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Infection and Immunity, February 2002, p. 993-997, Vol. 70, No. 2
0019-9567/01/$04.00+0 DOI: 70.2.993-997.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.
Novel Laminin-Binding Protein of Streptococcus pyogenes, Lbp, Is Involved in Adhesion to Epithelial Cells
Yutaka Terao, Shigetada Kawabata,* Eiji Kunitomo, Ichiro Nakagawa, and Shigeyuki Hamada
Department of Oral Microbiology, Osaka University Faculty of Dentistry, Suita-Osaka 565-0871, Japan
Received 26 July 2001/
Returned for modification 25 August 2001/
Accepted 8 November 2001

ABSTRACT
The
lbp gene, which encodes a laminin-binding protein (Lbp)
of
Streptococcus pyogenes, was found in all
S. pyogenes M types.
An Lbp-deficient mutant showed a significantly lower efficiency
of adhesion to HEp-2 cells than did the wild-type strain. These
results indicate that Lbp is one of the important
S. pyogenes adhesins.

INTRODUCTION
Streptococcus pyogenes (group A streptococcus) is a gram-positive
pathogenic bacterium that causes pharyngitis, impetigo, scarlet
fever, and streptococcal toxic shock-like syndrome (TSLS) (
23).
These diseases are initiated by the adhesion of
S. pyogenes to epithelial cells in the upper respiratory tract or skin.
In the process of adhesion, extracellular matrix proteins such
as fibronectin (Fn) and laminin (Lm) serve as mediators between
the bacteria and host cells (
2,
3). Previous studies have demonstrated
that Fn-binding proteins of
S. pyogenes, including protein F1/SfbI
(
21,
26), protein F2 (
9), SfbII (
15), FBP54 (
1), PFBP (
19),
and Fba (
28), function as adhesins and invasins.
S. pyogenes has been reported to bind to Lm (
25); however, its Lm-binding
protein has not been identified, although Hytönen et al.
recently suggested that the Lm-binding activity of
S. pyogenes is mediated by SpeB (
8).
Several streptococcal strains possess Fn-binding proteins and other adhesins (10-13), which are present in membrane- or cell-associated form. These proteins are linked either to the bacterial cell wall with the C-terminal region harboring an LPXTG motif (5, 20) or to the cell membrane with the N-terminal region harboring an LXXC or XXGC motif (24). Recently, the complete genome sequence of S. pyogenes strain SF370 (M type 1) has been deposited in the GenBank database (accession number AE004092) (4). Using this genome database, we found a novel open reading frame (ORF) containing the XXGC motif in the N-terminal region. These typical sequences are known as the signal peptidase II cleavage site of cell surface lipoprotein (12, 16, 22). In this report, we identify a novel gene encoding a cell surface protein and characterize the role of this protein in bacterial adhesion.

ORF analysis of the complete genome sequence.
The bacterial strains and plasmids used in this study are described
in Table
1.
Based on the complete genome sequence of
S. pyogenes,
the putative ORF sequences were translated into amino acid sequences
with the help of GeneWorks software (IntelliGenetics, Campbell,
Calif.). When we searched for genes harboring an XXGC motif
in the N terminus, one ORF was found and designated
lbp (the
gene encoding the Lm-binding protein of group A streptococci).
The nucleotide sequences of strains SSI-9 (M1) and SSI-1 (M3)
were then determined by using an ABI PRISM 310 DNA sequencer
(PE Applied Biosystems, Foster City, Calif.), and sequencing
reactions were performed by the Sanger dideoxy-chain termination
method. The
lbp gene was found to consist of 921 nucleotides
and encode a protein of 306 amino acids (designated Lbp) with
a calculated molecular mass of

34.1 kDa. A putative signal peptidase
cleavage site was revealed between amino acids 16 and 17 in
the N-terminal region by using a method described previously
(
29). An alignment analysis of the deduced amino acid sequences
of Lbp from strains SSI-9 (M1), SF370 (M1) (
4), and SSI-1 (M3)
showed that Lbp is 100% conserved. The high degree of similarity
(98%) seen between Lbp and the Lm-binding protein of
S. agalactiae,
Lmb (
22), strongly indicates that Lbp possesses Lm-binding activity.

Distribution of lbp among streptococci.
The distribution of
lbp among a variety of streptococcal species
was examined by Southern hybridization using
lbp as a probe.
Chromosomal DNA samples were digested with
EcoRI and subjected
to hybridization. Lbp was detected in strains M1, -2, -3, -4,
-6, -12, -18, -22, -28, and -49 of
S. pyogenes, as well as in
some group B, C, D, and G strains (Fig.
1).
Furthermore, an
lbp-specific PCR analysis of various strains demonstrated that
lbp is found in all M type strains of
S. pyogenes (data not
shown); however,
lbp was not detected in oral streptococci.

