5ifr
From Proteopedia
Structure of the stable UBE2D3-UbDha conjugate
Structural highlights
Function[UB2D3_HUMAN] Accepts ubiquitin from the E1 complex and catalyzes its covalent attachment to other proteins. In vitro catalyzes 'Lys-11'-, as well as 'Lys-48'-linked polyubiquitination. Cooperates with the E2 CDC34 and the SCF(FBXW11) E3 ligase complex for the polyubiquitination of NFKBIA leading to its subsequent proteasomal degradation. Acts as an initiator E2, priming the phosphorylated NFKBIA target at positions 'Lys-21' and/or 'Lys-22' with a monoubiquitin. Ubiquitin chain elongation is then performed by CDC34, building ubiquitin chains from the UBE2D3-primed NFKBIA-linked ubiquitin. Acts also as an initiator E2, in conjunction with RNF8, for the priming of PCNA. Monoubiquitination of PCNA, and its subsequent polyubiquitination, are essential events in the operation of the DNA damage tolerance (DDT) pathway that is activated after DNA damage caused by UV or chemical agents during S-phase. Associates with the BRCA1/BARD1 E3 ligase complex to perform ubiquitination at DNA damage sites following ionizing radiation leading to DNA repair. Targets DAPK3 for ubiquitination which influences promyelocytic leukemia protein nuclear body (PML-NB) formation in the nucleus. In conjunction with the MDM2 and TOPORS E3 ligases, functions ubiquitination of p53/TP53. Supports NRDP1-mediated ubiquitination and degradation of ERBB3 and of BRUCE which triggers apoptosis. In conjunction with the CBL E3 ligase, targets EGFR for polyubiquitination at the plasma membrane as well as during its internalization and transport on endosomes. In conjunction with the STUB1 E3 quality control E3 ligase, ubiquitinates unfolded proteins to catalyze their immediate destruction (By similarity).[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [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.[15] [16] Publication Abstract from PubMedPost-translational modifications of proteins with ubiquitin (Ub) and ubiquitin-like modifiers (Ubls), orchestrated by a cascade of specialized E1, E2 and E3 enzymes, control a wide range of cellular processes. To monitor catalysis along these complex reaction pathways, we developed a cascading activity-based probe, UbDha. Similarly to the native Ub, upon ATP-dependent activation by the E1, UbDha can travel downstream to the E2 (and subsequently E3) enzymes through sequential trans-thioesterifications. Unlike the native Ub, at each step along the cascade, UbDha has the option to react irreversibly with active site cysteine residues of target enzymes, thus enabling their detection. We show that our cascading probe 'hops' and 'traps' catalytically active Ub-modifying enzymes (but not their substrates) by a mechanism diversifiable to Ubls. Our founder methodology, amenable to structural studies, proteome-wide profiling and monitoring of enzymatic activity in living cells, presents novel and versatile tools to interrogate Ub and Ubl cascades. A cascading activity-based probe sequentially targets E1-E2-E3 ubiquitin enzymes.,Mulder MP, Witting K, Berlin I, Pruneda JN, Wu KP, Chang JG, Merkx R, Bialas J, Groettrup M, Vertegaal AC, Schulman BA, Komander D, Neefjes J, El Oualid F, Ovaa H Nat Chem Biol. 2016 May 16. doi: 10.1038/nchembio.2084. PMID:27182664[17] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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