BRCA1 Blocking Peptide

This gene encodes a nuclear phosphoprotein that plays a role in maintaining genomic stability, and it also acts as a tumor suppressor. The encoded protein combines with other tumor suppressors, DNA damage sensors, and signal transducers to form a large multi-subunit protein complex known as the BRCA1-associated genome surveillance complex (BASC). This gene product associates with RNA polymerase II, and through the C-terminal domain, also interacts with histone deacetylase complexes. This protein thus plays a role in transcription, DNA repair of double-stranded breaks, and recombination. Mutations in this gene are responsible for approximately 40% of inherited breast cancers and more than 80% of inherited breast and ovarian cancers. Alternative splicing plays a role in modulating the subcellular localization and physiological function of this gene. Many alternatively spliced transcript variants, some of which are disease-associated mutations, have been described for this gene, but the full-length natures of only some of these variants has been described. A related pseudogene, which is also located on chromosome 17, has been identified. [provided by RefSeq, May 2009]

BRCA1: the BRCA1-BARD1 heterodimer coordinates a diverse range of cellular pathways such as DNA damage repair, ubiquitination and transcriptional regulation to maintain genomic stability. Acts by mediating ubiquitin E3 ligase activity that is required for its tumor suppressor function. Plays a central role in DNA repair by facilitating cellular response to DNA repair. Required for appropriate cell cycle arrests after ionizing irradiation in both the S-phase and the G2 phase of the cell cycle. Involved in transcriptional regulation of P21 in response to DNA damage. Required for FANCD2 targeting to sites of DNA damage. May function as a transcriptional regulator. Inhibits lipid synthesis by binding to inactive phosphorylated ACC1 and preventing its dephosphorylation. Defects in BRCA1 are a cause of genetic susceptibility to breast cancer. Mutations in BRCA1 are thought to be responsible for more than 80% of inherited breast-ovarian cancer. Part of the BRCA1-associated genome surveillance complex (BASC), which contains BRCA1, MSH2, MSH6, MLH1, ATM, BLM, PMS2 and the RAD50-MRE11-NBN protein complex. This association may be a dynamic process changing throughout the cell cycle and within subnuclear domains. Interacts (via BRCT domains) with CTIP. Associates with RNA polymerase II holoenzyme. Interacts with SMC1 and COBRA1. Interacts (via BRCT domains) with BRIP1. Interacts with FANCD2 (ubiquitinated). Interacts with BAP1. Interacts with Artemis and claspin. Interacts with H2AFX (phosphorylated on S140). Interacts with CHK1. Interacts with BRCC3. Five human isoforms are produced by alternative splicing and alternative initiation. Isoform 1 and isoform 3 are widely expressed. Isoform 1 is largely nuclear, while isoforms 3 and 5 are cytoplasmic.

Protein type: Ubiquitin conjugating system; Nuclear receptor co-regulator; Transcription, coactivator/corepressor; EC 6.3.2.-; Tumor suppressor; Ubiquitin ligase

Chromosomal Location of Human Ortholog: 17q21

Cellular Component: nucleoplasm; gamma-tubulin ring complex; condensed nuclear chromosome; protein complex; cytoplasm; BRCA1-BARD1 complex; plasma membrane; chromosome; nucleus; ribonucleoprotein complex; ubiquitin ligase complex

Molecular Function: tubulin binding; protein binding; enzyme binding; DNA binding; androgen receptor binding; zinc ion binding; RNA binding; ubiquitin protein ligase binding; transcription coactivator activity; ubiquitin-protein ligase activity; damaged DNA binding; ligase activity

Biological Process: genetic imprinting; apoptosis; positive regulation of transcription, DNA-dependent; dosage compensation, by inactivation of X chromosome; centrosome cycle; protein ubiquitination; negative regulation of histone H3-K4 methylation; positive regulation of histone H3-K4 methylation; chromosome segregation; negative regulation of histone acetylation; regulation of apoptosis; DNA damage response, signal transduction by p53 class mediator resulting in transcription of p21 class mediator; double-strand break repair; DNA replication; negative regulation of fatty acid biosynthetic process; fatty acid biosynthetic process; negative regulation of histone H3-K9 methylation; positive regulation of histone H3-K9 methylation; protein autoubiquitination; positive regulation of DNA repair; chordate embryonic development; postreplication repair; DNA repair; negative regulation of centriole replication; double-strand break repair via homologous recombination; regulation of cell proliferation; regulation of transcription from RNA polymerase II promoter; positive regulation of angiogenesis; DNA damage response, signal transduction resulting in induction of apoptosis; regulation of transcription from RNA polymerase III promoter; positive regulation of protein ubiquitination; response to estrogen stimulus; androgen receptor signaling pathway; positive regulation of histone acetylation; positive regulation of transcription from RNA polymerase II promoter; response to ionizing radiation; G2/M transition DNA damage checkpoint; negative regulation of transcription, DNA-dependent; response to DNA damage stimulus

Disease: Breast-ovarian Cancer, Familial, Susceptibility To, 1; Pancreatic Cancer, Susceptibility To, 4; Breast Cancer