Lipid-modified proteins are involved in important biological events, such as signal transduction, organisation of the cytoskeleton and vesicular transport. Post-translational S-palmitoylation for example directs the trafficking and membrane localization of hundreds of cellular proteins, often involving a coordinated palmitoylation cycle that requires both protein acyl transferases (PATs) and acyl protein thioesterases (APTs; EC 3.1.2.22). APT1 (a.k.a. LYPLA1) was the first characterized cytosolic protein depalmitoylase, yet initially annotated as a lysophospholipase[1]. Since It was shown that peptides that resemble the dual lipidation motifs of Ras or G-protein α subunits are efficiently palmitoylated and localized at the plasma membrane, the APT1 enzyme is of interest for its role in Ras signaling related oncology research, among other fields of interest[2].