PMID:15784571

Citation	Siboo, IR, Chambers, HF and Sullam, PM (2005) Role of SraP, a Serine-Rich Surface Protein of Staphylococcus aureus, in binding to human platelets. Infect. Immun. 73:2273-80
Abstract	The binding of bacteria to platelets is a postulated central event in the pathogenesis of infective endocarditis. Platelet binding by Streptococcus gordonii is mediated in large part by GspB, a high-molecular-mass cell wall glycoprotein. Although Staphylococcus aureus has a GspB homolog (SraP), little is known about its function. SraP has a calculated molecular mass of 227 kDa and, like GspB, is predicted to contain an atypical N-terminal signal sequence, two serine-rich repeat regions (srr1 and srr2) separated by a nonrepeat region, and a C-terminal cell wall anchoring motif (LPDTG). To assess whether SraP contributes to platelet binding, we compared the binding to human platelets of S. aureus strain ISP479C and of an isogenic variant (strain PS767) in which sraP had been disrupted by allelic replacement. Platelet binding in vitro by PS767 was 47% +/- 17% (mean +/- standard deviation) lower than that of ISP479C (P < 0.001). In addition, a recombinant fragment of SraP containing srr1 and the nonrepeat region was found to bind platelets directly. Binding was saturable, suggesting a receptor-ligand interaction. When tested in a rabbit model of endocarditis, in which each animal was simultaneously infected with ISP479C and PS767 at a ratio of approximately 1:1, the titers of the mutant strain within vegetations were significantly lower than those of the parent strain at 1 and 24 h postinfection. These results indicate that SraP can mediate the direct binding of S. aureus to platelets and that the platelet-binding domain of this glycoprotein is located within its N-terminal region. Moreover, the expression of SraP appears to be a virulence determinant in endovascular infection.
Links	PubMed PMC1087419 Online version:10.1128/IAI.73.4.2273-2280.2005
Keywords	Adhesins, Bacterial/physiology; Animals; Blood Platelets/metabolism; Endocarditis, Bacterial/etiology; Glycosylation; Humans; Rabbits; Staphylococcus aureus/pathogenicity; Transcription, Genetic; Virulence
edit table

Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
STAA8:SRAP		GO:0009277: cell wall	ECO:0000315:		C		Figure 2 shows that there is a high molecular mass protein in the ISP479C cell wall. The high molecular mass protein is said to be the SraP protein.	complete

References

See Help:References for how to manage references in GONUTS.