A ubiquitin ligase is a protein that recruits an E2 ubiquitin-conjugating enzyme that has been loaded with ubiquitin, recognizes a protein substrate, and assists or directly catalyzes the transfer of ubiquitin from the E2 to the protein substrate. In simple and more general terms, the ligase enables movement of ubiquitin from a ubiquitin carrier to another thing by some mechanism. The ubiquitin, once it reaches its destination, ends up being attached by an isopeptide bond to a lysine residue, which is part of the target protein. E3 ligases interact with both the target protein and the E2 enzyme, and so impart substrate specificity to the E2. Commonly, E3s polyubiquitinate their substrate with Lys48-linked chains of ubiquitin, targeting the substrate for destruction by the proteasome. However, many other types of linkages are possible and alter a protein's activity, interactions, or localization. Ubiquitination by E3 ligases regulates diverse areas such as cell trafficking, DNA repair, and signaling and is of profound importance in cell biology. E3 ligases are also key players in cell cycle control, mediating the degradation of cyclins, as well as cyclin dependent kinase inhibitor proteins. The human genome encodes over 600 putative E3 ligases, allowing for tremendous diversity in substrates.
E3 ubiquitin-protein ligase CHFR is an enzyme that in humans is encoded by the CHFR gene.
E3 ubiquitin-protein ligase UBR5 is an enzyme that in humans is encoded by the UBR5 gene.
Ubiquitin-conjugating enzyme E2 G2 is a protein that in humans is encoded by the UBE2G2 gene.
NEDD8-activating enzyme E1 catalytic subunit is a protein that in humans is encoded by the UBA3 gene.
E3 ubiquitin-protein ligase RNF216 is an enzyme that in humans is encoded by the RNF216 gene.
Ubiquitin/ISG15-conjugating enzyme E2 L6 is a protein that in humans is encoded by the UBE2L6 gene.
ATP-dependent DNA helicase Q4 is an enzyme that in humans is encoded by the RECQL4 gene.
The human gene UBR1 encodes the enzyme ubiquitin-protein ligase E3 component n-recognin 1.
Ubiquitin-conjugating enzyme E2 B is a protein that in humans is encoded by the UBE2B gene.
E3 ubiquitin-protein ligase FANCL is an enzyme that in humans is encoded by the FANCL gene.
E3 ubiquitin-protein ligase RNF123 is an enzyme that in humans is encoded by the RNF123 gene.
Ubiquitin thioesterase OTUB1 also known as otubain-1 is an enzyme that in humans is encoded by the OTUB1 gene. Alternative splicing results in multiple transcript variants.
Ubiquitin-conjugating enzyme E2 H is a protein that in humans is encoded by the UBE2H gene.
Ubiquitin carboxyl-terminal hydrolase 15 is an enzyme that in humans is encoded by the USP15 gene.
E3 ubiquitin-protein ligase UBR4 is an enzyme that in humans is encoded by the UBR4 gene.
Ubiquitin-fold modifier 1, also known as UFM1, is a protein which in humans is encoded by the UFM1 gene.
E3 ubiquitin-protein ligase UHRF2 is an enzyme that in humans is encoded by the UHRF2 gene.
E3 ubiquitin-protein ligase RNF125 is an enzyme that in humans is encoded by the RNF125 gene.
Johanson–Blizzard syndrome is a rare, sometimes fatal autosomal recessive multisystem congenital disorder featuring abnormal development of the pancreas, nose and scalp, with intellectual disability, hearing loss and growth failure. It is sometimes described as a form of ectodermal dysplasia.
