Non-lamellar-phase-promoting co-lipids enhance segregation of palmitoyl ceramide in fluid bilayers (Biophysical Journal)

Ceramide is an important intermediate in sphingolipid homeostasis. We examined how co-lipids, with negative intrinsic curvature and which may induce curvature stress in the bilayers, affected the segregation of palmitoyl ceramide (PCer). Such co-lipids include 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE), 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), and tetra-linoleoyl cardiolipin (CL). In 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) bilayers, PCer formed ordered, gel-like domains at concentrations above 10 mol% at 23o C, as evidenced by the change in the average lifetime of the trans-parinaric acid emission.