USP9x: ProductsUbiquitin Specific Peptidase 9, X-linked (USP9x), also known as DFFRX, FAF, and FAM, is a cytoplasmic protein that belongs to the peptidase C19 family of deubiquitinating enzymes. It is 2570 amino acids (aa) in length with a predicted molecular weight of 292.3 kDa. Human USP9x shares 98% aa sequence identity with the mouse and rat orthologs. USP9x contains a catalytic domain located between aa 1531 and 1971 and a Ubiquitin-like domain that is located at aa 873-963. It is widely expressed and has been shown to interact with and deubiquitinate multiple substrates. Some putative targets include beta-Catenin, TOR, Synuclein-alpha, the Ubiquitin ligases (E3s) Itch, MARCH7, and SMURF1, and the MAP kinase kinase kinase ASK1. USP9x has also been shown to control the activity of the AMPK-related kinases ARK5 and MARK4 through direct removal of Lys29- and Lys33-linked Ubiquitin chains. It has also been shown to promote cell survival by deubiquitinating and stabilizing the anti-apoptotic protein Mcl-1, and to regulate chromosome alignment and segregation during mitosis by deubiquitinating the chromosome passenger protein Survivin. Additionally, USP9x appears to promote TGF-beta signaling via deubiquitination of mono-ubiquitinated Smad4. USP9x expression has been shown to be correlated with several cancer types.