Targeting the function of BRCA1 in the DNA damage response network.

乳腺癌1型易感性（BRCA1）蛋白是由同名肿瘤抑制基因BRCA1编码的蛋白。尽管BRCA1参与了细胞凋亡、细胞周期检查点激活、泛素化和转录调控等多个细胞过程，但本项目将主要关注BRCA1在DNA损伤反应（DDR）中的作用。BRCA1蛋白具有功能域BRCA1 c -末端域（BRCT）的串联重复序列。BRCA1的BRCT结构域特别令人感兴趣，因为该蛋白的结构排列形成了一个裂缝，使得在n端重复序列上有磷酸化丝氨酸的结合袋，在c端重复序列上有结合苯丙氨酸的疏水袋。与含有pSPxF基序的磷酸化蛋白伴侣结合的能力是BRCA1履行其在DNA修复和肿瘤抑制中的作用所必需的。为了研究这些蛋白-蛋白相互作用的机制并探索BRCA1在细胞环境中的功能，该项目将利用一系列Affimer蛋白作为野生型和突变型BRCA1的结合伙伴。可以阐明BRCA1的DDR机制的工作流程的开发可以应用于具有BRCT结构域的其他蛋白质，以便了解这些结构域在DDR，肿瘤抑制和癌症生物学中的更广泛的生物学意义。

Breast cancer type 1 susceptibility (BRCA1) protein is a protein encoded by the tumour suppressor gene of the same name, BRCA1. Although involved in several cellular processes such as apoptosis, activation of cell-cycle check points, ubiquitination and transcription regulation, this project will primarily focus on the role of BRCA1 in DNA damage response (DDR). The BRCA1 protein possesses a tandem repeat of the functional domain, BRCA1 C-terminus domain (BRCT). The BRCT domains of BRCA1 are of particular interest as the structural arrangement of the protein forms a cleft, enabling a binding pocket for phosphorylated serine on the N-terminal repeat and a hydrophobic pocket for binding phenylalanine on the C-terminal repeat. Capacity to bind with phosphorylated protein partners containing a pSPxF motif is necessary for BRCA1 to fulfil its role in DNA repair and tumour suppression. To investigate the mechanisms of these protein-protein interactions and probe the function of BRCA1 in the cellular environment, this project will utilise a collection of Affimer proteins as binding partners for wild type and mutant forms of BRCA1. The development of a workflow that can elucidate the DDR mechanisms of BRCA1 could be applied to other proteins with BRCT domains in order to understand the broader biological significance of these domains in DDR, tumour suppression and cancer biology overall.