Lbp is a novel Lm-binding protein of S. pyogenes.
To determine whether Lbp possesses Lm-binding ability, recombinant
Lbp (rLbp) was purified from the cell lysate of
Escherichia coli BL21 harboring pYT1097 (Fig.
2A)
by using glutathione Sepharose
4B affinity chromatography, followed by sodium dodecyl sulfate-polyacrylamide
gel electrophoresis (SDS-PAGE) (Fig.
2B). rLbp, glutathione
S-transferase (GST), and 8 M urea extracts of
S. pyogenes were
subjected to SDS-PAGE and then transferred to a polyvinylidene
difluoride (PVDF) membrane, after which the membrane was incubated
with 100 µg of biotinylated human Lm (Life Technology,
Rockville, Md.) per ml. Biotinylated human Lm was prepared with
an ECL protein biotinylation module (Amersham Pharmacia Biotech,
Uppsala, Sweden). Lbp reacted with human Lm but not with GST,
streptavidin only (Fig.
2B and
3B),
Fn, or immunoglobulins (data
not shown).
To investigate the function of Lbp, mutant strain TR-7 (
lbp)
was prepared as described below. The PCR product of an internal
portion of
lbp was ligated into a pGEM-T Easy vector (Promega,
Madison, Wis.) and then digested with
EcoRI, after which the
fragments were cloned into vector pSF151 (
27). The resultant
plasmid, pYT1088, was transformed into strain SSI-9 by electroporation
(Fig.
3A). Introduction of pYT1088 resulted in mutant strain
TR-7 (
lbp), which did not react with rabbit anti-Lbp antibody
(data not shown). The 8 M urea extracts of strains SSI-9 (wild
type) and TR-7 (
lbp) were found to contain a 28-kDa Lm-binding
protein (Fig.
3B). A recent report by Hytönen et al. (
8)
has indicated that SpeB is not only secreted from but also binds
to bacterial cell surfaces and that the 28-kDa mature SpeB protein
may mediate Lm binding. Furthermore, another 34-kDa Lm-binding
protein (Lbp) was found in the extract of strain SSI-9 (Fig.
3B), while other, unknown, components (20 and 15 kDa) were shown
to bind to Lm. These results clearly indicated that Lbp is a
novel Lm-binding protein of
S. pyogenes. Since 8 M urea extraction
is a useful method by which to extract bacterial cell surface-associated
proteins (
6), cellular extracts of
S. pyogenes in 8 M urea were
used for Western blot analysis. Based on the results demonstrated
in Fig.
2C and
3B, we speculated that Lbp is expressed on the
cell surface of
S. pyogenes. This organism expresses a variety
of cell surface proteins with a specific ligand. Therefore,
it may be hypothesized that Lbp eventually accelerates the infection
of
S. pyogenes by its binding to Lm in the underlying tissues
once the organism adheres to and invades host cells.

Role of Lbp in cell adhesion of S. pyogenes.
To investigate the role of Lbp of
S. pyogenes, the adhesion
and invasion efficiencies of Lbp-deficient mutant strain TR-7
were compared with those of parent strain SSI-9. Streptococcal
adherence and invasion assays were performed as previously described
(
14). The TR-7 mutant demonstrated a significantly lower level
of adhesion than wild-type strain SSI-9 (Fig.
4A;
P < 0.005);
however, the TR-7 mutant invaded HEp-2 cells as efficiently
as did strain SSI-9 (Fig.
4B). These results suggest that Lbp
works as an adhesin but not as an invasin.
The
mga,
emm,
sic, and
scpA genes are known as members of the
mga regulon. The
fba and
lbp genes are located downstream of
the
scpA gene in type M1
S. pyogenes. We investigated the transcriptional
level of the
mga mutant by reverse transcription-PCR analysis;
however, transcriptional levels of
mga-,
emm-,
sic-,
scpA-,
and
fba-specific mRNAs were not detected in the
mga mutant,
although the
lbp gene was not influenced (
28). Furthermore,
we found putative promoter sequences (-35 and -10), a ribosome-binding
recognition site, and two pairs of inverted repeats as putative
transcriptional terminators in the nucleotide sequence between
the
fba gene and the
lbp gene. These findings suggested that
the
fba gene is a member of the
mga regulon and that the expression
of
lbp mRNA is not controlled by the Mga regulator.
Common and highly conserved cell surface proteins for a protective antigen are highly regarded as an ideal vaccine against infection by S. pyogenes. In this regard, Fn-binding proteins were considered good candidates as a universal vaccine; however, a previous report showed that protein F1 was not present in the M1 and M3 strains among many M types of S. pyogenes (18). Our own recent study (28) has revealed that another Fn-binding protein, Fba, is expressed in M1, -2, and -4 and several other types but not in M3. M1 and M3 are the most common serotypes isolated from patients with TSLS and severe invasive diseases (17). There are more than 90 serotypes of the M protein, and protective antibodies are type specific (7). The results of the present study suggest the possibility that Lbp functions as a protective antigen against M1 and M3, as well as several other major serotypes of S. pyogenes. If Lbp could be an effective antigen, it might be useful as a universal vaccine against infection by a wide variety of S. pyogenes M types.

