9.B.27.2.2
The YqjA protein is 60% identical to YghB, and these two act synergistically to maintain a normal pmf (Kumar and Doerrler 2015). Perhaps secondarily, when both YghB and YqjA are mutated, the cells exhibit a cell division defect (Thompkins et al., 2008). It has been proposed that YqjA possesses proton-dependent transport activity that is stimulated by osmolarity and that it plays a significant role in the survival of E. coli at alkaline pH, perhaps as an osmosensory cation-dependent proton transporter (a cation:proton antiporter?) (Kumar and Doerrler 2015).