Fig. 3. Schematic diagram of the interaction of rhodopsin with the disc membrane. The C terminus (-COOH) is on the cytoplasmic side of the disc and contains the three serines (serines 334, 338, and 343) that are phosphorylated upon activation of rhodopsin by a photon. The N terminus is in the intradiscal space and contains two asparagines (Asn) that are glycosylated. Also shown is the interaction of the two palmitoyl moieties attached to cysteines 322 and 323 with the plasma membrane (yellow solid box). Open boxes represent the hydrophobic domains of rhodopsin that are imbedded in the membrane.