geranylgeranylylation

Geranylgeranylylation is a type of protein prenylation, a post-translational modification where isoprenoid lipids are attached to proteins. Specifically, geranylgeranylylation involves the addition of a geranylgeranyl group, a 20-carbon isoprenoid, to a target protein. This process is catalyzed by enzymes called geranylgeranyltransferases.

The geranylgeranyl group is typically attached to cysteine residues at the C-terminus of proteins. This modification often occurs at a specific motif within the protein sequence, known as the CaaX box or prenylation motif. The geranylgeranyl moiety is a hydrophobic lipid, and its attachment to the protein serves to anchor it to cellular membranes. This membrane localization is crucial for many proteins, influencing their function, stability, and interaction with other cellular components.

Geranylgeranylylation plays a significant role in various cellular processes, including signal transduction, protein trafficking, and cell growth. Proteins that undergo geranylgeranylylation are involved in diverse pathways, such as the Ras signaling pathway and the regulation of small GTPases. Dysregulation of geranylgeranylylation has been implicated in several diseases, including cancer and neurological disorders, making it a target for therapeutic intervention. The specific enzymes responsible for catalyzing geranylgeranylylation, such as Rab geranylgeranyltransferase, are essential for the proper functioning of these downstream proteins.