5cvn
From Proteopedia
WDR48 (2-580):USP46~ubiquitin ternary complex
Structural highlights
Disease[WDR48_HUMAN] Autosomal recessive spastic paraplegia type 60. Function[WDR48_HUMAN] Regulator of deubiquitinating complexes. Acts as a strong activator of USP1 by enhancing the USP1-mediated deubiquitination of FANCD2; USP1 being almost inactive by itself. Also activates deubiquitinating activity of complexes containing USP12 and USP46, respectively. Activates deubiquitination by increasing the catalytic turnover without increasing the affinity of deubiquitinating enzymes for the substrate. In case of infection by Herpesvirus saimiri, may play a role in vesicular transport or membrane fusion events necessary for transport to lysosomes. Induces lysosomal vesicle formation via interaction with Herpesvirus saimiri tyrosine kinase-interacting protein (TIP). Subsequently, TIP recruits tyrosine-protein kinase LCK, resulting in down-regulation of T-cell antigen receptor TCR. May play a role in generation of enlarged endosomal vesicles via interaction with TIP. In case of infection by papillomavirus HPV11, promotes the maintenance of the viral genome via its interaction with HPV11 helicase E1.[1] [2] [3] [UBB_HUMAN] Ubiquitin exists either covalently attached to another protein, or free (unanchored). When covalently bound, it is conjugated to target proteins via an isopeptide bond either as a monomer (monoubiquitin), a polymer linked via different Lys residues of the ubiquitin (polyubiquitin chains) or a linear polymer linked via the initiator Met of the ubiquitin (linear polyubiquitin chains). Polyubiquitin chains, when attached to a target protein, have different functions depending on the Lys residue of the ubiquitin that is linked: Lys-6-linked may be involved in DNA repair; Lys-11-linked is involved in ERAD (endoplasmic reticulum-associated degradation) and in cell-cycle regulation; Lys-29-linked is involved in lysosomal degradation; Lys-33-linked is involved in kinase modification; Lys-48-linked is involved in protein degradation via the proteasome; Lys-63-linked is involved in endocytosis, DNA-damage responses as well as in signaling processes leading to activation of the transcription factor NF-kappa-B. Linear polymer chains formed via attachment by the initiator Met lead to cell signaling. Ubiquitin is usually conjugated to Lys residues of target proteins, however, in rare cases, conjugation to Cys or Ser residues has been observed. When polyubiquitin is free (unanchored-polyubiquitin), it also has distinct roles, such as in activation of protein kinases, and in signaling.[4] [5] [UBP46_HUMAN] Deubiquitinating enzyme that plays a role in behavior, possibly by regulating GABA action. May act by mediating the deubiquitination of GAD1/GAD67. Has almost no deubiquitinating activity by itself and requires the interaction with WDR48 to have a high activity. Not involved in deubiquitination of monoubiquitinated FANCD2.[6] Publication Abstract from PubMedProtein ubiquitination patterns are an important component of cellular signaling. The WD-repeat protein WDR48 (USP1-associated factor UAF-1) stimulates activity of ubiquitin-specific proteases USP1, USP12, and USP46. To understand how WDR48 exerts its effect on the USP scaffold, we determined structures of the ternary WDR48:USP46:ubiquitin complex. WDR48 interacts with the USP46 fingers subdomain via a relatively small, highly polar surface on the top center of the WDR48 beta propeller. In addition, WDR48 has a novel ancillary domain and a C-terminal SUMO-like domain encircling the USP46-bound ubiquitin. Mutation of residues involved in the WDR48:USP46 interaction abrogated both binding and deubiquitinase activity of the complex. An analogous mutation in USP1 similarly blocked WDR48-dependent activation. Our data suggest a possible mechanism of deubiquitinase stimulation via stabilization and prolonged residence time of substrate. The unprecedented mode of interaction between the USP fingers domain and the WD-repeat beta propeller serves as a prototypical example for this family of deubiquitinases. Structural Insights into WD-Repeat 48 Activation of Ubiquitin-Specific Protease 46.,Yin J, Schoeffler AJ, Wickliffe K, Newton K, Starovasnik MA, Dueber EC, Harris SF Structure. 2015 Sep 12. pii: S0969-2126(15)00359-7. doi:, 10.1016/j.str.2015.08.010. PMID:26388029[7] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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