Lipid Organization of the Plasma Membrane

The detailed organization of cellular
membranes remains rather
elusive. Based on large-scale molecular dynamics simulations, we provide
a high-resolution view of the lipid organization of a plasma membrane
at an unprecedented level of complexity. Our plasma membrane model
consists of 63 different lipid species, combining 14 types of headgroups
and 11 types of tails asymmetrically distributed across the two leaflets,
closely mimicking an idealized mammalian plasma membrane. We observe
an enrichment of cholesterol in the outer leaflet and a general non-ideal
lateral mixing of the different lipid species. Transient domains with
liquid-ordered character form and disappear on the microsecond time
scale. These domains are coupled across the two membrane leaflets.
In the outer leaflet, distinct nanodomains consisting of gangliosides
are observed. Phosphoinositides show preferential clustering in the
inner leaflet. Our data provide a key view on the lateral organization
of lipids in one of life’s fundamental structures, the cell
membrane.