Ubiquitin Specific Peptidase 16 (USP16)

USP16 encodes a deubiquitinating enzyme that is phosphorylated at the onset of mitosis and then dephosphorylated at the metaphase/anaphase transition. It can deubiquitinate H2A, one of two major ubiquitinated proteins of chromatin, in vitro and a mutant form of the protein was shown to block cell division. Alternate transcriptional splice variants, encoding different isoforms, have been characterized.The 823-amino acid USP16 protein shares sequence similarities with other USPs and was shown to cleave standard substrates in vitro. Northern blot analysis detected a 3-kb transcript in all tissues tested. USP16 is maximally phosphorylated before metaphase and dephosphorylated in anaphase. Immunofluorescence microscopy showed that USP16 localizes to the cytoplasm and is expressed diffusely during mitosis.