Lipid scrambling: New players, new questions, new opportunities

Nearly a quarter of the proteins encoded in most organisms are transmembrane proteins. Contrary to textbook description, many feature a hydrophilic groove which is laterally exposed to the hydrophobic region of the lipid membrane. This cavity is stabilized by neighboring lipid headgroups that sink deep into the membrane and consequently move bidirectionally from one leaflet to the other, in a process nicknamed lipid 'scrambling.' These proteins, called scramblases, have been reported to serve in