Shrinking patches and slippery rafts: Scales of domains in the plasma membrane

Many types of experiment show that the plasma membranes of cells are patchy and locally differentiated into domains. Some of these domains seem to arise through the confinement of diffusible membrane proteins. Others might arise through lipid-lipid interactions. Both types of domain are transient on a biological timescale but both could create local conditions that enhance molecular interactions, such as those that occur in receptor-mediated signaling.