Multimodal Assessment of Protein Functional Deficiency Supports Pathogenicity of BRCA1 p.V1688del
Multimodal Assessment of Protein Functional Deficiency Supports Pathogenicity of BRCA1 p.V1688del
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DOI：
10.1158/0008-5472.can-09-1440
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发表时间：
2009-09-01
期刊：
影响因子：
11.2
通讯作者：
Garber, Judy E.
中科院分区：
文献类型：
--
作者：
De Nicolo, Arcangela;Parisini, Emilio;Garber, Judy E.
明确区分中性变异和有害突变对于为 BRCA1 或 BRCA2 序列改变的个体提供适当的咨询至关重要。越来越多的意义不确定的变异（VUS）正在被识别，其未分类的生物学效应引起了临床关注。最近，一种基于可能性的多因素方法提示了 BRCA1 p.V1688del 的疾病因果关系，这是意大利乳腺癌/卵巢癌家族中复发的 VUS。 BRCA1 COOH 末端 (BRCT) 结构域中的单个氨基酸缺失是否以及如何影响突变蛋白 (Delta ValBRCA1) 的功能尚未阐明。我们对 AValBRCA1 进行了全面的功能表征，包括比较结构建模、蛋白质稳定性和关联分析以及 DNA 修复功能分析。我们的模型预测了 BRCA1 p.V1688del 引起的 BRCT 结构域不稳定和折叠破坏。一致地，重组 Delta ValBRCA1 不如野生型 BRCA1 稳定，并且与野生型 BRCA1 不同，重组 Delta ValBRCA1 无法与 BRIP1、CtIP 和 Rap80 结合，也无法重新定位到 DNA 损伤位点。酵母双杂交分析揭示了与 FHL2 和 KPNA2 的相互作用受损，这可能是 Delta ValBRCA1 亚细胞定位不当的原因。此外，我们还发现了四个新的意大利血统乳腺癌/卵巢癌家族，他们携带这种序列改变。这些结果提供了 BRCA1 p.V1688del 对蛋白质稳定性和功能影响的第一个证据，支持了它是一种有害突变的观点。像我们这样的多模式分析可以促进对 BRCA1 肿瘤抑制的理解，并最终有助于制定有效的 VUS 筛查和表征策略。 [癌症研究 2009;69(17):7030-7]
Unequivocal discrimination between neutral variants and deleterious mutations is crucial for appropriate counseling of individuals with a BRCA1 or BRCA2 sequence change. An increasing number of variants of uncertain significance (VUS) are being identified, the unclassified biological effect of which poses clinical concerns. A multifactorial likelihood-based approach recently suggested disease causality for BRCA1 p.V1688del, a VUS recurrent in Italian breast/ovarian cancer families. Whether and how this single amino acid deletion in the BRCA1 COOH terminus (BRCT) domain affects the function of the mutant protein (Delta ValBRCA1) has not been elucidated. We undertook comprehensive functional characterization of AValBRCA1, comprising comparative structural modeling, analysis of protein stability and associations, and analysis of DNA repair function. Our model predicted BRCT domain destabilization and folding disruption caused by BRCA1 p.V1688del. Consistently, the recombinant Delta ValBRCA1 was less stable than wild-type BRCA1 and, unlike the latter, failed to associate with BRIP1, CtIP, and Rap80 and to relocalize to sites of DNA damage. Yeast two-hybrid analysis revealed a compromised interaction with FHL2 and KPNA2, which is likely responsible for improper subcellular localization of Delta 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. Multimodal analyses like ours could advance understanding of tumor suppression by BRCA1 and ultimately contribute to developing efficient strategies for screening and characterization of VUS. [Cancer Res 2009;69(17):7030-7]