RB1 and neoplasm: In addition to binding Daxx, independent work showed that pp71 also bound to other cellular transcriptional repressors, namely the Rb family of tumor suppressors, Rb, p107, and p130, and induced their proteasome-dependent, ubiquitin-independent degradation (Kalejta and Shenk, 2003a,b; Kalejta et al., 2003).