title: Characterizing WW domain interactions of tumor suppressor WWOX reveals its association with multiprotein networks.
abstract: WW domains are small modules present in regulatory and signaling proteins that mediate specific protein-protein interactions. The WW domain-containing oxidoreductase (WWOX) encodes a 46-kDa tumor suppressor that contains two N-terminal WW domains and a central short-chain dehydrogenase/reductase domain. Based on its ligand recognition motifs, the WW domain family is classified into four groups. The largest one, to which WWOX belongs, recognizes ligands with a PPXY motif. To pursue the functional properties of the WW domains of WWOX, we employed mass spectrometry and phage display experiments to identify putative WWOX-interacting partners. Our analysis revealed that the first WW (WW1) domain of WWOX is the main functional interacting domain. Furthermore, our study uncovered well known and new PPXY-WW1-interacting partners and shed light on novel LPXY-WW1-interacting partners of WWOX. Many of these proteins are components of multiprotein complexes involved in molecular processes, including transcription, RNA processing, tight junction, and metabolism. By utilizing GST pull-down and immunoprecipitation assays, we validated that WWOX is a substrate of the E3 ubiquitin ligase ITCH, which contains two LPXY motifs. We found that ITCH mediates Lys-63-linked polyubiquitination of WWOX, leading to its nuclear localization and increased cell death. Our data suggest that the WW1 domain of WWOX provides a versatile platform that links WWOX with individual proteins associated with physiologically important networks.
authors.affiliation: From the Lautenberg Center for Immunology and Cancer Research, IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel 91120.
authors.forename: Mohammad
authors.initials: M
authors.lastname: Abu-Odeh
authors.forename: Tomer
authors.initials: T
authors.lastname: Bar-Mag
authors.forename: Haiming
authors.initials: H
authors.lastname: Huang
authors.forename: TaeHyung
authors.initials: T
authors.lastname: Kim
authors.forename: Zaidoun
authors.initials: Z
authors.lastname: Salah
authors.forename: Suhaib K
authors.initials: SK
authors.lastname: Abdeen
authors.forename: Marius
authors.initials: M
authors.lastname: Sudol
authors.forename: Dana
authors.initials: D
authors.lastname: Reichmann
authors.forename: Sachdev
authors.initials: S
authors.lastname: Sidhu
authors.forename: Philip M
authors.initials: PM
authors.lastname: Kim
authors.forename: Rami I
authors.initials: RI
authors.lastname: Aqeilan
mesh_terms: D020816:Amino Acid Motifs; D057809:HEK293 Cells; D006801:Humans; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism*; D019151:Peptide Library; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D025521:Tumor Suppressor Proteins / Q000737:chemistry* / Q000378:metabolism*; D054875:Ubiquitination; D000074584:WW Domain-Containing Oxidoreductase
chemical_list: D019151:Peptide Library; D011993:Recombinant Fusion Proteins; D025521:Tumor Suppressor Proteins; D010088:Oxidoreductases; D000074584:WW Domain-Containing Oxidoreductase; C486071:WWOX protein, human
keywords: E3 Ubiquitin Ligase; Itch; Mass Spectrometry (MS); Protein-Protein Interactions; Tumor Suppressor Gene; Ubiquitination; WW Domain; WWOX