ubiquitin carboxyl-terminal hydrolase FAF-Y; deubiquitinating enzyme FAF-Y; fat facets protein-related, Y-linked; ubiquitin thiolesterase FAF-Y; ubiquitin-specific protease 9, Y chromosome; ubiquitin-specific-processing protease FAF-Y (USP9Y, DFFRY)

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Function

may function as a ubiquitin-protein or polyubiquitin hydrolase involved both in the processing of ubiquitin precursors & of ubiquitinated proteins
may play a regulatory role by preventing degradation of proteins through the removal of conjugated ubiquitin
essential component of TGF-beta/BMP signaling cascade
- deubiquitinates monoubiquitinated SMAD4, opposing the activity of E3 ubiquitin-protein ligase TRIM33
- monoubiquitination of SMAD4 hampers its ability to form a stable complex with activated SMAD2/3 resulting in inhibition of TGF- beta/BMP signaling cascade.
- deubiqitination of SMAD4 by USP9X re-empowers its competence to mediate TGF-beta signaling
thiol-dependent hydrolysis of ester, thioester, amide, peptide & isopeptide bonds formed by the C-terminal Gly of ubiquitin (a 76-residue protein attached to proteins as an intracellular targeting signal)
interacts with SMAD4 (putative)

belongs to the peptidase C19 family

named isoforms=2
additional isoforms seem to exist
at least one isoform may be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay

USP9Y is located in the 'azoospermia factor a' (AZFa) region on chromosome Y which is deleted in Sertoli-cell-only syndrome
defects in USP9Y might be a cause of spermatogenic failure non-obstructive Y-linked
the role of USP9Y in spermatogenesis failure is uncertain
absence of USP9Y found in a man with normal sperm