Figure 1.

Protein Farnesylation, Proteolysis, Methylation, Demethylation, Degradation, and Recycling of the Farnesyl Group.

The transfer of a farnesyl group from farnesyl diphosphate to a CaaX protein is followed by postisoprenylation processing (proteolysis and reversible methylation). Degradation of the farnesylated protein generates FC, which is oxidized by FC lyase to farnesal. Farnesal is then reduced to farnesol, which is phosphorylated to farnesyl diphosphate to complete the cycle. Gene names are indicated in italics. CDP, cytidine diphosphate; CTD, cytidine triphosphate; CHO, aldehyde; OPP, diphosphate; SAH, S-adenosyl-l-homocysteine; SAM, S-adenosyl-l-methionine.