Ubiquitin Specific Peptidase 22 (USP22)

USP22 contains 525 amino acids. It has an N-terminal zinc finger domain and a C-terminal ubiquitin hydrolase domain of the C19 class of peptidases.The deduced 593-amino acid protein shares significant identity with an S. pombe ubiquitin C-terminal hydrolase. The subunits of human SAGA that interacted with USP22 included TRRAP, ADA2 (TADA2L), ADA3 (TADA3L), TAF9L (TAF9B), TAF10, ATXN7, and the acetyltransferase GCN5 (KAT2A). Within SAGA, USP22 provided a deubiquitinating function and specifically deubiquitinated the core histone H2B. USP22 was required for transcriptional activation of specific MYC target genes, and depletion of USP22 compromised MYC functions, including cell transformation. Depletion of USP22 caused specific G1 cell cycle arrest.