Probable ubiquitin carboxyl-terminal hydrolase FAF-Y (USP9Y)

May function as a ubiquitin-protein or polyubiquitin hydrolase involved both in the processing of ubiquitin precursors and of ubiquitinated proteins. May thus play an important regulatory role at the level of protein turnover by preventing degradation of proteins through the removal of conjugated ubiquitin.

Essential part of TGF-beta/BMP signaling cascade. Deubiquitinates monoubiquitinated SMAD4, opposing the activity of E3 ubiquitin-protein ligase TRIM33.