An shRNA screen to search for the mediators of pancreatic cancer metastasis identified palmitoyl transferase ZDHHC20 as a protein that mediates this process by promoting the outgrowth of metastatic cells in vivo. We sought to identify the substrates of ZDHHC20 by using an engineered mutant of ZDHHC20 with a Y181G substitution, which can selectively accommodate a synthetic lipid probe and transfer it to a protein substrate.