Regulation of Brucella virulence by the two-component system BvrR/BvrS.
The Brucella BvrR/BvrS two-component regulatory system is highly similar to the regulatory and sensory proteins of Sinorhizobium and Agrobacterium necessary for endosymbiosis and pathogenicity in plants, and very similar to a putative system present in the animal pathogen Bartonella. Mutations in the bvrR or bvrS genes hamper the penetration of B. abortus in non-phagocytic cells and impairs intracellular trafficking and virulence. In contrast to virulent Brucella, BvrR/BvrS mutants do not recruit small GTPases of the Rho subfamily required for actin polymerization and penetration to cells. Dysfunction of the BvrR/BvrS system alters the outer membrane permeability, the expression of several group 3 outer membrane proteins and the pattern of lipid A acylation. Constructs of virulent B. abortus chimeras containing heterologous LPS from the bvrS(-) mutant demonstrated an altered permeability to cationic peptides similar to that of the BvrR/BvrS mutants. We hypothesize that the Brucella BvrR/BvrS is a system devoted to the homeostasis of the outer membrane and, therefore in the interface for cell invasion and mounting the required structures for intracellular parasitism.
López-Goñi
I
I
Departamento de Microbiología, Universidad de Navarra, C/lrunlarrea no 1, Pamplona 31008, Spain. ilgoni@unav.es
Guzmán-Verri
C
C
Manterola
L
L
Sola-Landa
A
A
Moriyón
I
I
Moreno
E
E
D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics*; D001428:Bacterial Vaccines; D002002:Brucella / Q000235:genetics* / Q000276:immunology / Q000472:pathogenicity*; D020558:GTP Phosphohydrolases / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D016296:Mutagenesis; D011487:Protein Conformation; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014774:Virulence
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D001428:Bacterial Vaccines; C471339:BvrR protein, Brucella; C471340:BvrS protein, Brucella; D020558:GTP Phosphohydrolases