Figure 2.

LapB–FtsH-mediated proteolytic turnover of LpxC is regulated by LapC, and LapB couples the LPS synthesis with its translocation. In this process, LapC acts as an antagonist of LapB, preventing unwanted proteolysis of LpxC. Model of LPS synthesis with LapB acting as a scaffold to assemble LPS and couple the LPS synthesis to its translocation by the Lpt system. MsbA flips LPS after the completion of its assembly on the inner side of IM to the outer leaflet of IM for its delivery to Lpt proteins. Based on interactions of LapB with WaaC and other LPS biosynthetic enzymes, some of them are depicted in this scheme of LPS assembly.