E3 ubiquitin-protein ligase that mediates the polyubiquitination of a number of proteins such as CD3D, CYP3A4, CFTR and APOB for proteasomal degradation. Component of a VCP/p97- AMFR/gp78 complex that participates in the final step of endoplasmic reticulum-associated degradation (ERAD). The VCP/p97- AMFR/gp78 complex is involved in the sterol-accelerated ERAD degradation of HMGCR through binding to the HMGCR-INSIG complex at the ER membrane and initiating ubiquitination of HMGCR. The ubiquitinated HMGCR is then released from the ER by the complex into the cytosol for subsequent destruction. Also acts as a scaffold protein to assemble a complex that couples ubiquitination, retranslocation and deglycosylation. Mediates tumor invasion and metastasis. Interacts with RNF5. Also forms an ERAD complex containing VCP/p97, NGLY1; PSMC1; SAKS1 AND RAD23B required for coupling retrotranslocation, ubiquitination and deglycosylation. Interacts with DRL1. Interacts (through a region distinct from the RING finger) with UBE2G2/UBC7. Component of the VCP/p97-AMFR/gp78 complex that enhances VCP/p97 binding to polyubiquitinated proteins for their degradation by the endoplasmic reticulum-associated degradation (ERAD) pathway. Interacts (via the VIM) with VCP/p97. Interacts (via its membrane domain) with INSIG1; the interaction initiates the sterol-mediated ubiquitination and degradation of HMGCR by the ERAD pathway. 2 isoforms of the human protein are produced by alternative splicing. Note: This description may include information from UniProtKB.
Cellular Component: endoplasmic reticulum; endoplasmic reticulum membrane; Golgi apparatus; integral to endoplasmic reticulum membrane; membrane; perinuclear region of cytoplasm; protein complex
Molecular Function: chaperone binding; protein binding; protein binding, bridging; receptor activity; ubiquitin-protein ligase activity
Biological Process: cell motility; ER-associated protein catabolic process; positive regulation of protein binding; protein autoubiquitination; protein folding; protein oligomerization; protein polyubiquitination; protein ubiquitination during ubiquitin-dependent protein catabolic process; signal transduction; ubiquitin-dependent protein catabolic process; unfolded protein response