title: Regulation of BRCC, a holoenzyme complex containing BRCA1 and BRCA2, by a signalosome-like subunit and its role in DNA repair.
abstract: We have isolated a holoenzyme complex termed BRCC containing BRCA1, BRCA2, and RAD51. BRCC not only displays increased association with p53 following DNA damage but also ubiquitinates p53 in vitro. BRCC36 and BRCC45 are novel components of the complex with sequence homology to a subunit of the signalosome and proteasome complexes. Reconstitution of a recombinant four-subunit complex containing BRCA1/BARD1/BRCC45/BRCC36 revealed an enhanced E3 ligase activity compared to that of BRCA1/BARD1 heterodimer. In vivo, depletion of BRCC36 and BRCC45 by the small interfering RNAs (siRNAs) resulted in increased sensitivity to ionizing radiation and defects in G2/M checkpoint. BRCC36 shows aberrant expression in sporadic breast tumors. These findings identify BRCC as a ubiquitin E3 ligase complex that enhances cellular survival following DNA damage.
authors.affiliation: The Wistar Institute, 3601 Spruce Street, Philadelphia, PA 19104, USA.
authors.forename: Yuanshu
authors.initials: Y
authors.lastname: Dong
authors.forename: Mohamed-Ali
authors.initials: MA
authors.lastname: Hakimi
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Chen
authors.forename: Easwari
authors.initials: E
authors.lastname: Kumaraswamy
authors.forename: Neil S
authors.initials: NS
authors.lastname: Cooch
authors.forename: Andrew K
authors.initials: AK
authors.lastname: Godwin
authors.forename: Ramin
authors.initials: R
authors.lastname: Shiekhattar
mesh_terms: D019313:BRCA1 Protein / Q000378:metabolism*; D024682:BRCA2 Protein / Q000378:metabolism*; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002453:Cell Cycle / Q000502:physiology; D002460:Cell Line; D004249:DNA Damage; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D006801:Humans; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes; D009419:Nerve Tissue Proteins / Q000378:metabolism; D021122:Protein Subunits / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000378:metabolism; D051135:Rad51 Recombinase; D011839:Radiation, Ionizing; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D025521:Tumor Suppressor Proteins; D025801:Ubiquitin / Q000378:metabolism; D044763:Ubiquitin-Conjugating Enzymes / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: C091514:BABAM2 protein, human; D019313:BRCA1 Protein; D024682:BRCA2 Protein; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D009097:Multienzyme Complexes; D009419:Nerve Tissue Proteins; D021122:Protein Subunits; D034741:RNA, Small Interfering; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; D025801:Ubiquitin; D044763:Ubiquitin-Conjugating Enzymes; C102449:BARD1 protein, human; D044767:Ubiquitin-Protein Ligases; C495153:RAD51 protein, human; D051135:Rad51 Recombinase