PROSITE documentation PDOC00266

Prenyl group binding site (CAAX box)

A number of eukaryotic proteins are post-translationally modified by the attachment of either a farnesyl or a geranyl-geranyl group to a cysteine residue [1,2,3,4]. The modification occurs on cysteine residues that are three residues away from the C-terminal extremity; the two residues that separate this cysteine from the C-terminal residue are generally aliphatic. This Cys-Ali-Ali-X pattern is generally known as the CAAX box. Proteins known or strongly presumed to be the target of this modification are listed below.

• Ras proteins, and ras-like proteins such as Rho, Rab, Rac, Ral, and Rap.
• Nuclear lamins A and B.
• Some G protein α subunits.
• G protein γ subunits (see <PDOC01002>).
• 2',3'-cyclic nucleotide 3'-phosphodiesterase (EC 3.1.4.37).
• Rhodopsin-sensitive cGMP 3',5'-cyclic nucleotide phosphodiesterase α and β chains (EC 3.1.4.17).
• Rhodopsin kinase (EC 2.7.11.14).
• Some dnaJ-like proteins (such as yeast MAS5/YDJ1).
• A number of fungal mating factors (such as M-factor or rhodotorucine A).