Abstract

Endosomes, which comprise a diverse population of membrane vesicles and tubules, sort proteins and lipids to various cellular destinations. The organization and functions of these pleiomorphic cellular organelles have been extensively studied. Matsuo et al.1 now provide new exciting evidence on the role of lysobiphosphatidic acid (LBPA), a resident phospholipid of internal vesicles of the late endosome, in the control of membrane invagination and endosome biogenesis. In vivo, LBPA functions are controlled by the adaptor protein Alix and depend on pH gradients along the endosomal compartments. BioEssays 26:604–607, 2004. © 2004 Wiley Periodicals, Inc.