@article {Shrivastava109884, author = {Rahul Shrivastava and Xiang{\textquoteright}Er Jiang and Shu-Sin Chng}, title = {Outer membrane lipid homeostasis via retrograde phospholipid transport in Escherichia coli}, elocation-id = {109884}, year = {2017}, doi = {10.1101/109884}, publisher = {Cold Spring Harbor Laboratory}, abstract = {The outer membrane (OM) is essential for viability in Gram-negative bacteria, yet mechanisms to ensure its stability and homeostasis are not understood. The trans-envelope Tol-Pal complex, whose physiological role has remained elusive, is important for OM stability. Here, we establish that the Tol-Pal complex is required for PL transport and OM lipid homeostasis in Escherichia coli. Cells lacking the complex exhibit defects in lipid asymmetry and accumulate excess phospholipids (PLs) in the OM. This imbalance in OM lipids is due to defective retrograde PL transport in the absence of a functional Tol-Pal complex. Thus, cells ensure the assembly of a stable OM by maintaining an excess flux of PLs to the OM only to return the surplus to the inner membrane. Our findings also provide insights into the mechanism by which the Tol-Pal complex may promote OM invagination during cell division.}, URL = {https://www.biorxiv.org/content/early/2017/05/23/109884}, eprint = {https://www.biorxiv.org/content/early/2017/05/23/109884.full.pdf}, journal = {bioRxiv} }