Chemical probes for the rapid detection of fatty-acylated proteins in mammalian cells

The attachment of lipids onto proteins modulates the activity of proteins in many biological settings. The analysis of protein lipidation, however, is challenging due to the relatively few methods for the detection of lipid-modified proteins. Here we describe the synthesis of omega-azido-fatty acids as non-radioactive chemical probes for the rapid visualization of fatty-acylated proteins in mammalian cells. Following metabolic installation of the omega-azido-fatty acids onto target proteins by cellular enzymes, fatty-acylated proteins are selectively biotinylated with a phosphine-biotin reagent via the Staudinger ligation and visualized by streptavidin blotting. Depending on the chain length of the omega-azido-fatty acids, N-myristoylated and S-palmitoylated proteins can be visualized selectively in cell lysates and on specific proteins. These chemical probes provide new tools to analyze fatty acylation of proteins in living cells.