Lipid raft microdomains offer a means to enhance the local concentration of membrane components as well as serve as a platform for raft associated endocytosis. Driven by membrane dynamics, raft associated endocytosis leads to the membrane tubule formation and the creation of vesicles to transport material across the membrane. Although it is hypothesized that both receptor clustering and the presence of cholesterol are required, a mechanistic explanation for this phenomenon remains unclear. We propose to use NR to investigate this mechanism by studying the influence of cholera toxin binding to GM1 on the selective recruitment of cholesterol. Two experimental approaches will be implemented: measuring relative concentration of cholesterol in membrane leaflets and investigating the kinetics of cholesterol recruitment from a lipid rich reservoir in the opposing leaflet.