Regulator of p53/TP53 stability and function. Inhibits MDM2-mediated degradation of p53/TP53 possibly by cooperating in part with TXNIP. May be involved transcriptional regulation. In vitro has intrinsic transactivation activity enhanced by EP300. May be a transcriptional activator required for the expression of glycolytic genes (By similarity). Involved in regulation of cell cycle progression (PubMed:26711270). Proposed to disrupt Rb-E2F binding leading to transcriptional activation of E2F proteins (PubMed:19640839). The cell cycle -regulating function may depend on its RUVBL1-mediated association with the R2TP complex. May play a role in regulation of pre-mRNA splicing (By similarity). Interacts with TP53, MDM2, TXNIP. Interacts (phosphorylated) with PIH1D1. Interacts with RUVBL1 mediating the PIH1D1-independent association with the R2TP complex. Interacts with RB1, RBL1 and RBL2; ECD competes with E2F1 for binding to hypophospshorylated RB1. Interacts with EP300. Phosphorylated predominantly by CK2 on two serine-containing clusters; involved in cell cycle regulation activity. Embryonic lethal. Belongs to the ECD family.