Peering Deeper Into The Prenylome

An international research team has set out to develop new tools for analyzing the so-called prenylome, a set of natural proteins modified by lipid (prenyl) chains that are involved in a host of mammalian cell processes (Nat. Chem. Biol., DOI: 10.1038/nchembio.149). Bioinformatics studies predict that 2% of human proteins are prenylated by farnesyl or geranylgeranyl groups, according to Kirill Alexandrov of the Institute for Molecular Bioscience, in Brisbane, Australia, and coworkers. Yet the actual number of proteins modified in this way is unknown, they note, even though molecules that inhibit the synthesis of prenylation substrates form the basis of the billion-dollar statin drug market. To better elucidate the scope of prenylation, the team developed a functionalized prenylated compound called BGPP—biotin-geranylpyrophosphate—and reengineered the three known human prenyltransferase enzymes so that they faithfully attach BGPP to cellular substrates. Using this strategy with mass spectrometry detection, the researchers were able to measure femtomole quantities of prenylated proteins and analyze the in vivo effects of prenylation inhibitors. The approach should help unravel the molecular mechanisms behind statins and potentially lead to new drug targets, they say.