A RING finger-containing protein (AO7) that binds ubiquitin-conjugating enzymes (E2s) and is a substrate for E2-dependent ubiquitination was identified. Mutations of cation-coordinating residues within AO7's RING finger abolished ubiquitination, as did chelation of zinc. Several otherwise-unrelated RING finger proteins, including BRCA1, Siah-1, TRC8, NF-X1, kf-1, and Praja1, were assessed for their ability to facilitate E2-dependent ubiquitination. In all cases, ubiquitination was observed. The RING fingers were implicated directly in this activity through mutations of metal-coordinating residues or chelation of zinc. These findings suggest that a large number of RING finger-containing proteins, with otherwise diverse structures and functions, may play previously unappreciated roles in modulating protein levels via ubiquitination.
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http://dx.doi.org/10.1073/pnas.96.20.11364 | DOI Listing |
Methods Mol Biol
May 2019
Department of Molecular Biosciences, University of Texas at Austin, Austin, TX, USA.
UBAITs (Ubiquitin-Activated Interaction Traps) are reagents that capitalize on the biochemistry of the ubiquitin system to covalently trap transient protein-protein interactions. UBAITs consist of an affinity-tagged protein of interest fused to a short linker followed by a C-terminal ubiquitin moiety. When charged in an E1- and E2-dependent manner, the C-terminal ubiquitin moiety of the UBAIT has the potential to form an amide linkage with lysine side chains of a protein that interacts transiently with the protein of interest, thereby covalently trapping the protein-protein interaction.
View Article and Find Full Text PDFAutophagy
June 2019
a Key Laboratory of Systems Biology , CAS Center for Excellence in Molecular Cell Science , Innovation Center for Cell Signaling Network, Shanghai , China.
The alterations in cellular ubiquitin (Ub) homeostasis, known as Ub stress, feature and affect cellular responses in multiple conditions, yet the underlying mechanisms are incompletely understood. We recently reported that the macroautophagy/autophagy receptor SQSTM1/p62, functions as a novel Ub sensor to activate autophagy upon Ub stress (upregulation of the Ub level). First, SQSTM1 was found to undergo extensive ubiquitination and activate autophagy under Ub stress induced by prolonged Bortezomib (BTZ) treatment, Ub overexpression or by heat shock.
View Article and Find Full Text PDFCell Res
May 2017
Key Laboratory of Systems Biology, CAS Center for Excellence in Molecular Cell Science, Innovation Center for Cell Signaling Network, Shanghai 200031, China.
Alterations in cellular ubiquitin (Ub) homeostasis, known as Ub stress, feature and affect cellular responses in multiple conditions, yet the underlying mechanisms are incompletely understood. Here we report that autophagy receptor p62/sequestosome-1 interacts with E2 Ub conjugating enzymes, UBE2D2 and UBE2D3. Endogenous p62 undergoes E2-dependent ubiquitylation during upregulation of Ub homeostasis, a condition termed as Ub stress, that is intrinsic to Ub overexpression, heat shock or prolonged proteasomal inhibition by bortezomib, a chemotherapeutic drug.
View Article and Find Full Text PDFEMBO Rep
December 2015
Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX, USA
We describe a new class of reagents for identifying substrates, adaptors, and regulators of HECT and RING E3s. UBAITs (Ubiquitin-Activated Interaction Traps) are E3-ubiquitin fusion proteins and, in an E1- and E2-dependent manner, the C-terminal ubiquitin moiety forms an amide linkage to proteins that interact with the E3, enabling covalent co-purification of the E3 with partner proteins. We designed UBAITs for both HECT (Rsp5, Itch) and RING (Psh1, RNF126, RNF168) E3s.
View Article and Find Full Text PDFCell Signal
December 2015
Department of Science, Section Biomedical Sciences and Technology, University Roma Tre, Viale Guglielmo Marconi, 446, I-00146 Rome, Italy. Electronic address:
17β-Estradiol (E2)-dependent cell proliferation requires both estrogen receptor α (ERα)-based integrated control of gene transcription and kinase pathways activation. Such coordination of intracellular E2:ERα-dependent signaling mechanisms is finely tuned by receptor association with specific partner proteins. Recently, we identified the leucine (L) 429 and alanine (A) 430 within the ERα ligand binding domain as important residues for receptor non-covalent interaction to ubiquitinated species [i.
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