Investigating the Mechanisms of Non-Random Sphingolipid Organization in the Plasma Membranes of Fibroblast Cells

Abstract

Sphingolipids and their metabolites are not only structural components in the plasma membrane, but also bioactive signaling molecules that modulate fundamental cellular functions. Though segregation of the sphingolipids into distinct membrane domains is likely essential for cellular function, the sphingolipid distribution within the plasma membrane and the mechanisms that regulate it are not well understood. To address this issue, we have combined metabolic stable isotope incorporation and high-resolution secondary ion mass spectrometry (SIMS) to image the distributions of stable isotope-labeled sphingolipids in the plasma membrane with ∼90 nm lateral resolution. We have previously used this approach to show that sphingolipids are enriched within distinct domains in the plasma membranes of fibroblast cells. We have also used this approach to investigate the dependency of the sphingolipid domains on cholesterol-sphingolipid interactions, and the cytoskeleton and its associated membrane proteins. This talk will focus on our recent work in which we have assessed whether the sphingolipid domains are co-localized with influenza hemagglutinin within the plasma membrane.