Nucleotide sequence accession number.
The sequence of the
lbp gene was deposited in DDBJ/EMBL/GenBank
under accession number
AB040535.

ACKNOWLEDGMENTS
This work was supported by grants from the Japan Society for
Promotion of Science and the Ministry of Health, Labor and Welfare
of Japan.

FOOTNOTES
* Corresponding author. Mailing address: Department of Oral Microbiology, Osaka University Faculty of Dentistry, 1-8, Yamadaoka, Suita-Osaka 565-0871, Japan. Phone: 81-6-6879-2898. Fax: 81-6-6878-4755. E-mail:
kawabata{at}0040dent.osaka-u.ac.jp.

Editor: E. I. Tuomanen

REFERENCES
1
- Courtney, H. S., Y. Li, J. B. Dale, and D. L. Hasty. 1994. Cloning, sequencing, and expression of a fibronectin/fibrinogen-binding protein from group A streptococci. Infect. Immun. 62:3937-3946.[Abstract/Free Full Text]
2
- Cue, D., P. E. Dombek, H. Lam, and P. P. Cleary. 1998. Streptococcus pyogenes serotype M1 encodes multiple pathways for entry into human epithelial cells. Infect. Immun. 66:4593-4601.[Abstract/Free Full Text]
3
- Cue, D., S. O. Southern, P. J. Southern, J. Prabhakar, W. Lorelli, J. M. Smallheer, S. A. Mousa, and P. P. Cleary. 2000. A nonpeptide integrin antagonist can inhibit epithelial cell ingestion of Streptococcus pyogenes by blocking formation of integrin
5ß1-fibronectin-M1 protein complexes. Proc. Natl. Acad. Sci. USA 97:2858-2863.[Abstract/Free Full Text]
4
- Ferretti, J. J., W. M. McShan, D. Ajdic, D. J. Savic, G. Savic, K. Lyon, C. Primeaux, S. Sezate, A. N. Suvorov, S. Kenton, H. S. Lai, S. P. Lin, Y. Qian, H. G. Jia, F. Z. Najar, Q. Ren, H. Zhu, L. Song, J. White, X. Yuan, S. W. Clifton, B. A. Roe, and R. Mclaughlin. 2001. Complete genome sequence of an M1 strain of Streptococcus pyogenes. Proc. Natl. Acad. Sci. USA 98:4658-4663.[Abstract/Free Full Text]
5
- Fischetti, V. A., V. Pancholi, and O. Schneewind. 1990. Conservation of a hexapeptide sequence in the anchor region of surface proteins from Gram-positive cocci. Mol. Microbiol. 4:1603-1605.[Medline]
6
- Hamada, S., T. Horikoshi, T. Minami, S. Kawabata, J. Hiraoka, T. Fujiwara, and T. Ooshima. 1991. Oral passive immunization against dental caries in rats by use of hen egg yolk antibodies specific for cell-associated glucosyltransferase of Streptococcus mutans. Infect. Immun. 59:4161-4167.[Abstract/Free Full Text]
7
- Hoe, N., D. K. Nakashima, D. Grigsby, X. Pan, S. J. Dou, S. Naidich, M. Garcia, E. Kahn, D. Bergmire-Sweat, and J. M. Musser. 1999. Rapid molecular genetic subtyping of serotype M1 group A streptococcus strains. Emerg. Infect. Dis. 5:254-263.[Medline]
8
- Hytönen, J., S. Haataja, D. Gerlach, A. Podobielski, and J. Finne. 2001. The SpeB virulence factor of Streptococcus pyogenes, a multifunctional secreted and cell surface molecule with strepadhesin, laminin-binding and cysteine protease activity. Mol. Microbiol. 39:512-519.[CrossRef][Medline]
9
- Jaffe, J., S. Natanson-Yaron. M. G. Caparon, and E. Hanski. 1996. Protein F2, a novel fibronectin-binding protein from Streptococcus pyogenes, possesses two binding domains. Mol. Microbiol. 21:373-384.[CrossRef][Medline]
10
- Jenkinson, H. F., and R. J. Lamont. 1997. Streptococcal adhesion and colonization. Crit. Rev. Oral Biol. Med. 8:175-200.[Abstract/Free Full Text]
11
- Jenkinson, H. F. 1994. Cell surface protein receptors in oral streptococci. FEMS Microbiol. Lett. 121:133-140.[CrossRef][Medline]
12
- Jenkinson, H. F. 1992. Adherence, coaggregation, and hydrophobicity of Streptococcus gordonii associated with expression of cell surface lipoproteins. Infect. Immun. 60:1225-1228.[Abstract/Free Full Text]
13
