in addition to its role in osmoregulation, the CVC of T. cruzi has a role in the biogenesis of acidocalcisomes. Expression of dominant-negative mutants of the CVC-located small GTPase Rab32 (TcCLB.506289.80) results in lower numbers of less-electron-dense acidocalcisomes, lower content of polyphosphate, lower capacity for acidocalcisome acidification and Ca(2+) uptake that is driven by the vacuolar proton pyrophosphatase and the Ca(2+)-ATPase, respectively, as well as less-infective parasites, revealing the role of this organelle in parasite infectivity. By using fluorescence, electron microscopy and electron tomography analyses, we provide further evidence of the active contact of acidocalcisomes with the CVC, indicating an active exchange of proteins between the two organelles.
authors.affiliation: Department of Cellular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA.
authors.forename: Sayantanee
authors.initials: S
authors.lastname: Niyogi
authors.affiliation: Department of Cellular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA.
authors.forename: Veronica
authors.initials: V
authors.lastname: Jimenez
authors.affiliation: Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho and Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens - Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil.
authors.forename: Wendell
authors.initials: W
authors.lastname: Girard-Dias
authors.affiliation: Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho and Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens - Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil Diretoria de Metrologia Aplicada a Ciências da Vida, Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMETRO), Xerém, Rio de Janeiro 25250-020, Brazil.
authors.forename: Wanderley
authors.initials: W
authors.lastname: de Souza
authors.affiliation: Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho and Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens - Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil Diretoria de Metrologia Aplicada a Ciências da Vida, Instituto Nacional de Metrologia, Qualidade e Tecnologia (INMETRO), Xerém, Rio de Janeiro 25250-020, Brazil.
authors.forename: Kildare
authors.initials: K
authors.lastname: Miranda
authors.affiliation: Department of Cellular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA rdocampo@uga.edu.
authors.forename: Roberto
authors.initials: R
authors.lastname: Docampo
mesh_terms: D000143:Acids / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D014355:Chagas Disease / Q000469:parasitology*; D002522:Chlorocebus aethiops; D005347:Fibroblasts / Q000166:cytology / Q000469:parasitology; D005455:Fluorescent Antibody Technique; D052816:Foreskin / Q000166:cytology; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D008854:Microscopy, Electron; D032446:Myoblasts / Q000166:cytology / Q000469:parasitology; D015388:Organelles / Q000378:metabolism*; D064587:Osmoregulation / Q000502:physiology; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014349:Trypanosoma cruzi / Q000472:pathogenicity*; D014617:Vacuoles / Q000378:metabolism; D014709:Vero Cells; D014882:Water-Electrolyte Balance
chemical_list: D000143:Acids; D015800:Protozoan Proteins; D012333:RNA, Messenger; D002118:Calcium
keywords: Acidocalcisome; Calcium; Contractile vacuole; Polyphosphate; Vacuolar pyrophosphatase