Integration of multiple domains in a two-component sensor protein: the Bordetella pertussis BvgAS phosphorelay.
BvgS and BvgA, a two-component system, regulate virulence gene expression in Bordetella pertussis. BvgS is a transmembrane sensor protein that can autophosphorylate and phosphorylate BvgA. Phosphorylated BvgA activates transcription of virulence genes. The cytoplasmic region of BvgS contains three domains separated by alanine/proline-rich sequences--the transmitter, receiver and C-terminus. We report that the C-terminal domain, like the transmitter and receiver, is an essential part of the phosphorelay from BvgS to BvgA. The BvgS C-terminal domain is phosphorylated in trans via a phosphotransfer mechanism by the cytoplasmic portion of BvgS, and trans-phosphorylation of the C-terminal domain requires both the transmitter and receiver. We also demonstrate that phosphorylated, purified C-terminal domain alone is sufficient for phosphotransfer to BvgA. A point mutation in the C-terminal domain (His1172-->Gln) abolishes BvgS activity in vivo and eliminates detectable phosphorylation of BvgA in vitro. Activity of BvgS His 1172-->Gln could be restored by providing the wild-type C-terminal domain in trans. Our results indicate an obligatory role for an alternate phosphodonor module in the BvgAS phosphorelay.
Uhl
M A
MA
Department of Microbiology and Immunology, School of Medicine, University of California, Los Angeles 90024, USA.
Miller
J F
JF
D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D001886:Bordetella pertussis / Q000235:genetics / Q000378:metabolism* / Q000472:pathogenicity; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D015394:Molecular Structure; D016297:Mutagenesis, Site-Directed; D010766:Phosphorylation; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014774:Virulence / Q000235:genetics / Q000502:physiology
D001426:Bacterial Proteins; C065601:BvgA protein, Bacteria; D017931:DNA Primers; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; C489314:EvgA protein, E coli; D014157:Transcription Factors; C080662:bvgS protein, Bordetella pertussis