All cells rely on special membrane domains to take up nutrients from their environment. Sometimes these domains are commandeered by viral pathogens or malfunction in certain disease states. One of these domains is the clathrin-coated pit, which is specialized to carry macromolecules like LDL into cells. Another is the caveola, which is specialized for delivering small molecules like folate. The Anderson laboratory has made essential contributions to our understanding of how both domains function. The co-discovery of receptor-mediated endocytosis by coated pits, the discovery of an essential role for cholesterol in caveolae structure and function, the identification of the first caveolae marker protein caveolin-1, and the demonstration that caveolae are containers that compartmentalize multiple signaling modules and carry them to different cellular locations, are among the laboratory’s many accomplishments. Today the laboratory is concentrating on four fundamental questions in endocytosis biology. One has to do with the mechanism of caveolae internalization. Three different modes of internalization have been identified, but the structural and regulatory machinery involved in each pathway is not known. We also do not know how receptors cluster in membrane domains, so several projects are aimed towards understand receptor clustering in caveolae and coated pits. Many small molecules and ions are internalized by caveolae, but we are interested in lipids like cholesterol and oleate. We would like to know how lipids are taken up and delivered to adiposomes, the cellular organelle specialized for lipid storage and turnover. Finally, we recently observed that cholesterol has a function outside of membranes in regulating cell signaling. We are working hard to understand the molecular mechanism of cholesterol regulated signal transduction.