Close Encounters of the Oily Kind: Regulation of Transporters by Lipids

Lipid moieties found within high-resolution structures of integral membrane proteins. A) A high-affinity aspartate transporter (GltTph) from Pyrococcus hirokoshii resolved at 3.2Å. Surface representation of a single GltTph monomer, colored by atom type, with the interacting palmitate molecule colored green. At right, the hydrophobic residues that are positioned to interact with the lipid molecule are shown. B) Membrane topology of the human β2-adrenergic receptor based on the crystal structure resolved at 2.4 Å. Intriguingly, association of the two receptor molecules (blue) appears to be mediated by cholesterol (orange). [Adapted from (34, 64).]