E3 ligases confer specificity to ubiquitination by recognizing target substrates and mediating transfer of ubiquitin from an E2 ubiquitin-conjugating enzyme to substrate. The activity of most E3s is specified by a RING domain, which binds to an E2 approximately ubiquitin thioester and activates discharge of its ubiquitin cargo. E2-E3 complexes can either monoubiquitinate a substrate lysine or s...

To maintain cholesterol homeostasis, the processes of cholesterol metabolism are regulated at multiple levels including transcription, translation, and enzymatic activity. Recently, the regulation of protein stability of some key players in cholesterol metabolism has been characterized. More and more ubiquitin ligases have been identified including gp78, Hrd1, TRC8, TEB4, Fbw7, and inducible de...

Copyright © 2015 Frédéric Pecorari et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Many industrial/biotechnological processes take place under extreme conditions of temperature, pH, salinity, or pressure which are not suita...

Melanoma antigen L2 (MAGE-L2) belongs to the approximately 60 gene MAGE family, which is divided into two subsets based on chromosomal location and expression pattern. MAGE proteins act as ubiquitin ligase regulators in conjunction with E3 RING ubiquitin ligases to form MAGE-RING ligases (MRLs). MAGEL2 has elevated expression in the hypothalamus and functions within a multi-subunit protein comp...

Ubiquitination is known to be important for endocytosis and lysosomal degradation of aquaporin-2 (AQP2). Ubiquitin (Ub) is covalently attached to the lysine residue of the substrate proteins and activation and attachment of Ub to a target protein is mediated by the action of three enzymes (i.e., E1, E2, and E3). In particular, E3 Ub-protein ligases are known to have substrate specificity. This ...

COP9 Signalosome (CSN) is a fascinating protein complex whose biochemical and physiological functions are only beginning to be understood. It is conserved throughout eukaryotes and is critical to the proper development of all multicellular organisms in which its function has been explored. Recent work suggests that CSN plays a key role in sustaining the activity of SCF and other cullin-based ub...