Proteolytically removes the C-terminal three residues of farnesylated and geranylated proteins. Seems to be able to process K-Ras, N-Ras, H-Ras, RAP1B and G-gamma-1 (PubMed:10085068). Deubiquitination by USP17L2/USP17 negatively regulates the proteolytic activity toward Ras GTPases. Ubiquitous. Ubiquitinated. Undergoes 'Lys-48'- and 'Lys-63'-linked ubiquitination. 'Lys-48' ubiquitination induces its degradation. Deubiquitinated by USP17L2/USP17 that cleaves 'Lys-63'-linked ubiquitin chains. Belongs to the peptidase U48 family.