title: Giant FAZ10 is required for flagellum attachment zone stabilization and furrow positioning inTrypanosoma brucei.
abstract: The flagellum and flagellum attachment zone (FAZ) are important cytoskeletal structures in trypanosomatids, being required for motility, cell division and cell morphogenesis. Trypanosomatid cytoskeletons contain abundant high molecular mass proteins (HMMPs), but many of their biological functions are still unclear. Here, we report the characterization of the giant FAZ protein, FAZ10, inTrypanosoma brucei, which, using immunoelectron microscopy, we show localizes to the intermembrane staples in the FAZ intracellular domain. Our data show that FAZ10 is a giant cytoskeletal protein essential for normal growth and morphology in both procyclic and bloodstream parasite life cycle stages, with its depletion leading to defects in cell morphogenesis, flagellum attachment, and kinetoplast and nucleus positioning. We show that the flagellum attachment defects are probably brought about by reduced tethering of the proximal domain of the paraflagellar rod to the FAZ filament. Further, FAZ10 depletion also reduces abundance of FAZ flagellum domain protein, ClpGM6. Moreover, ablation of FAZ10 impaired the timing and placement of the cleavage furrow during cytokinesis, resulting in premature or asymmetrical cell division.
authors.affiliation: Department of Cellular and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, Brazil.
authors.forename: Bernardo P
authors.identifier: 0000-0001-5266-5336
authors.initials: BP
authors.lastname: Moreira
authors.affiliation: Department of Cellular and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, Brazil.
authors.forename: Carol K
authors.initials: CK
authors.lastname: Fonseca
authors.affiliation: Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
authors.forename: Tansy C
authors.identifier: 0000-0002-0799-6600
authors.initials: TC
authors.lastname: Hammarton
authors.affiliation: Department of Cellular and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto 14049-900, Brazil munira@fmrp.usp.br.
authors.forename: Munira M A
authors.identifier: 0000-0002-7945-2899
authors.initials: MM
authors.lastname: Baqui
mesh_terms: D002467:Cell Nucleus / Q000378:metabolism; D049109:Cell Proliferation; D045584:Chromosome Positioning; D020090:Chromosome Segregation; D048749:Cytokinesis; D003598:Cytoskeletal Proteins / Q000378:metabolism; D005407:Flagella / Q000378:metabolism* / Q000648:ultrastructure; D055785:Gene Knockdown Techniques; D015800:Protozoan Proteins / Q000378:metabolism*; D014346:Trypanosoma brucei brucei / Q000166:cytology* / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D003598:Cytoskeletal Proteins; D015800:Protozoan Proteins
keywords: Cytokinesis; Cytoskeleton; FAZ; FAZ10; Giant protein; Kinetoplast positioning; Nucleus positioning