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).