FIG. 1.

PapG expression induces Cpx in a manner that is dependent on the periplasmic domain of CpxA but does not require NlpE. β-Galactosidase activities were determined for PAD501 (lanes 1 and 2), PAD 486 (lanes 3 and 4), and PAD 504 (lanes 5 and 6). pHJ8 is an IPTG-inducible PapG overexpression plasmid (20). zii::Tn10 is commonly used to move Cpx alleles and has no effect on Cpx-mediated signal transduction (31). The cpxA24 strain is signal blind to PapG expression (compare lanes 5 and 6 to lanes 1 and 2). The nlpE null strain is induced to wild-type (WT) levels upon PapG expression (compare lanes 1 and 2 to lanes 3 and 4). All strains were grown and induced as described in Materials and Methods.