Title: Streptococcus pneumonia surface protein SpsA CbpA binds human pIgR via domains 3 and 4
1Streptococcus pneumonia surface protein SpsA
(CbpA) binds human pIgR via domains 3 and 4
- Finn-Eirik Johansen, Ranveig Braathen, Christine
Elm and Sven Hammerschmidt - Section for secretory immunity and B cells,
Laboratory for Immunohistochemistry and
Immunopathology, Rikshospitalet University
Hospital - Research Center for Infectious Diseases,
University Würzburg, Würzburg, Germany
2Streptococcus pneumoniae
- Causes relatively harmless infections like otitis
media and sinusitis as well as life-threatening
disease such as pneumonia, septicemia and
meningitis. - Invades host via nasopharyngeal epithelium.
- A surface-displayed virulence factor, SpsA, binds
specifically to SC/pIgR (Hammerschmidt 97, Mol.
Micorobiol.). - Invation of nasopharyngeal epithlial cells
depends on CbpA/SpsA binding to pIgR (Zhang 2000
Cell). - CbpA/SpsA interaction with SC/pIgR is specific
for human SC (Hammerschmidt 2000 Mol.
Microbiol.).
3Lumen
Secretory epithelium
As previous
Lamina propria
IgAJ
IgAJ
Plasma cell
4Binding and internalization of SpsA-coated beads
to pIgR-expressing epithelial cells
5Binding of human, mouse and chimeric SC to SpsA
fragments (SH2 or SH3) and dIgA
dIgA
SH2
SH3
H
H1
H2
H3
H4
H5
M
M1
M2
M3
M4
M5
0
1
2
0.5
1.0
1.5
OD405
OD405
6Human SC domains D3 and D4 are necessary and
sufficient for SpsA binding when grafted onto
mouse SC
H
M
Hd3
Hd4
Hd3d4
Md3
Md4
0
0,5
1
1,5
2
2,5
OD405
7Alignment of human and mouse D3 and D4
Domain 3
220 human LKPEPELVYEDLRGSVTFHCALGPEVANVAKF
LCRQSSGENCDVVVNTLGKRAPAFEG mouse
-a-----l-k---s----e-d--r----e--y---mnk.-t---ii----
--d-d---
334 human
RILLNPQDKDGSFSVVITGLRKEDAGRYLCGAHSDGQLQEGSPIQAWQLF
VNEESTI mouse ---it-k-dn-r---l----------h-q-----s
-lp---w---t----------- 335 human
PRSPTVVKGVAGSSVAVLCPYNRKESKSIKYWCLWEGAQNGRCPLLVDSE
GWVKAQY mouse -nrrs-----t-g---ia----p---s-l----r-
--dg--h--v--gtqaq-qee-
445 human
EGRLSLLEEPGNGTFTVILNQLTSRDAGFYWCLTNGDTLWRTTVEIKIIE
G..EPN mouse ----a-fdq-----y--------te-----------
-sr----i-lqva-atr---
Domain 4
8Analysis of SpsA binding of mutants in D3 of
human SC
9Alignment of human and mouse D3 and D4
Domain 3
Domain 4
10Analysis of SpsA binding of mutants in D3 of
human SC
11Analysis of SpsA binding of mutants in D3 of
human SC
H
282-285A
N282A
Q284A
D285A
0
0,5
1
1,5
2
2,5
OD405
12Alignment of human and mouse D3 and D4
Domain 3
220 human LKPEPELVYEDLRGSVTFHCALGPEVANVAKF
LCRQSSGENCDVVVNTLGKRAPAFEG mouse
-a-----l-k---s----e-d--r----e--y---mnk.-t---ii----
--d-d---
334 human
RILLNPQDKDGSFSVVITGLRKEDAGRYLCGAHSDGQLQEGSPIQAWQLF
VNEESTI mouse ---it-k-dn-r---l----------h-q-----s
-lp---w---t----------- 335 human
PRSPTVVKGVAGSSVAVLCPYNRKESKSIKYWCLWEGAQNGRCPLLVDSE
GWVKAQY mouse -nrrs-----t-g---ia----p---s-l----r-
--dg--h--v--gtqaq-qee-
445 human
EGRLSLLEEPGNGTFTVILNQLTSRDAGFYWCLTNGDTLWRTTVEIKIIE
G..EPN mouse ----a-fdq-----y--------te-----------
-sr----i-lqva-atr---
282-285
Domain 4
13Analysis of SpsA binding of mutants in D4 of
human SC
H
336-339A
347-351A
382-386A
387-390A
0
0,5
1
1,5
2
OD405
14Analysis of SpsA binding of mutants in D4 of
human SC
15Alignment of human and mouse D3 and D4
Domain 3
220 human LKPEPELVYEDLRGSVTFHCALGPEVANVAKF
LCRQSSGENCDVVVNTLGKRAPAFEG mouse
-a-----l-k---s----e-d--r----e--y---mnk.-t---ii----
--d-d---
334 human
RILLNPQDKDGSFSVVITGLRKEDAGRYLCGAHSDGQLQEGSPIQAWQLF
VNEESTI mouse ---it-k-dn-r---l----------h-q-----s
-lp---w---t----------- 335 human
PRSPTVVKGVAGSSVAVLCPYNRKESKSIKYWCLWEGAQNGRCPLLVDSE
GWVKAQY mouse -nrrs-----t-g---ia----p---s-l----r-
--dg--h--v--gtqaq-qee-
445 human
EGRLSLLEEPGNGTFTVILNQLTSRDAGFYWCLTNGDTLWRTTVEIKIIE
G..EPN mouse ----a-fdq-----y--------te-----------
-sr----i-lqva-atr---
N282
Domain 4
W386
16Conclusions
- SpsA interacts with D3 and D4 in human pIgR/SC.
- Amino acid N282 in D3 is essential for SpsA
interaction. - Amino acid W386 in D4 is necessary for SpsA
interaction. - This interaction is important in Streptococcus
pneumoniae pathogenesis.