Asp3 mediates multiple protein-protein interactions within the accessory Sec system of Streptococcus gordonii.
Bacterial binding to human platelets is an important step in the pathogenesis of infective endocarditis. Streptococcus gordonii can mediate its platelet attachment through a cell wall glycoprotein termed GspB ('gordonii surface protein B'). GspB export is mediated by a seven-component accessory Sec system, containing two homologues of the general secretory pathway (SecA2 and SecY2) and five accessory Sec proteins (Asps1-5). Here we show that the Asps are required for optimal export of GspB independent of the glycosylation process. Furthermore, yeast two-hybrid screening of the accessory Sec system revealed interactions occurring between Asp3 and the other components of the system. Asp3 was shown to bind SecA2, Asp1, Asp2 and itself. Mutagenesis of Asp3 identified N- and C-terminal regions that are essential for GspB transport, and conserved residues within the C-terminal domain mediated Asp3 binding to other accessory Sec components. The loss of binding by Asp3 also resulted in an impaired ability of S. gordonii to secrete GspB. These studies indicate that Asp3 is a central element mediating multiple interactions among accessory Sec components that are essential for GspB transport to the cell surface.
Seepersaud
Ravin
R
San Francisco Veteran Affairs Medical Center, University of California, San Francisco, CA 94121, USA.
Bensing
Barbara A
BA
Yen
Yihfen T
YT
Sullam
Paul M
PM
D000595:Amino Acid Sequence; D001422:Bacterial Adhesion; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D054643:INDEL Mutation; D008969:Molecular Sequence Data; D025941:Protein Interaction Mapping; D021381:Protein Transport; D054773:Streptococcus gordonii / Q000235:genetics* / Q000378:metabolism
D001426:Bacterial Proteins
Mol Microbiol. 2002 May;44(4):1081-94
12010500
Plasmid. 2000 Sep;44(2):183-90
10964628
J Bacteriol. 2009 Jun;191(11):3482-91
19363114
Mol Microbiol. 2005 Dec;58(5):1468-81
16313630
Microb Pathog. 2008 Oct;45(4):297-301
18656529
EMBO J. 1997 Oct 15;16(20):6105-13
9321390
Microbiology (Reading). 2006 Apr;152(Pt 4):1029-1040
16549667
J Bacteriol. 2004 Feb;186(3):638-45
14729688
J Bacteriol. 2005 Jun;187(11):3878-83
15901716
J Bacteriol. 2008 Sep;190(18):6188-96
18621893
Infect Immun. 2005 Oct;73(10):6629-38
16177339
Mol Microbiol. 2005 Oct;58(2):380-92
16194227
Proc Natl Acad Sci U S A. 1994 May 10;91(10):4539-43
8183945
Proc Natl Acad Sci U S A. 1996 Apr 30;93(9):4131-6
8633028
Br J Haematol. 2005 Apr;129(1):101-9
15801962
Curr Opin Cell Biol. 2000 Aug;12(4):420-30
10873830
Curr Opin Struct Biol. 2004 Aug;14(4):390-6
15313231
Mol Microbiol. 2005 Sep;57(6):1653-63
16135231
Infect Immun. 1987 Aug;55(8):1743-50
3112008
Nature. 2002 Aug 8;418(6898):662-5
12167867
Mol Microbiol. 2008 Dec;70(5):1094-104
18826412
Mol Microbiol. 2005 Oct;58(2):349-57
16194224
Mol Cell Proteomics. 2005 Jun;4(6):819-26
15781424
Oral Microbiol Immunol. 2008 Feb;23(1):70-8
18173801
EMBO J. 1989 Sep;8(9):2703-9
2531087
J Bacteriol. 2004 Nov;186(21):7100-11
15489421
Biochim Biophys Acta. 2004 Nov 11;1694(1-3):81-95
15546659
Mol Microbiol. 2004 Apr;52(1):189-203
15049820
Annu Rev Biochem. 2008;77:643-67
18078384
Infect Immun. 2004 Nov;72(11):6528-37
15501784
J Bacteriol. 2005 Oct;187(19):6852-5
16166550
Nature. 2006 Nov 30;444(7119):567-73
17136086
Cell Stress Chaperones. 2000 Oct;5(4):267-75
11048650
J Bacteriol. 2007 May;189(10):3846-54
17369296
Cell Microbiol. 2004 Sep;6(9):805-16
15272862
J Infect Dis. 2008 Aug 1;198(3):375-83
18507531
Genes Dev. 2001 Jul 15;15(14):1725-52
11459823
Infect Immun. 2006 Mar;74(3):1933-40
16495569
Mol Microbiol. 2007 May;64(3):844-57
17462028
Biochim Biophys Acta. 2007 Jan;1768(1):5-12
17011510
Nature. 2008 Oct 16;455(7215):936-43
18923516