Membrane domains form when specific protein-protein, protein-lipid, and lipid-lipid interactions create distinct areas within the membrane. Some membrane proteins interact to form large protein complexes in the membrane that inhibit their lateral movement. Membrane domains can also form when proteins are tethered to the cytoskeleton or restricted to a specific membrane compartment due to cytoskeletal fences. Proteins and specific lipids can interact preferentially and organize into small domains. Less soluble phospholipids, sphingolipids, and sterols in the membrane can aggregate to form membrane domains of various sizes. Some proteins have high affinities to specific lipids creating larger lipid-induced domains. These domains concentrate proteins and enable the formation of functional protein complexes.