The plasma membrane of the mammalian cell is organized into domains that have different protein and lipid compositions. The ability to image protein components of interest in cell membranes with high spatial resolution and selectivity has revealed that the functions of some membrane proteins are correlated with their distribution within the membrane.  Cholesterol, sphingolipids, and other lipid species are also expected to have non-random distributions within cellular membranes that are required for membrane function.  Here we probe this expectation by using a high-resolution secondary ion mass spectrometry (SIMS) approach to image isotope-labeled lipids and proteins of interest in mammalian cell membranes with ≤100-nm-lateral resolution. Our SIMS imaging revealed that sphingolipids are located within micrometer-scale plasma membrane domains, but cholesterol is evenly distributed on the cell surface. By imaging isotope-labeled cholesterol and sphingolipids in parallel with immunolabeled membrane proteins, we have tested the hypothesis that the influenza virus envelope protein, hemagglutinin, clusters within cholesterol- and sphingolipid-enriched plasma membrane domains. We have also used this approach to directly test the hypothesis that the influenza virus assembles and buds at regions of the plasma membrane that are enriched with cholesterol and sphingolipids.  <br/>

Interrogating cell membrane organization with secondary ion mass spectrometry

2019 Spring National Meeting

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