| Modification Notes |
In eukaryotes, degradation of damaged or excess proteins into short peptides is carried out by proteasomes. The proteasomes bind polyubiquitin chains that are added to the target proteins through a phosphorylation-dependent reaction catalyzed by ubiquitin ligases, such as the SCF-type E3 complex containing Skp, Cullin, Rbx1 and F-box proteins. F-box proteins, such as FBXO27 (F-box only protein 27), possess structural motifs used for directly aggregating the substrate while binding to the Skp1 bridge providing for close proximity to the functional E2 ubiquitin-conjugating enzyme, Cullin/Rbx1. FBXO27, also known as FBG5 and FBX27, is a 283 amino acid protein that contains an N-terminal F-box and a C-terminal F-box-associated domain. FBXO27 found highly expressed in brain, heart and kidney with lower levels found in kidney and liver. |