title: The cytostome-cytopharynx complex of Trypanosoma cruzi epimastigotes disassembles during cell division.
abstract: The cytostome-cytopharynx complex is the main site for endocytosis in epimastigotes of Trypanosoma cruzi It consists of an opening at the plasma membrane surface - the cytostome - followed by a membrane invagination - the cytopharynx. In G1/S cells, this structure is associated with two specific sets of microtubules, a quartet and a triplet. Here, we used electron microscopy and electron tomography to build 3D models of the complex at different stages of the cell cycle. The cytostome-cytopharynx is absent in late G2 and M phase cells, whereas early G2 cells have either a short cytopharynx or no visible complex, with numerous vesicles aligned to the cytostome-cytopharynx microtubules. The microtubule quartet remains visible throughout cell division (albeit in a shorter form), and is duplicated during G2/M. In contrast, the microtubule triplet is absent during late G2/M. Cells in cytokinesis have an invagination of the flagellar pocket membrane likely to represent early stages in cytostome-cytopharynx assembly. Cells in late cytokinesis have two fully developed cytostome-cytopharynx complexes. Our data suggest that the microtubule quartet serves as a guide for new cytostome-cytopharynx assembly.
authors.affiliation: Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil.|Núcleo de Biologia Estrutural e Bioimagens (CENABIO), Rio de Janeiro 21941-902, Brazil.
authors.forename: Carolina de L
authors.initials: CL
authors.lastname: Alcantara
authors.affiliation: Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil.|Núcleo de Biologia Estrutural e Bioimagens (CENABIO), Rio de Janeiro 21941-902, Brazil.
authors.forename: Juliana C
authors.initials: JC
authors.lastname: Vidal
authors.affiliation: Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil.|Núcleo de Biologia Estrutural e Bioimagens (CENABIO), Rio de Janeiro 21941-902, Brazil.
authors.forename: Wanderley
authors.initials: W
authors.lastname: de Souza
authors.affiliation: Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-902, Brazil narcisa@biof.ufrj.br.|Núcleo de Biologia Estrutural e Bioimagens (CENABIO), Rio de Janeiro 21941-902, Brazil.
authors.forename: Narcisa L
authors.identifier: 0000-0003-4863-4945
authors.initials: NL
authors.lastname: Cunha-E-Silva
mesh_terms: D002455:Cell Division; D048749:Cytokinesis; D005407:Flagella / Q000378:metabolism / Q000648:ultrastructure; D016195:G2 Phase; D008018:Life Cycle Stages; D008677:Metaphase; D008870:Microtubules / Q000378:metabolism / Q000648:ultrastructure; D008954:Models, Biological; D014349:Trypanosoma cruzi / Q000166:cytology* / Q000254:growth & development* / Q000648:ultrastructure
keywords: Cell cycle; Cytostome; Tridimensional reconstruction; Trypanosoma cruzi