Figure 1.
Post-translational processing of RAS proteins. Farnesyltransferase (FTase) catalyzes the transfer of a farnesyl group to the terminal cysteine of new synthesized RAS proteins. Next, the three C-terminal amino acids are cleaved by the endopeptidase RAS-converting enzyme 1 (RCE1). Carboxymethylation of of the terminal cysteine residue is accomplished by isoprenylcysteine carboxylmethyltransferase 1 (ICMT1). Finally, palmitoyl transferase (PTase) transfers a palmitoyl group to C-terminal cysteine residues of HRAS, NRAS, and the KRAS-4A isoform.
