title: A Toll/IL-1R/resistance domain-containing thioredoxin regulates phagocytosis in Entamoeba histolytica.
abstract: BACKGROUND
  Entamoeba histolytica is a protozoan parasite that infects humans and causes amebiasis affecting developing countries. Phagocytosis of epithelial cells, erythrocytes, leucocytes, and commensal microbiota bacteria is a major pathogenic mechanism used by this parasite. A Toll/IL-1R/Resistance (TIR) domain-containing protein is required in phagocytosis in the social ameba Dictyostelium discoideum, an ameba closely related to Entamoeba histolytica in phylogeny. In insects and vertebrates, TIR domain-containing proteins regulate phagocytic and cell activation. Therefore, we investigated whether E. histolytica expresses TIR domain-containing molecules that may be involved in the phagocytosis of erythrocytes and bacteria.
  
  
  METHODS
  Using in silico analysis we explored in Entamoeba histolytica databases for TIR domain containing sequences. After silencing TIR domain containing sequences in trophozoites by siRNA we evaluated phagocytosis of erythrocytes and bacteria.
  
  
  RESULTS
  We identified an E. histolytica thioredoxin containing a TIR-like domain. The secondary and tertiary structure of this sequence exhibited structural similarity to TIR domain family. Thioredoxin transcripts silenced in E. histolytica trophozoites decreased erythrocytes and E. coli phagocytosis.
  
  
  CONCLUSIONS
  TIR domain-containing thioredoxin of E. histolytica could be an important element in erythrocytes and bacteria phagocytosis.
authors.affiliation: Medical Research Unit on Immunochemistry, Specialties Hospital, National Medical Centre Siglo XXI, Mexican Social Security Institute, Mexico City, Mexico.
authors.forename: Ismael
authors.initials: I
authors.lastname: Mancilla-Herrera
authors.forename: Alfonso
authors.initials: A
authors.lastname: Méndez-Tenorio
authors.forename: Isabel
authors.initials: I
authors.lastname: Wong-Baeza
authors.forename: Alexis P
authors.initials: AP
authors.lastname: Jiménez-Uribe
authors.forename: Marcela
authors.initials: M
authors.lastname: Alcántara-Hernández
authors.forename: Ramon
authors.initials: R
authors.lastname: Ocadiz-Ruiz
authors.forename: Mario A
authors.initials: MA
authors.lastname: Moreno-Eutimio
authors.forename: Lourdes A
authors.initials: LA
authors.lastname: Arriaga-Pizano
authors.forename: Constantino
authors.initials: C
authors.lastname: López-Macías
authors.forename: Jorge
authors.initials: J
authors.lastname: González-y-Merchand
authors.forename: Armando
authors.initials: A
authors.lastname: Isibasi
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019295:Computational Biology; D004748:Entamoeba histolytica / Q000235:genetics / Q000502:physiology*; D004912:Erythrocytes; D004926:Escherichia coli; D020868:Gene Silencing; D010587:Phagocytosis; D011487:Protein Conformation; D013879:Thioredoxins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; D013879:Thioredoxins