FIG. 1.

Secretion and translocation of translocator N-terminal sequences fused to TEM. (A) Analysis of whole-cell lysates reveals comparable expression levels of the TEM fusions in the different EPEC E2348/69 (E69) strains. (B) Secretion profiling reveal that 20EspA, 20EspB, and 20EspD, but not 20R, can mediate TEM secretion from wild-type EPEC, which was enhanced when the fusions were expressed in the sepD and sepL mutants. 20EspF was included as a positive control. Neither protein was secreted from the escN mutant. Molecular mass markers (in kilodaltons) are indicated to the left. (C) 20EspA, 20EspB, and 20EspD, but not 20R, mediate TEM protein translocation from wild-type EPEC. 20EspF was included as a positive control. The data presented are averages of triplicate values obtained from two independent experiments. The statistical significance (*) of the difference between E69 and E69ΔescN expressing the indicated TEM fusion (horizontal lines) was determined by Student's t test.