Farnesylation is the process by which a cysteine residue in the C-terminal region of some eukaryotic proteins is posttranslationally modified with an isoprenoid lipid (the 15-carbon farnesyl group) and the exposed carboxyl group is methylated (Fig. 1). The farnesylation and carboxylmethylation increase the affinity of the protein for the membrane and have important functional consequences. The farnesyl group is one of several lipids that act as a membrane anchor for proteins. The role of the farnesyl group and other lipids in membrane anchoring is described in more detail elsewhere [see Prenylation; Membrane Anchors]
Figure 1. Modification of a C-terminal cysteine residue by a farnesyl group.
