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9.B.4 The Universal Stress Protein-B (UspB) Family

The UspB family consists of a group of closely related proteins from enteric bacteria of about 110-150 aas and with 2 TMSs. They are expressed in stationary phase under sigma factor, σScontrol. UspB of E. coli is required for stationary phase resistance to ethanol and many mutagens (Farewell et al., 1998; Prytz et al., 2003). There seem to be no homologues of UspB outside of the enterics (Diez et al., 2002). Nothing except topology suggests a function in transport. In fact, this protein has been shown to facilitate RuvC resolvase function during DNA repair and is therefore is  not likely to be a transporter (Persson et al. 2010).

References associated with 9.B.4 family:

Diez, A.A., A. Tunlid, and T. Nystrom. (2002). The Escherichia coli ftsK1 mutation attenuates the induction of σS-dependent genes upon transition to stationary phase. FEMS Microbiol. Lett. 206: 19-23. 11786251
Farewell, A., K. Kvint, and T. Nystrom. (1998). uspB, a new σS-regulated gene in Escherichia coli which is required for stationary-phase resistance to ethanol. J. Bacteriol. 180: 6140-6147. 9829921
Persson, O., T. Nyström, and A. Farewell. (2010). UspB, a member of the sigma-S regulon, facilitates RuvC resolvase function. DNA Repair (Amst) 9: 1162-1169. 20817623
Prytz, I., A.M. Sanden, T. Nystrom, A. Farewell, A. Wahlstrom, C. Forberg, Z. Pragai, M. Barer, C. Harwood, and G. Larsson. (2003). Fed-batch production of recombinant β-galactosidase using the universal stress promoters uspA and uspB in high cell density cultivations. Biotechnol. Bioeng. 83: 595-603. 12827701