14428–14433 PNAS October 29 , 2002 vol. 99 no. 22 Speaker ：林冠勳 Professor ：吳夙欽 2002/11/05

1. Biological activity of the Helicobacter pylori virulencefactor CagA is determined by variation in thetyrosine phosphorylation sites Hideaki Higashi, Ryouhei Tsutsumi, Akiko Fujita, Shiho Yamazaki†, Masahiro Asaka, Takeshi Azuma†, and Masanori Hatakeyama 14428–14433 PNAS October 29 , 2002 vol. 99 no. 22 Speaker：林冠勳 Professor：吳夙欽 2002/11/05

2. Helicobacter pylori ( H. pylori ) • Gram-negative bacterium • Cause chronic gastritis and gastroduodenal ulcers • Associate with the gastric cancer and MALT lymphoma • Infection half of the world’s population

3. Cytotoxin associated gene A (cagA) • Signal the nucleus to release I L-8 • High immunogenicity • 128 ~ 145 kDa protein • Inject into host cell by type IV secretion system • Tyrosine phosphorylation in host cell

4. Activation is dependent on a membrane-associated host cellular kinase that phosphorylates CagA at multiple sites AGS cell infect (Confocal laser scanning microscopy) CagA SHP-2 actin 10 mm. hummingbird phenotype

5. CagA NCTC11637 CagA :Western CagA-specific sequenceWSS P SHP-2 F32 CagA : Ester CagA-specific sequenceESS P hummingbird phenotype

6. Expression Vector Constructs H.pylori standard strain NCTC11637 C-terminal hemagglutinin (HA) or Flag-epitope-tagged. cagAgene pSP65SRα mammalian expression vector

7. SH2 protein tyrosine phosphatase 2 (SHP-2) • Cytoplasmic tyrosine phosphatase • SH2：src homology 2 domains binding to protein • PTP：protein tyrosine phosphatase catalysis of protein tyrosine dephosphorylation N-SH2 C-SH2

8. SHP-2-Myc SHP-2-SH2∆C-Myc : R138 and H169→ alanine SHP-2-SH2∆N-Myc : Arg-32 (R32) and His-53 (H53) → alanine SHP-2-SH2∆NC-Myc : R138 and H169, Arg-32 (R32) and His-53 (H53) → alanine Human SHP-2 cDNA Myc-epitope pSP65SRα mammalian expression vector

9. CagA and SHP-2 expression vectors Lipofectamine calcium phosphate method Human AGS gastric epithelial cells monkey COS-7 cells 17 h after transfection Hummingbird phenotype lysed in lysis buffer Immunoprecipitation and Immunoblotting.

10. Identification of in Vivo Tyrosine Phosphorylation Sites in the EPIYA Containing Repeat Sequence of CagA The EPIYA motifs present in NCTC11637 CagA X: EPIYA→EPIAA

11. Identification of tyrosine phosphorylation sites of CagA and their roles in SHP-2 binding and morphological transformation immunoprecipitates (IP) total cell lysates (TCL)

12. Correlation Among Number of Tyrosine Phosphorylation Sites, SHP-2-Binding Activity, and Hummingbird Phenotype Induction of CagA.

13. AGS cells were transiently transfected with an expression vector for WT or EPIYA mutant of CagA. Cells showing the hummingbird phenotype were counted.

14. Involvement of the SH2 Domains of SHP-2 in CagA Binding

15. COS-7 cells were cotransfected with expression vectors for HA-tagged CagA and Flag-taggedCagA. Cell lysates were subjected to immunoprecipitation (IP) with anti-Flag. Immunoprecipitates and total cell lysates (TCL) were immunoblotted (IB) with the indicated antibodies A model of CagA–SHP-2 interaction.

16. EPIYA→EPIAA

17. The relative amounts of tyrosine phosphorylated CagA(black bars) CagA-bound SHP-2 (white bars) were calculated with the values for WT 11637-CagA

18. Delineation of Amino Acid Residues That Determine SHP-2-Binding Affinity Among Distinctly Structured CagA Proteins ABCcc : ABCDcc : ABC970DFcc : ABD961FD :

19. AGS cells used in a then were examined for the induction of the hummingbird phenotype.

20. type IV secretion system.