The CpxA/R two-component signal transduction system of Escherichia col
i can combat a variety of extracytoplasmic protein-mediated toxicities
, The Cpx system performs this function, in part, by increasing the sy
nthesis of the periplasmic protease, DegP, However, other factors are
also employed by the Cpx system for this stress-combative function, In
an effort to identify these remaining factors, we screened a collecti
on of random lacZ operon fusions for those fusions whose transcription
is regulated by CpxA/R, Through this approach, we have identified a n
ew locus, cpxP, whose transcription is stimulated by activation of the
Cpx pathway, cpxP specifies a periplasmic protein that can combat the
lethal phenotype associated with the synthesis of a toxic envelope pr
otein, In addition, we show that cpxP transcription is strongly induce
d by alkaline pH in a CpxA-dependent manner and that cpxP and cpx muta
nt strains display hypersensitivity to growth in alkaline conditions.