title: BRCA1 is a 220-kDa nuclear phosphoprotein that is expressed and phosphorylated in a cell cycle-dependent manner.
abstract: Mouse polyclonal antibodies, raised against three regions of the human BRCA1 protein, were characterized and revealed BRCA1 as a 220-kDa nuclear phosphoprotein in normal cells. All three antisera recognize both in vitro-translated and recombinant, baculovirus-derived BRCA1, which co-migrate with BRCA1 from the human breast epithelia cell line, HBL100. BRCA1 expression and phosphorylation are shown to be cell cycle dependent, with greatest expression and phosphorylation occurring in S and M phases. Cyclin-dependent kinase 2 and other kinases associated with cyclins D and A are shown to bind to and phosphorylate BRCA1, suggesting that the biological activity of BRCA1 may be regulated by cyclin-dependent kinases.
authors.affiliation: Center for Molecular Medicine/Institute of Biotechnology, The University of Texas Health Science Center at San Antonio, San Antonio, Texas 78245, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.forename: A A
authors.initials: AA
authors.lastname: Farmer
authors.forename: C F
authors.initials: CF
authors.lastname: Chen
authors.forename: D C
authors.initials: DC
authors.lastname: Jones
authors.forename: P L
authors.initials: PL
authors.lastname: Chen
authors.forename: W H
authors.initials: WH
authors.lastname: Lee
mesh_terms: D019313:BRCA1 Protein; D002451:Cell Compartmentation; D002453:Cell Cycle; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D006801:Humans; D009363:Neoplasm Proteins / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011994:Recombinant Proteins; D014157:Transcription Factors / Q000378:metabolism*
chemical_list: D019313:BRCA1 Protein; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011994:Recombinant Proteins; D014157:Transcription Factors; D018844:Cyclin-Dependent Kinases