The E1 and E2 are common enzymes, while E3 ubiquitin ligases are highly substrate specific.27 To delineate the E3 ligase responsible for Survivin degradation controlled by AURKA in gastric cancer cells, we performed mass spectrometry analysis of Survivin immunoprecipitates after treatment with MG132 (data not shown) and identified a number of putative Survivin-interacting E3 ubiquitin ligases. Here, BIRC5 is linked to gastric cancer.