and Masanori Hatakeyama Biological activity of the Helicobacter pylori virulence factor CagA is determined by variation in the tyrosine 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

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

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

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

hummingbird phenotype CagA NCTC11637 CagA :Western CagA-specific sequence WSS P SHP-2 P F32 CagA : Ester CagA-specific sequenceESS hummingbird phenotype

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

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

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

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.

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

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

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

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

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

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.

EPIYA→EPIAA

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

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

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

type IV secretion system.