The endosomal sorting complex required for transport (ESCRT) complexes sort ubiquitinated membrane proteins into multivesicular bodies, which is a key step in the lysosomal degradation pathway. Shields et al. (Shields, S.B., A.J. Oestreich, S. Winistorfer, D. Nguyen, J.A. Payne, D.J. Katzmann, and R. Piper. 2009. J. Cell Biol. 185:213-224) identify a new ubiquitin-binding site in ESCRT-I and pr...