Geranylgeranylation

Geranylgeranylation is a post-transcriptional modification of proteins that involves the attachment of the isoprene geranylgeranyl diphosphate to the C-terminus at the cysteine residue. It is an intermediate step of the cholesterol biosynthesis pathway, which is used to modify the Rho GTPase family of signaling molecules.

An example of this can be seen in the lipid anchoring of the gamma subunit of heterotrimeric G proteins