Fig 4.

Delineation of CagA amino acid sequences involved in SHP-2 interaction. (a) AGS cells were transfected with the indicated CagA expression vectors. WT or mutant CagA proteins then were immunoprecipitated from the cell lysates with anti-HA. The immunoprecipitates (IP) and total cell lysates (TCL) were immunoblotted (IB) with antibodies as described. ABC^Dcc mutant was made from ABCcc by replacing a 5-aa sequence that immediately follows the phosphotyrosine (pY) with an 8-aa sequence from the corresponding region of F32-CagA (see Fig. 3a, black-boxed sequences). A point mutant of ABCcc, ABC^970DFcc, was made by replacing aspartic acid at the position pY + 5 with phenylalanine to mimic the ESS sequence (Fig. 3a arrows). Reciprocally, ABD^961FD was made from ABD by substituting phenylalanine at the position pY + 5 with aspartic acid to mimic WSS. (b) AGS cells used in a then were examined for the induction of the hummingbird phenotype.