A previous study has shown that YopB of Yersinia spp, is essential for tran
slocation of Yop effectors across the eucaryotic plasma membrane (M.-P. Sor
y and G, R. Cornelis, Mol. Microbiol. 14:583-594, 1994). Hows, er, this rol
e was recently challenged (V. T. Lee and O. Schneewind, Mol. Microbiol. 31:
1619-1629, 1999), Using protease protection and digitonin extraction, me re
confirm that YopB of Yersinia enterocolitica is essential for the transloca
tion of YopE into HeLA cell monolayers.