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Title: Binding and Recognition in the Assembly of an Active BRCA1/BARD1 Ubiquitin-Ligase Complex

Abstract

BRCA1 is a breast and ovarian cancer tumor suppressor protein that associates with BARD1 to form a RING/RING heterodimer. The BRCA1/BARD1 RING complex functions as an ubiquitin (Ub) ligase with activity substantially greater than individual BRCA1 or BARD1 subunits. By using NMR spectroscopy and site-directed mutagenesis, we have mapped the binding site on the BRCA1/BARD1 heterodimer for the Ub-conjugating enzyme UbcH5c. The results demonstrate that UbcH5c binds only to the BRCA1 RING domain and not the BARD1 RING. The binding interface is formed by the first and second Zn2+-loops and central -helix of the BRCA1 RING domain, a region disrupted by cancer-predisposing mutations. Unexpectedly, a second Ub-conjugating enzyme, UbcH7, also interacts with the BRCA1/BARD1 complex with similar affinity, although it is not active in Ub-ligase activity assays. Thus, binding alone is not sufficient for BRCA1-dependent Ub-ligase activity.

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Lab. (PNNL), Richland, WA (United States). Environmental Molecular Sciences Lab. (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
15005616
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Proceedings of the National Academy of Sciences of the United States of America, 100(10):5646-5651
Additional Journal Information:
Journal Volume: 100; Journal Issue: 10
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; AFFINITY; ENZYMES; LIGASES; MAMMARY GLANDS; MUTAGENESIS; MUTATIONS; NEOPLASMS; PROTEINS; SPECTROSCOPY; Environmental Molecular Sciences Laboratory

Citation Formats

Brzovic, Peter S., Keeffe, Jennifer R., Nishikawa, Hiroyuki, Miyamoto, Keiko, Fox, David, Fukuda, Mamoru, Ohta, Tomohiko, and Klevit, Rachel E. Binding and Recognition in the Assembly of an Active BRCA1/BARD1 Ubiquitin-Ligase Complex. United States: N. p., 2003. Web. doi:10.1073/pnas.0836054100.
Brzovic, Peter S., Keeffe, Jennifer R., Nishikawa, Hiroyuki, Miyamoto, Keiko, Fox, David, Fukuda, Mamoru, Ohta, Tomohiko, & Klevit, Rachel E. Binding and Recognition in the Assembly of an Active BRCA1/BARD1 Ubiquitin-Ligase Complex. United States. https://doi.org/10.1073/pnas.0836054100
Brzovic, Peter S., Keeffe, Jennifer R., Nishikawa, Hiroyuki, Miyamoto, Keiko, Fox, David, Fukuda, Mamoru, Ohta, Tomohiko, and Klevit, Rachel E. 2003. "Binding and Recognition in the Assembly of an Active BRCA1/BARD1 Ubiquitin-Ligase Complex". United States. https://doi.org/10.1073/pnas.0836054100.
@article{osti_15005616,
title = {Binding and Recognition in the Assembly of an Active BRCA1/BARD1 Ubiquitin-Ligase Complex},
author = {Brzovic, Peter S. and Keeffe, Jennifer R. and Nishikawa, Hiroyuki and Miyamoto, Keiko and Fox, David and Fukuda, Mamoru and Ohta, Tomohiko and Klevit, Rachel E.},
abstractNote = {BRCA1 is a breast and ovarian cancer tumor suppressor protein that associates with BARD1 to form a RING/RING heterodimer. The BRCA1/BARD1 RING complex functions as an ubiquitin (Ub) ligase with activity substantially greater than individual BRCA1 or BARD1 subunits. By using NMR spectroscopy and site-directed mutagenesis, we have mapped the binding site on the BRCA1/BARD1 heterodimer for the Ub-conjugating enzyme UbcH5c. The results demonstrate that UbcH5c binds only to the BRCA1 RING domain and not the BARD1 RING. The binding interface is formed by the first and second Zn2+-loops and central -helix of the BRCA1 RING domain, a region disrupted by cancer-predisposing mutations. Unexpectedly, a second Ub-conjugating enzyme, UbcH7, also interacts with the BRCA1/BARD1 complex with similar affinity, although it is not active in Ub-ligase activity assays. Thus, binding alone is not sufficient for BRCA1-dependent Ub-ligase activity.},
doi = {10.1073/pnas.0836054100},
url = {https://www.osti.gov/biblio/15005616}, journal = {Proceedings of the National Academy of Sciences of the United States of America, 100(10):5646-5651},
number = 10,
volume = 100,
place = {United States},
year = {Tue May 13 00:00:00 EDT 2003},
month = {Tue May 13 00:00:00 EDT 2003}
}