This family consists of several bacterial phage shock protein B (PspB) sequences. The phage shock protein (psp) operon is induced in response to heat, ethanol, osmotic shock and infection by filamentous bacteriophages [1]. Expression of the operon requires the alternative sigma factor sigma54 and the transcriptional activator PspF. In addition, PspA plays a negative regulatory role, and the integral-membrane proteins PspB and PspC play a positive one [2].

1: Characterization and sequence of the Escherichia coli stress-induced psp operon. Brissette JL, Weiner L, Ripmaster TL, Model P; J Mol Biol 1991;220:35-48. PMID:1712397

2: Interactions between phage-shock proteins in Escherichia coli. Adams H, Teertstra W, Demmers J, Boesten R, Tommassen J; J Bacteriol 2003;185:1174-1180. PMID:12562786