A lipid cue drives the subcellular localization of a self-inserting bacterial transmembrane protein
TL;DR
It is demonstrated that the Bacillus subtilis protein ShfA localizes to the forespore by using an intramembrane lipid-binding domain to directly recognize undecaprenyl phosphate, a universal lipid carrier essential for cell wall synthesis.
Abstract
Significance Cues driving the subcellular localization of integral membrane proteins in bacteria are often poorly understood. Using bacterial sporulation as a model for complex membrane reorganization, we demonstrate that the Bacillus subtilis protein ShfA localizes to the forespore by using an intramembrane lipid-binding domain to directly recognize undecaprenyl phosphate, a universal lipid carrier essential for cell wall synthesis. This “targeted insertion” mechanism allows ShfA to bypass the traditional model of membrane insertion followed by lateral diffusion, thereby enabling the protein to spontaneously localize to sites of active peptidoglycan synthesis. Our findings highlight the critical role of lipid–protein interactions in defining different subcellular membrane patches.