- Joh, D., P. Speziale, S. Gurusiddappa, J. Manor, and M. Höök. 1998. Multiple specificities of staphylococcal and streptococcal fibronectin-binding microbial surface components recognizing adhesive matrix molecules. Eur. J. Biochem. 258:897-905.[Medline]
14
- Kawabata, S., H. Kuwata, I. Nakagawa, S. Morimatsu, K. Sano, and S. Hamada. 1999. Capsular hyaluronic acid of group A streptococci hampers their invasion into human pharyngeal epithelial cells. Microb. Pathog. 27:71-80.[CrossRef][Medline]
15
- Kreikemeyer, B., S. Talay, and G. S. Chhatwal. 1995. Characterization of a novel fibronectin-binding surface protein in group A streptococci. Mol. Microbiol. 17:137-145.[Medline]
16
- Lowe, A. M., P. A. Lambert, and A. W. Smith. 1995. Cloning of an Enterococcus faecalis endocarditis antigen: homology with adhesins from some oral streptococci. Infect. Immun. 63:703-706.[Abstract]
17
- Musser, J. M., A. R. Hauser, M. H. Kim, P. M. Schlievert, K. Nelson, and R. K. Selander. 1991. Streptococcus pyogenes causing toxic-shock-like syndrome and other invasive diseases: clonal diversity and pyrogenic exotoxin expression. Proc. Natl. Acad. Sci. USA 88:2668-2672.[Abstract/Free Full Text]
18
- Natanson, S., S. Sela, A. E. Moses, J. M. Musser, M. G. Caparon, and E. Hanski. 1995. Distribution of fibronectin-binding proteins among group A streptococci of different M types. J. Infect. Dis. 171:871-878.[Medline]
19
- Rocha, C. L., and V. A. Fischetti. 1999. Identification and characterization of a novel fibronectin-binding protein on the surface of group A streptococci. Infect. Immun. 67:2720-2728.[Abstract/Free Full Text]
20
- Schneewind, O., P. Model, and V. A. Fischetti. 1992. Sorting of protein A to staphylococcal cell wall. Cell 70:267-281.[CrossRef][Medline]
21
- Sela, S., A. Aviv, A. Tovi, I. Burstein, M. G. Caparon, and E. Hanski. 1993. Protein F: an adhesin of Streptococcus pyogenes binds fibronectin via two distinct domains. Mol. Microbiol. 10:1049-1055.[Medline]
22
- Spellerberg, B., E. Rozdzinski, S. Martin, J. Weber-Heynemann, N. Schnitzler, R. Lütticken, and A. Podbielski. 1999. Lmb, a protein with similarities to LraI adhesin family, mediates attachment of Streptococcus agalactiae to human laminin. Infect. Immun. 67:871-878.[Abstract/Free Full Text]
23
- Stevens, D. L. 1992. Invasive group A streptococcus infections. Clin. Infect. Dis. 14:2-13.[Medline]
24
- Sutcliffe, I., and R. R. B. Russell. 1995. Lipoproteins of gram-positive bacteria. J. Bacteriol. 177:1123-1128.[Free Full Text]
25
- Switalski, L. M., P. Speziale, M. Höök, T. Wadströme, and R. Timpl. 1984. Binding of Streptococcus pyogenes to laminin. J. Biol. Chem. 259:3734-3738.[Abstract/Free Full Text]
26
- Talay, S. R., P. Valentin-Weigand, K. N. Timmis, and G. S. Chhatwal. 1994. Domain structure and conserved epitopes of Sfb protein, the fibronectin-binding adhesin of Streptococcus pyogenes. Mol. Microbiol. 13:531-539.[Medline]
27
- Tao, L., D. J. LeBlanc, and J. Ferretti. 1992. Novel streptococcal-integration shuttle vectors for gene cloning and inactivation. Gene 120:105-110.[CrossRef][Medline]
28
- Terao, Y., S. Kawabata, E. Kunitomo, J. Murakami, I. Nakagawa, and S. Hamada. 2001. Fba, a novel fibronectin-binding protein from Streptococcus pyogenes, promotes bacterial entry into epithelial cells, and the fba gene is positively transcribed under the Mga regulator. Mol. Microbiol. 42:75-86.
29
- von Heijne, G. 1986. A new method for predicting signal sequence cleavage sites. Nucleic Acids Res. 14:4683-4690.[Abstract/Free Full Text]
Infection and Immunity, February 2002, p. 993-997, Vol. 70, No. 2
0019-9567/01/$04.00+0 DOI: 70.2.993-997.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.
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