09 February 2001
Vol 291, Issue 5506

About The Cover

Cover image expansion

COVER Vesicles that form on the inner surface of cellular membranes capture and internalize extracellular substances for import into eukaryotic cells. This electron micrograph shows these vesicular buds in vitro (bud diameter, ~77 nanometers), coated with the protein clathrin. The adaptor proteins, AP180 and AP2, nucleate the formation of these invaginated buds on lipid monolayers containing phosphatidylinositol-4,5-bisphosphate. This specimen was visualized by rotary platinum shadowing. See page 1051 [Image: M. K. Higgins]