BRCA1-Associated Protein 1 Interferes with BRCA1/BARD1 RING Heterodimer Activity
BRCA1-Associated Protein 1 Interferes with BRCA1/BARD1 RING Heterodimer Activity
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DOI：
10.1158/0008-5472.can-08-3355
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发表时间：
2009-01-01
期刊：
影响因子：
11.2
通讯作者：
Ohta, Tomohiko
中科院分区：
文献类型：
--
作者：
Nishikawa, Hiroyuki;Wu, Wenwen;Ohta, Tomohiko
乳腺和卵巢肿瘤抑制基因BRCA1与BARD1构成环状异二聚体E3连接酶。BRCA1相关蛋白1(BAP1)是一种泛素COOH末端水解酶，最初被鉴定为与BRCA1的King Finger结构域结合的蛋白质。然而，BAPI对BRCA1/BARD1的E3活性的贡献尚不清楚。在这里，我们报告了BAPI与BARD1相互作用，从而抑制BRCA1/BARD1的E3连接酶活性。由BAPI的182-365残基组成的结构域与BARD1的环指结构域相互作用，表面等离子体共振光谱(BIA-CORE)分析表明BAP1干扰BRCA1/BARD1的结合。这种干扰导致BRCA1/BARD1抑制BRCA1的自动泛素化和NPM1/B23的泛素化。尽管BAP1在体外能够去泛素化BRCA1/BARD1介导的多泛素链，但BAP1的催化失活突变体C91S在体内外仍能抑制这种泛素化，这意味着第二种作用机制。重要的是，短发夹状RNA抑制BAPI的表达导致细胞对电离辐射的超敏反应，并延缓S期的进展。综上所述，这些结果表明BAP1和BRCA1/BARD1在DNA损伤反应和细胞周期中协调调节泛素化。[癌症资源2009；69(1)：111-9]
The breast and ovarian tumor suppressor BRCA1 constitutes a RING heterodimer E3 ligase with BARD1. BRCA1-associated protein 1 (BAP1) is a ubiquitin COOH-terminal hydrolase that was initially identified as a protein that bound to the KING finger domain of BRCA1. However, how BAPI contributes to the E3 activity of BRCA1/BARD1 is unclear. Here, we report that BAPI interacts with BARD1 to inhibit the E3 ligase activity of BRCA1/BARD1. Domains comprised by residues 182-365 of BAPI interact with the RING finger domain of BARD1, and surface plasmon resonance spectroscopy (BIA-core) analyses showed that BAP1 interferes with the BRCA1/BARD1 association. The perturbation resulted in inhibition of BRCA1 autoubiquitination and NPM1/B23 ubiquitination by BRCA1/BARD1. Although BAP1 was capable of deubiquitinating the polyubiquitin chains mediated by BRCA1/BARD1 in vitro, a catalytically inactive mutant of BAP1, C91S, still inhibited the tibiquitination in vitro and in vivo, implicating a second mechanism of action. Importantly, inhibition of BAPI expression by short hairpin RNA resulted in hypersensitivity of the cells to ionizing irradiation and in retardation of S-phase progression. Together, these results suggest that BAP1 and BRCA1/BARD1 coordinately regulate ubiquitination during the DNA damage response and the cell cycle. [Cancer Res 2009;69(1):111-9]