3tmp
From Proteopedia
The catalytic domain of human deubiquitinase DUBA in complex with ubiquitin aldehyde
Structural highlights
Function[OTUD5_HUMAN] Deubiquitinating enzyme that functions as negative regulator of the innate immune system. Acts via TRAF3 deubiquitination and subsequent suppression of type I interferon (IFN) production. Has peptidase activity towards 'Lys-48'- and 'Lys-63'-linked polyubiquitin chains. Can also cleave 'Lys-11'-linked ubiquitin chains (in vitro).[1] [2] [UBC_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.[3] [4] Publication Abstract from PubMedAddition and removal of ubiquitin or ubiquitin chains to and from proteins is a tightly regulated process that contributes to cellular signaling and protein stability. Here we show that phosphorylation of the human deubiquitinase DUBA (OTUD5) at a single residue, Ser177, is both necessary and sufficient to activate the enzyme. The crystal structure of the ubiquitin aldehyde adduct of active DUBA reveals a marked cooperation between phosphorylation and substrate binding. An intricate web of interactions involving the phosphate and the C-terminal tail of ubiquitin cause DUBA to fold around its substrate, revealing why phosphorylation is essential for deubiquitinase activity. Phosphoactivation of DUBA represents an unprecedented mode of protease regulation and a clear link between two major cellular signal transduction systems: phosphorylation and ubiquitin modification. Phosphorylation-dependent activity of the deubiquitinase DUBA.,Huang OW, Ma X, Yin J, Flinders J, Maurer T, Kayagaki N, Phung Q, Bosanac I, Arnott D, Dixit VM, Hymowitz SG, Starovasnik MA, Cochran AG Nat Struct Mol Biol. 2012 Jan 15;19(2):171-5. doi: 10.1038/nsmb.2206. PMID:22245969[5] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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