Imaging the lipidome: omega-alkynyl fatty acids for detection and cellular visualization of lipid-modified proteins.

Fatty acylation or lipid modification of proteins controls their cellular activation and diverse roles in physiology. It mediates protein-protein and protein-membrane interactions and plays an important role in regulating cellular signaling pathways. Currently, there is need for visualizing lipid modifications of proteins in cells. Herein we report novel chemical probes based on omega-alkynyl fatty acids for biochemical detection and cellular imaging of lipid-modified proteins. Our study shows that omega-alkynyl fatty acids of varying chain length are metabolically incorporated onto cellular proteins. Using fluorescence imaging, we describe the subcellular distribution of lipid-modified proteins across a panel of different mammalian cell lines and during cell division. Our results demonstrate that this methodology is a useful diagnostic tool for analyzing the lipid content of cellular proteins and for studying the dynamic behavior of lipid-modified proteins in various disease or physiological states.