title: YscP of Yersinia pestis is a secreted component of the Yop secretion system.
abstract: The Yersinia pestis low-Ca2+ response stimulon is responsible for the environmentally regulated expression and secretion of antihost proteins (V antigen and Yops). We have previously shown that yscO encodes a secreted core component of the Yop secretion (Ysc) mechanism. In this study, we constructed and characterized in-frame deletions in the adjacent gene, yscP, in the yscN-yscU operon. The DeltaP1 mutation, which removed amino acids 246 to 333 of YscP, had no effect on Yop expression or secretion, and the mutant protein, YscP1, was secreted, as was YscP in the parent. In contrast, the DeltaP2 strain expressed and secreted less of each Yop than did the parent under the inductive conditions of 37 degrees C and the absence of Ca2+, with an exception being YopE, which was only minimally affected by the mutation. The YscP2 protein, missing amino acids 57 to 324 of YscP, was expressed but not secreted by the DeltaP2 mutant. The effect of the DeltaP2 mutation was at the level of Yop secretion because YopM and V antigen still showed limited secretion when overproduced in trans. Excess YscP also affected secretion: overexpression of YscP in the parent, in either yscP mutant, or in an lcrG mutant effectively shut off secretion. However, co-overexpression of YscO and YscP had no effect on secretion, and YscP overexpression in an lcrE mutant had little effect on Yop secretion, suggesting that YscP acts, in conjunction with YscO, at the level of secretion control of LcrE at the bacterial surface. These findings place YscP among the growing family of mobile Ysc components that both affect secretion and themselves are secreted by the Ysc.
authors.affiliation: Department of Microbiology and Immunology, Albert B. Chandler Medical Center, University of Kentucky, Lexington, Kentucky 40536-0084, USA.
authors.forename: P L
authors.initials: PL
authors.lastname: Payne
authors.forename: S C
authors.initials: SC
authors.lastname: Straley
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000378:metabolism; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D020013:Calcium Signaling / Q000235:genetics*; D002458:Cell Fractionation; D004926:Escherichia coli / Q000235:genetics; D018628:Gene Dosage; D015870:Gene Expression; D005816:Genetic Complementation Test; D008565:Membrane Proteins; D051379:Mice; D016296:Mutagenesis; D010641:Phenotype; D010957:Plasmids; D052899:Pore Forming Cytotoxic Proteins; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011994:Recombinant Proteins / Q000378:metabolism; D013045:Species Specificity; D015010:Yersinia pestis / Q000235:genetics / Q000472:pathogenicity*
chemical_list: D000942:Antigens, Bacterial; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; C043908:LcrV protein, Yersinia; D008565:Membrane Proteins; D052899:Pore Forming Cytotoxic Proteins; D011994:Recombinant Proteins; C118802:Yop proteins translocation protein P, Yersinia; C060772:yopM protein, Yersinia