Hug and hold tight: Dimerization controls the turnover of the ubiquitin-conjugating enzyme UBE2S.

Precise control of the activity and abundance of ubiquitin-conjugating enzymes (E2s) ensures fidelity in ubiquitin chain synthesis. In this issue of Science Signaling, Liess et al. demonstrate that the human anaphase-promoting complex (APC/C)-associated E2 UBE2S adopts an autoinhibited dimeric state that increases the half-life of UBE2S by preventing its autoubiquitination-driven turnover.