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The interaction of PP1 with BRCA1 and analysis of their expression in breast tumors

BACKGROUND: The breast cancer susceptibility gene, BRCA1, is implicated in multiple cellular processes including DNA repair, the transactivation of genes, and the ubiquitination of proteins; however its precise functions remain to be fully understood. Identification and characterization of BRCA1 pro...

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Autores principales: Winter, Sherry L, Bosnoyan-Collins, Lucine, Pinnaduwage, Dushanthi, Andrulis, Irene L
Formato: Texto
Lenguaje:English
Publicado: BioMed Central 2007
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1906825/
https://www.ncbi.nlm.nih.gov/pubmed/17511879
http://dx.doi.org/10.1186/1471-2407-7-85
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author Winter, Sherry L
Bosnoyan-Collins, Lucine
Pinnaduwage, Dushanthi
Andrulis, Irene L
author_facet Winter, Sherry L
Bosnoyan-Collins, Lucine
Pinnaduwage, Dushanthi
Andrulis, Irene L
author_sort Winter, Sherry L
collection PubMed
description BACKGROUND: The breast cancer susceptibility gene, BRCA1, is implicated in multiple cellular processes including DNA repair, the transactivation of genes, and the ubiquitination of proteins; however its precise functions remain to be fully understood. Identification and characterization of BRCA1 protein interactions may help to further elucidate the function and regulation of BRCA1. Additionally, detection of changes in the expression levels of BRCA1 and its interacting proteins in primary human breast tumors may further illuminate their role in the development of breast cancer. METHODS: We performed a yeast two-hybrid study to identify proteins that interact with exon11 of BRCA1 and identified Protein Phosphatase 1β (PP1β), an isoform of the serine threonine phosphatase, PP1. GST-pull down and co-immunoprecipitation assays were performed to further characterize this interaction. Additionally, Real-Time PCR was utilized to determine the expression of BRCA1, PP1α, β and γ in primary human breast tumors and normal breast tissue to identify alterations in the expression of these genes in breast cancer. RESULTS: PP1 and BRCA1 co-immunoprecipitate and the region within BRCA1 as well as the specific PP1 interacting domain mediating this interaction were identified. Following mRNA expression analysis, we identified low levels of BRCA1 and variable levels of PP1α and β in primary sporadic human breast tumors. Furthermore, BRCA1, PP1β and PP1γ were significantly higher in normal tissue specimens (BRCA1 p = 0.01, PP1β: p = 0.03, PP1γ, p = 1.9 × 10(-6)) compared to sporadic breast tumor samples. Interestingly, we also identified that ER negative tumors are associated with low levels of PP1α expression. CONCLUSION: The identification and characterization of the interaction of BRCA1 with PP1 and detection of changes in the expression of PP1 and genes encoding other BRCA1 associated proteins identifies important genetic pathways that may be significant to breast tumorigenesis. Alterations in the expression of genes, particularly phosphatases that operate in association with BRCA1, could negatively affect the function of BRCA1 or BRCA1 associated proteins, contributing to the development of breast cancer.
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spelling pubmed-19068252007-07-04 The interaction of PP1 with BRCA1 and analysis of their expression in breast tumors Winter, Sherry L Bosnoyan-Collins, Lucine Pinnaduwage, Dushanthi Andrulis, Irene L BMC Cancer Research Article BACKGROUND: The breast cancer susceptibility gene, BRCA1, is implicated in multiple cellular processes including DNA repair, the transactivation of genes, and the ubiquitination of proteins; however its precise functions remain to be fully understood. Identification and characterization of BRCA1 protein interactions may help to further elucidate the function and regulation of BRCA1. Additionally, detection of changes in the expression levels of BRCA1 and its interacting proteins in primary human breast tumors may further illuminate their role in the development of breast cancer. METHODS: We performed a yeast two-hybrid study to identify proteins that interact with exon11 of BRCA1 and identified Protein Phosphatase 1β (PP1β), an isoform of the serine threonine phosphatase, PP1. GST-pull down and co-immunoprecipitation assays were performed to further characterize this interaction. Additionally, Real-Time PCR was utilized to determine the expression of BRCA1, PP1α, β and γ in primary human breast tumors and normal breast tissue to identify alterations in the expression of these genes in breast cancer. RESULTS: PP1 and BRCA1 co-immunoprecipitate and the region within BRCA1 as well as the specific PP1 interacting domain mediating this interaction were identified. Following mRNA expression analysis, we identified low levels of BRCA1 and variable levels of PP1α and β in primary sporadic human breast tumors. Furthermore, BRCA1, PP1β and PP1γ were significantly higher in normal tissue specimens (BRCA1 p = 0.01, PP1β: p = 0.03, PP1γ, p = 1.9 × 10(-6)) compared to sporadic breast tumor samples. Interestingly, we also identified that ER negative tumors are associated with low levels of PP1α expression. CONCLUSION: The identification and characterization of the interaction of BRCA1 with PP1 and detection of changes in the expression of PP1 and genes encoding other BRCA1 associated proteins identifies important genetic pathways that may be significant to breast tumorigenesis. Alterations in the expression of genes, particularly phosphatases that operate in association with BRCA1, could negatively affect the function of BRCA1 or BRCA1 associated proteins, contributing to the development of breast cancer. BioMed Central 2007-05-19 /pmc/articles/PMC1906825/ /pubmed/17511879 http://dx.doi.org/10.1186/1471-2407-7-85 Text en Copyright © 2007 Winter et al; licensee BioMed Central Ltd. http://creativecommons.org/licenses/by/2.0 This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( (http://creativecommons.org/licenses/by/2.0) ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Research Article
Winter, Sherry L
Bosnoyan-Collins, Lucine
Pinnaduwage, Dushanthi
Andrulis, Irene L
The interaction of PP1 with BRCA1 and analysis of their expression in breast tumors
title The interaction of PP1 with BRCA1 and analysis of their expression in breast tumors
title_full The interaction of PP1 with BRCA1 and analysis of their expression in breast tumors
title_fullStr The interaction of PP1 with BRCA1 and analysis of their expression in breast tumors
title_full_unstemmed The interaction of PP1 with BRCA1 and analysis of their expression in breast tumors
title_short The interaction of PP1 with BRCA1 and analysis of their expression in breast tumors
title_sort interaction of pp1 with brca1 and analysis of their expression in breast tumors
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1906825/
https://www.ncbi.nlm.nih.gov/pubmed/17511879
http://dx.doi.org/10.1186/1471-2407-7-85
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