Lipid rafts: signaling and sorting platforms of cells and their roles in cancer

Lipid rafts are defined as microdomains within the lipid bilayer of cellular membranes that assemble subsets of transmembrane or glycosylphosphatidylinisotol-anchored proteins and lipids (cholesterol and sphingolipids) and experimentally resist extraction in cold detergent (detergent-resistant membrane). These highly dynamic raft domains are essential in signaling processes and also form sorting platforms for targeted protein traffic. Lipid rafts are involved in protein endocytosis that occurs via caveolae or flotillin-dependent pathways. Non-constitutive protein components of rafts fluctuate dramatically in cancer with impacts on cell proliferation, signaling, protein trafficking, adhesion and apoptosis. This article focuses on the identification of candidate cancer-associated biomarkers in carcinoma cells using state-of-the-art proteomics.