6dgf | pdb_00006dgf
Ubiquitin Variant bound to USP2
Structural highlights
Function[UBP2_HUMAN] Hydrolase that deubiquitinates polyubiquitinated target proteins such as MDM2, MDM4 and CCND1. Isoform 1 and isoform 4 possess both ubiquitin-specific peptidase and isopeptidase activities. Deubiquitinates MDM2 without reversing MDM2-mediated p53/TP53 ubiquitination and thus indirectly promotes p53/TP53 degradation and limits p53 activity. Has no deubiquitinase activity against p53/TP53. Prevents MDM2-mediated degradation of MDM4. Plays a role in the G1/S cell-cycle progression in normal and cancer cells. Plays a role in the regulation of myogenic differentiation of embryonic muscle cells.[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] Publication Abstract from PubMedWe applied a yeast-two-hybrid (Y2H) analysis to screen for ubiquitin variant (UbV) inhibitors of a human deubiquitinase (DUB), ubiquitin-specific protease 2 (USP2). The Y2H screen used USP2 as the bait and a prey library consisting of UbVs randomized at four specific positions, which were known to interact with USP2 from phage display analysis. The screen yielded numerous UbVs that bound to USP2 both as a Y2H interaction in vivo and as purified proteins in vitro. The Y2H-derived UbVs inhibited the catalytic activity of USP2 in vitro with nanomolar-range potencies, and they bound and inhibited USP2 in human cells. Mutational and structural analysis showed that potent and selective inhibition could be achieved by just two substitutions in a UbV, which exhibited improved hydrophobic and hydrophilic contacts compared to the wild-type ubiquitin interaction with USP2. Our results establish Y2H as an effective platform for the development of UbV inhibitors of DUBs in vivo, providing an alternative strategy for the analysis of DUBs that are recalcitrant to phage display and other in vitro methods. Yeast Two-Hybrid Analysis for Ubiquitin Variant Inhibitors of Human Deubiquitinases.,Pascoe N, Seetharaman A, Teyra J, Manczyk N, Satori MA, Tjandra D, Makhnevych T, Schwerdtfeger C, Brasher BB, Moffat J, Costanzo M, Boone C, Sicheri F, Sidhu SS J Mol Biol. 2019 Mar 15;431(6):1160-1171. doi: 10.1016/j.jmb.2019.02.007. Epub, 2019 Feb 11. PMID:30763569[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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