2001;10:353C360

2001;10:353C360. recombinant ValBRCA1 was less stable than wtBRCA1 and, unlike the latter, failed to associate with BRIP1, CtIP, and Rap80, and to re-localize to sites of DNA damage. Yeast two-hybrid analysis revealed a compromised interaction with FHL2 and with KPNA2, which is likely responsible for improper subcellular localization of ValBRCA1. In addition, we found four new breast/ovarian cancer families of Italian ancestry who carried this sequence alteration. These results provide the first evidence of the effect of BRCA1 p. V1688del on protein stability and function, supporting the view that it is a deleterious mutation. Mutant IDH1-IN-2 Multimodal analyses like ours could advance understanding of tumor suppression by BRCA1, and ultimately contribute to developing efficient strategies for screening and characterization of VUSs. and genes is important in clinical practice and has become a valuable tool for breast/ovarian cancer risk estimation and reduction. To appraise the cancer proclivity of each detected sequence alteration can be challenging, leaving risk communication and management uncertain. The full-length gene product, a 220 kDa nuclear phosphoprotein, functions in multiple cellular processes, including homologous recombination (HR)-mediated DNA damage repair, cell cycle checkpoint control, transcriptional regulation, centrosome duplication, heterochromatin maintenance, and mitosis (2, 3). The BRCA1 protein has a long, intrinsically disordered central region (4) bracketed by two evolutionarily conserved domains: an amino (N)-terminal RING finger domain and two tandem carboxyl (C)-terminal BRCA1 C-terminus (BRCT) repeats (BRCT domain). The RING finger exhibits E3 ubiquitin ligase activity upon heterodimerization with the structurally-related partner protein, BRCA1-associated RING domain (BARD1) (5). The BRCTs are highly structured ~95 amino acid (aa) motifs, found in more than 50 proteins involved in DNA repair and cell cycle checkpoint regulation (6). They are characterized by a distinct cluster of hydrophobic amino acids, which constitute the core of the repeat fold (6), and contribute to the stability of BRCA1 (7). The two BRCT repeats behave as a single functional unit, which specifically Mutant IDH1-IN-2 binds phospho-serine (pSer)- or phospho-threonine (pThr)-containing proteins (8, 9). Interactions with several such proteins, BRIP1 (BRCA1 interacting protein 1), also known as BACH1 (BRCA1-associated C-terminal helicase 1) (10), and CtIP (C-terminal binding protein (CtBP)-interacting protein) (11) have been elucidated in detail, providing insights into ligand recognition (12C14). Most functionally detrimental mutations identified thus far are frame-shift and nonsense Mutant IDH1-IN-2 sequence changes that result in premature translational termination (15). Genomic rearrangements, missense mutations and splice site mutations account for the remainder of the mutational spectrum (15). An increasing number of variants of uncertain significance (VUSs) are being identified and catalogued in the Breast Rabbit Polyclonal to GPR116 Cancer Information Core (BIC) database1. Their biological and clinical relevance still awaits elucidation, with consequent delays in decision-making. Up to 20% (this percentage being higher in non-white populations (16)) of all sequence changes are currently categorized as VUSs (17). Several reported methods aim to determine whether or not a VUS is cancer-predisposing. A recently developed (18), and subsequently expanded (17) or adapted (19, 20), multifactorial-likelihood model, which integrates data from several sources, seems to represent the most comprehensive strategy to reliably state for or against causality. Studies providing functional support to the modeled predictions are always an invaluable and sought-after Mutant IDH1-IN-2 adjunct. functional assays are currently available only for sequence changes residing in the structurally and Mutant IDH1-IN-2 functionally well-characterized RING and BRCT domains. The application of a multifactorial likelihood-based approach has recently suggested BRCA1 p.V1688del (c.5181_5183delGTT), a sequence variant recurrent amongst Italian families, as a likely pathogenic alteration (21). No studies have yet been carried out to ascertain whether and how this single-amino acid in-frame deletion in the BRCA1 C-terminus impacts the biological function of the mutant protein. Here, we employed a multidimensional approach to investigate the functional repercussions of BRCA1 p.V1688del. Our results show that this sequence alteration profoundly destabilizes.

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