title: A T4SS Effector Targets Host Cell Alpha-Enolase Contributing toBrucella abortusIntracellular Lifestyle.
abstract: Brucella abortus, the causative agent of bovine brucellosis, invades and replicates within cells inside a membrane-bound compartment known as theBrucellacontaining vacuole (BCV). After trafficking along the endocytic and secretory pathways, BCVs mature into endoplasmic reticulum-derived compartments permissive for bacterial replication.BrucellaType IV Secretion System (VirB) is a major virulence factor essential for the biogenesis of the replicative organelle. Upon infection,Brucellauses the VirB system to translocate effector proteins from the BCV into the host cell cytoplasm. Although the functions of many translocated proteins remain unknown, some of them have been demonstrated to modulate host cell signaling pathways to favor intracellular survival and replication. BPE123 (BAB2_0123) is aB. abortusVirB-translocated effector protein recently identified by our group whose function is yet unknown. In an attempt to identify host cell proteins interacting with BPE123, a pull-down assay was performed and human alpha-enolase (ENO-1) was identified by LC/MS-MS as a potential interaction partner of BPE123. These results were confirmed by immunoprecipitation assays. In bone-marrow derived macrophages infected withB. abortus, ENO-1 associates to BCVs in a BPE123-dependent manner, indicating that interaction with translocated BPE123 is also occurring during the intracellular phase of the bacterium. Furthermore, ENO-1 depletion by siRNA impairedB. abortusintracellular replication in HeLa cells, confirming a role for α-enolase during the infection process. Indeed, ENO-1 activity levels were enhanced uponB. abortusinfection of THP-1 macrophagic cells, and this activation is highly dependent on BPE123. Taken together, these results suggest that interaction between BPE123 and host cell ENO-1 contributes to the intracellular lifestyle ofB. abortus.
authors.affiliation: Instituto de Investigaciones Biotecnológicas "Dr. Rodolfo A. Ugalde," Instituto Tecnológico de Chascomús, CONICET, Universidad Nacional de San Martín Buenos Aires, Argentina.
authors.forename: María I
authors.initials: MI
authors.lastname: Marchesini
authors.affiliation: Instituto de Investigaciones Biotecnológicas "Dr. Rodolfo A. Ugalde," Instituto Tecnológico de Chascomús, CONICET, Universidad Nacional de San Martín Buenos Aires, Argentina.
authors.forename: Susana M
authors.initials: SM
authors.lastname: Morrone Seijo
authors.affiliation: Instituto de Investigaciones Biotecnológicas "Dr. Rodolfo A. Ugalde," Instituto Tecnológico de Chascomús, CONICET, Universidad Nacional de San Martín Buenos Aires, Argentina.
authors.forename: Francisco F
authors.initials: FF
authors.lastname: Guaimas
authors.affiliation: Instituto de Investigaciones Biotecnológicas "Dr. Rodolfo A. Ugalde," Instituto Tecnológico de Chascomús, CONICET, Universidad Nacional de San MartínBuenos Aires, Argentina; Comisión Nacional de Energía Atómica, Grupo Pecuario, Centro Atómico EzeizaBuenos Aires, Argentina.
authors.forename: Diego J
authors.initials: DJ
authors.lastname: Comerci
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000302:isolation & purification / Q000378:metabolism*; D002003:Brucella abortus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism* / Q000502:physiology*; D002006:Brucellosis / Q000382:microbiology; D002470:Cell Survival; D003593:Cytoplasm / Q000378:metabolism / Q000382:microbiology; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000382:microbiology; D004926:Escherichia coli / Q000235:genetics; D006367:HeLa Cells; D054884:Host-Pathogen Interactions; D006801:Humans; D047468:Immunoprecipitation / Q000379:methods; D008019:Life Style; D008264:Macrophages / Q000382:microbiology; D051379:Mice; D018613:Microscopy, Confocal; D010751:Phosphopyruvate Hydratase / Q000302:isolation & purification / Q000378:metabolism*; D021381:Protein Transport; D034741:RNA, Small Interfering; D025521:Tumor Suppressor Proteins / Q000302:isolation & purification / Q000378:metabolism*; D000069319:Type IV Secretion Systems / Q000235:genetics / Q000378:metabolism*; D014617:Vacuoles / Q000382:microbiology; D037521:Virulence Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D014408:Biomarkers, Tumor; D004269:DNA, Bacterial; D004268:DNA-Binding Proteins; D034741:RNA, Small Interfering; D025521:Tumor Suppressor Proteins; D000069319:Type IV Secretion Systems; D037521:Virulence Factors; C095157:ENO1 protein, human; D010751:Phosphopyruvate Hydratase
keywords: Brucella abortus; Type IV secretion; alpha-enolase; effector; intracellular replication