Multivesicular bodies (MVBs) deliver cargo destined for degradation to the vacuole or lysosome. The ESCRT (endosomal sorting complex required for transport) pathway is a key mediator of MVB biogenesis, but it also plays critical roles in retroviral budding and cytokinetic abscission. Despite these diverse roles, the ESCRT pathway can be simply seen as a cargo-recognition and membrane-sculpting machine viewable from three distinct perspectives: (1) the ESCRT proteins themselves, (2) the cargo they sort, and (3) the membrane they deform. Here, we review ESCRT function from these perspectives and discuss how ESCRTs may drive vesicle budding.
