While it is possible to analyze the global lipid composition of a cell, a deeper understanding of what lipids are doing within that cell is more difficult to come by. Though the lipid components may be known, finding their exact position, how dynamically they change location, and how rapidly they are metabolized presents an experimental challenge. The obvious approach would be the addition a fluorescent tag, which would allow for imaging of lipids in cells. Unfortunately, most commonly used fluorescent tags are as large as the lipid itself and are likely to have a strong effect on lipid location and metabolism.

In the July issue of Cold Spring Harbor Protocols, Joachim Goedhart and colleagues present a suite of protocols to get around these problems and allow for live imaging of lipids in cells. Their introduction to the topic explains the approach:

To circumvent this problem, two solutions have been developed–namely, the use of fluorescently labeled proteins that specifically recognize lipids and a chemical method to introduce the fluorescent tag inside the cell.

Protocols are provided for Transfection of Cells with DNA Encoding a Visible Fluorescent Protein-Tagged Lipid-Binding Domain, Labeling Lipids for Imaging in Fixed Cells, and Labeling Lipids for Imaging in Live Cells.