The function of ECD (ecdysoneless cell cycle regulator, Ensembl gene identifier ENSG00000122882) is as follows. Regulator of p53/TP53 stability and function. Inhibits MDM2- mediated degradation of p53/TP53 possibly by cooperating in part with TXNIP (PubMed:16849563, PubMed:23880345). 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 (PubMed:19919181, PubMed:9928932). Involved in regulation of cell cycle progression. 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 (PubMed:26711270). May play a role in regulation of pre-mRNA splicing (PubMed:24722212). Participates together with DDX39A in mRNA nuclear export (PubMed:33941617). {ECO:0000269|PubMed:16849563, ECO:0000269|PubMed:19640839, ECO:0000269|PubMed:19919181, ECO:0000269|PubMed:23880345, ECO:0000269|PubMed:26711270, ECO:0000269|PubMed:33941617, ECO:0000305|PubMed:24722212, ECO:0000305|PubMed:9928932}.