RT Journal Article
SR Electronic
T1 Bacterial outer membrane homeostasis via retrograde phospholipid transport
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 109884
DO 10.1101/109884
A1 Rahul Shrivastava
A1 Shu-Sin Chng
YR 2017
UL http://biorxiv.org/content/early/2017/02/20/109884.abstract
AB The outer membrane (OM) is essential for viability in Gram-negative bacteria, yet mechanisms to ensure its stability and homeostasis are not known. The trans-envelope Tol-Pal complex, whose physiological role has remained elusive, is important for OM stability, and coordinated OM invagination during cell division. Here, we establish the function of the Tol-Pal complex in 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 via transport mediated by the Tol-Pal complex. Our findings also provide insights into the mechanism by which the Tol-Pal complex promotes OM invagination during division.