The nuclear envelope is a membrane system which surrounds the nucleoplasm of eukaryotic cells. It is composed of the nuclear lamina, nuclear pore complexes and two nuclear membranes. The space between the two membranes is called the nuclear intermembrane space.
The inner membrane of the nucleus is the membrane which separates the nuclear matrix from the intermembrane space. In mammals, the inner nuclear membrane is associated with heterochromatin and the nuclear lamina.
The membrane surrounding the nucleus. This term is used when it is not known if the protein is found in or associated with the inner or outer nuclear membrane.
E3 ubiquitin-protein ligase which accepts ubiquitin specifically from endoplasmic reticulum-associated UBC6 and UBC7 E2 ligases, and transfers it to substrates promoting their degradation (PubMed:11641273, PubMed:16179952, PubMed:16437165, PubMed:16873066, PubMed:17051211, PubMed:18812321, PubMed:20110468). Mediates the degradation of a broad range of substrates, including endoplasmic reticulum membrane proteins (ERQC), soluble nuclear proteins and soluble cytoplasmic proteins (CytoQC) (PubMed:11641273, PubMed:16179952, PubMed:16437165, PubMed:16873066, PubMed:17051211, PubMed:18812321, PubMed:20110468). Component of the DOA10 ubiquitin ligase complex, which is part of the ERAD-C pathway responsible for the rapid degradation of membrane proteins with misfolded cytoplasmic domains (PubMed:16873066). ERAD-C substrates are ubiquitinated through DOA10 in conjunction with the E2 ubiquitin-conjugating enzymes UBC6 and UBC7-CUE1 (PubMed:11641273, PubMed:16179952, PubMed:16437165, PubMed:16873066, PubMed:17051211, PubMed:18812321, PubMed:20110468). Ubiquitinated substrates are then removed to the cytosol via the action of the UFD1-NPL4-CDC48/p97 (UNC) AAA ATPase complex and targeted to the proteasome (PubMed:11641273, PubMed:16179952, PubMed:16437165, PubMed:16873066, PubMed:17051211, PubMed:18812321, PubMed:20110468). Also recognizes the N-terminally acetylated residue of proteins as degradation signal (degron) (PubMed:20110468). N-terminally acetylated target proteins include MATALPHA2, TBF1, SLK19, YMR090W, HIS3, HSP104, UBP6 and ARO8 (PubMed:20110468). Catalyzes ubiquitination of mislocalized tail-anchored proteins that are extracted from the mitochondrion membrane by MSP1: following extraction, mistargeted proteins are transferred to the endoplasmic reticulum, where they are ubiquitinated by DOA10 and degraded by the proteasome (PubMed:31445887). {Experimental EvidencePubMed:11641273, Experimental EvidencePubMed:16179952, Experimental EvidencePubMed:16437165, Experimental EvidencePubMed:16873066, Experimental EvidencePubMed:17051211, Experimental EvidencePubMed:18812321, Experimental EvidencePubMed:20110468, Experimental EvidencePubMed:31445887}.
National and Kapodistrian University of Athens
Department of Biology
Biophysics & Bioinformatics Laboratory