The endocytic pathway: A mosaic of domains

Organelles in the endocytic pathway are composed of a mosaic of structural and functional regions. These regions consist, at least in part, of special ized protein-lipid domains within the plane of the membrane, or of protein complexes associated with specific membrane lipids. Whereas some of these m olecular assemblies can be found in more than one compartment, a given comb ination seems to be unique to each compartment, indicating that membrane or ganization might be modular.