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.
Expressed at highest levels in testis and at lower levels in adrenal gland, bone marrow, brain, colon, heart, kidney, liver, muscle, ovary, pancreas, placenta, prostate, skeletal muscle, skin, small intestine, spleen, stomach, testis, thymus, thyroid and uterus. Expressed in the alveolar epithelium of the lung. Expression is commonly decreased in colon adenocarcinomas and lung cancers.
Involvement in disease
Defects in TOPORS are the cause of retinitis pigmentosa type 31 (RP31) [MIM:609923]. RP leads to degeneration of retinal photoreceptor cells. Patients typically have night vision blindness and loss of midperipheral visual field. As their condition progresses, they lose their far peripheral visual field and eventually central vision as well. RP31 inheritance is autosomal dominant.
Contains 1 RING-type zinc finger.
Phosphorylation at Ser-98 regulates the E3 ubiquitin-protein ligase activity but not the SUMO1-protein ligase activity. Phosphorylation at Ser-718 increases the E3 ubiquitin-protein ligase activity versus the SUMO1-protein ligase activity resulting in increased p53/TP53 ubiquitination and degradation.
Nucleus. Nucleus > PML body. Localizes to discrete nuclear foci which partly overlap with PML nuclear bodies. Targeted to PML nuclear bodies upon DNA damage.
Information by UniProt
- AW105885 antibody
- E3 ubiquitin protein ligase Topors antibody
- E3 ubiquitin-protein ligase Topors antibody