E3 ubiquitin-protein ligase synoviolin (Syvn1)

Acts as an E3 ubiquitin-protein ligase which accepts ubiquitin especially from endoplasmic reticulum-associated UBC7 E2 ligase and transfers it to substrates, promoting their degradation (PubMed:12975321, PubMed:15611074). Component of the endoplasmic reticulum quality control (ERQC) system also called ER-associated degradation (ERAD) involved in ubiquitin-dependent degradation of misfolded endoplasmic reticulum proteins (PubMed:12975321, PubMed:15611074).

Also promotes the degradation of normal but naturally short-lived proteins such as SGK. Sequesters p53/TP53 in the cytoplasm and promotes its degradation, thereby negatively regulating its biological role in transcription, cell cycle regulation and apoptosis (PubMed:17170702).