title: Itch WW Domains Inhibit Its E3 Ubiquitin Ligase Activity by Blocking E2-E3 Ligase Trans-thiolation.
abstract: Nedd4-family E3 ubiquitin ligases regulate an array of biologic processes. Autoinhibition maintains these catalytic ligases in an inactive state through several mechanisms. However, although some Nedd4 family members are activated by binding to Nedd4 family-interacting proteins (Ndfips), how binding activates E3 function remains unclear. Our data reveal how these two regulatory processes are linked functionally. In the absence of Ndfip1, the Nedd4 family member Itch can bind an E2 but cannot accept ubiquitin onto its catalytic cysteine. This is because Itch is autoinhibited by an intramolecular interaction between its HECT (homologous to the E6-AP carboxy terminus domain) and two central WW domains. Ndfip1 binds these WW domains to release the HECT, allowing trans-thiolation and Itch catalytic activity. This molecular switch also regulates the closely related family member WWP2. Importantly, multiple PY motifs are required for Ndfip1 to activate Itch, functionally distinguishing Ndfips from single PY-containing substrates. These data establish a novel mechanism for control of the function of a subfamily of Nedd4 E3 ligases at the level of E2-E3 trans-thiolation.
authors.affiliation: From the Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104.
authors.forename: Christopher
authors.initials: C
authors.lastname: Riling
authors.affiliation: the St. Jude Children's Research Hospital, Memphis, Tennessee 38105.
authors.forename: Hari
authors.initials: H
authors.lastname: Kamadurai
authors.affiliation: Progenra Inc., Malvern, Pennsylvania 19355.
authors.forename: Suresh
authors.initials: S
authors.lastname: Kumar
authors.affiliation: From the Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104.
authors.forename: Claire E
authors.initials: CE
authors.lastname: O'Leary
authors.affiliation: the St. Jude Children's Research Hospital, Memphis, Tennessee 38105.
authors.forename: Kuen-Phon
authors.initials: KP
authors.lastname: Wu
authors.affiliation: Progenra Inc., Malvern, Pennsylvania 19355.
authors.forename: Erica E
authors.initials: EE
authors.lastname: Manion
authors.affiliation: the Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104.
authors.forename: Mingjie
authors.initials: M
authors.lastname: Ying
authors.affiliation: the St. Jude Children's Research Hospital, Memphis, Tennessee 38105, the Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, and.
authors.forename: Brenda A
authors.initials: BA
authors.lastname: Schulman
authors.affiliation: From the Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, the Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, the Department of Pathology and Laboratory Medicine, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104 paulao@mail.med.upenn.edu.
authors.forename: Paula M
authors.initials: PM
authors.lastname: Oliver
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D056827:Endosomal Sorting Complexes Required for Transport / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D019169:Jurkat Cells; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D000075702:Nedd4 Ubiquitin Protein Ligases; D017434:Protein Structure, Tertiary; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D056827:Endosomal Sorting Complexes Required for Transport; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C451223:NDFIP1 protein, human; C499188:Ndfip1 protein, mouse; D012097:Repressor Proteins; C432966:ITCH protein, human; C471637:Itch protein, mouse; D000075702:Nedd4 Ubiquitin Protein Ligases; C000618483:Nedd4 protein, human; C000618461:Nedd4l protein, mouse; C465283:WWP2 protein, human; C487995:Wwp2 protein, mouse; D044767:Ubiquitin-Protein Ligases
keywords: immunology; protein degradation; ubiquitin; ubiquitin ligase; ubiquitylation (ubiquitination)