RT Journal Article
SR Electronic
T1 Outer membrane lipid homeostasis via retrograde phospholipid transport in <em>Escherichia coli</em>
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 109884
DO 10.1101/109884
A1 Rahul Shrivastava
A1 Xiang’Er Jiang
A1 Shu-Sin Chng
YR 2017
UL http://biorxiv.org/content/early/2017/05/23/109884.abstract
AB 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.