Cooperative Regulation of Membrane Domain Registration by Lipid Headgroup Size and Cholesterol Dynamics

Lipid domains in cellular membranes can adopt either registered or anti-registered configurations between the two leaflets, playing crucial roles in numerous cellular processes. However, the microscopic mechanisms governing domain registration and anti-registration remain incompletely understood due to the complexity of interleaflet interactions. In this work, we investigate the effects of lipid headgroup size and cholesterol concentration on domain registration using coarse-grained molecular dynamics simulations. Through a free energy perturbation (FEP)-like method, we systematically demonstrate that headgroup size and cholesterol concentration cooperatively regulate domain registration by modulating the membrane curvature and line tension at domain boundaries. Furthermore, cholesterol flip-flop strengthens interleaflet coupling, thereby facilitating domain registration. This work quantitatively reveals how lipid geometric properties and cholesterol concentration and translocation jointly regulate interleaflet coupling, offering novel insights into the molecular mechanisms underlying membrane domain organization. TOC Graphic O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=114 SRC="FIGDIR/small/699701v1_ufig1.gif" ALT="Figure 1"> View larger version (43K): org.highwire.dtl.DTLVardef@ef52b7org.highwire.dtl.DTLVardef@1fa026org.highwire.dtl.DTLVardef@4b2d36org.highwire.dtl.DTLVardef@185659d_HPS_FORMAT_FIGEXP M_FIG C_FIG