Push–Pull Mechanism for Lipid Raft Formation

Abstract

A quantitative assessment has been made of the interaction between exchangeable mimics of 1-palmitoyl-2-oleoyl-<i>sn</i>-glycero-3-phosphocholine (POPC) and cholesterol in the liquid-ordered (<i>l</i>₀) and the liquid-disordered (<i>l</i>_d) states using the nearest-neighbor recognition (NNR) method. This assessment has established that these lipids mix ideally in the <i>l</i>₀ phase (i.e., they show no net attraction or repulsion toward each other) but exhibit repulsive interactions in the <i>l</i>_d phase. The implications of these findings for the interactions between unsaturated phospholipids and cholesterol in eukaryotic cell membranes are briefly discussed