The function of TOPORS (TOP1 binding arginine/serine rich protein, E3 ubiquitin ligase, ENSG00000197579) is as follows. Functions as an E3 ubiquitin-protein ligase and as an E3 SUMO1-protein ligase. Probable tumor suppressor involved in cell growth, cell proliferation and apoptosis that regulates p53/TP53 stability through ubiquitin-dependent degradation. May regulate chromatin modification through sumoylation of several chromatin modification-associated proteins. May be involved in DNA damage-induced cell death through IKBKE sumoylation. {ECO:0000269|PubMed:15247280, ECO:0000269|PubMed:15735665, ECO:0000269|PubMed:16122737, ECO:0000269|PubMed:17803295, ECO:0000269|PubMed:18077445, ECO:0000269|PubMed:19473992, ECO:0000269|PubMed:20188669}.