Rabgeranylgeranylotransferaz

Rabgeranylgeranyltransferase, often abbreviated as GGTase, is a crucial enzyme in cellular biology. It belongs to the prenyltransferase family, a group of enzymes responsible for attaching isoprenoid lipid groups to proteins. Specifically, GGTase catalyzes the transfer of a geranylgeranyl moiety, a 20-carbon isoprenoid, from a geranylgeranyl pyrophosphate (GGPP) donor molecule to a target protein.

This process, known as geranylgeranylation, is a type of post-translational modification. It is essential for the proper localization, function, and stability of a wide range of cellular proteins. Many proteins that undergo geranylgeranylation are involved in signaling pathways, membrane trafficking, and cytoskeletal organization. The attached lipid group enhances the protein's hydrophobicity, allowing it to associate with cellular membranes.

GGTase typically recognizes specific C-terminal consensus sequences on its target proteins, such as the CVLS or LCVL motif. Once attached, the geranylgeranyl group can influence protein-protein interactions, membrane binding affinity, and enzymatic activity. Disruptions in GGTase activity or substrate availability can lead to various cellular dysfunctions and are implicated in several diseases. The enzyme plays a vital role in maintaining cellular homeostasis.