Ubiquitin Conjugating Enzyme E2E2 (UBE2E2)

The ubiquitin/proteasome system mediates a major pathway involved in selective protein degradation. In this pathway, the substrate proteins are first required to form a covalent bond with ubiquitin, a highly conserved 76-amino acid protein, before being targeted by a proteasome. Protein ubiquitination involves 3 classes of enzymes. At first, ubiquitin-activating enzyme (UBE1), encoded by a gene on the X chromosome, forms a thioester bond between the C-terminal glycine of ubiquitin and a cysteine residue of E1 in an ATP-dependent manner.

The bacterially expressed UBE2E2 protein formed an E1-dependent ubiquitin thioester. Fluorescence in situ hybridization experiments demonstrated that the gene is located on 3p24.2. The gene is homologous to yeast Ubc4/5.