PALB2 functionally connects the breast cancer susceptibility proteins BRCA1 and BRCA2.
PALB2 functionally connects the breast cancer susceptibility proteins BRCA1 and BRCA2.
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DOI：
10.1158/1541-7786.mcr-09-0123
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发表时间：
2009-07
期刊：
影响因子：
--
通讯作者：
Andreassen PR
中科院分区：
文献类型：
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作者：
Zhang F;Fan Q;Ren K;Andreassen PR
BRCA 1和BRCA 2与遗传性乳腺癌和卵巢癌显著相关。编码的蛋白质在DNA损伤反应中起作用，但BRCA 1和BRCA 2之间没有功能联系。我们在这里展示了PALB 2在物理上和功能上将BRCA 1和BRCA 2连接到一个DNA损伤反应网络中，该网络还包括RAD 51重组酶。PALB 2直接结合BRCA 1，如用每种蛋白质的细菌表达片段所确定的。此外，PALB 2分别通过其NH 2和COOH末端独立地与BRCA 1和BRCA 2相互作用。重要的是，PALB 2卷曲螺旋结构域的两个点突变体（L21 P和L24 P）或NH 2末端缺失（Δ1-70）破坏了其与BRCA 1的相互作用。我们已经用PALB 2 Δ1-70、PALB 2-L21 P或PALB 2-L24 P或用缺乏与BRCA 2相互作用的COOH末端截短的PALB 2重建了PALB 2缺陷细胞。使用这些细胞的提取物，我们发现PALB 2介导BRCA 2与BRCA 1的COOH末端片段的物理相互作用。通过BRCA 1、PALB 2、BRCA 2和RAD 51分析这些细胞中的病灶组装表明，BRCA 1招募PALB 2，PALB 2反过来组织BRCA 2和RAD 51。对丝裂霉素C的抗性和通过同源重组修复DNA双链断裂需要PALB 2与BRCA 1和BRCA 2两者的相互作用。这些结果表明，BRCA 1和BRCA 2合作的DNA损伤反应中的PALB 2依赖的方式，并有重要的意义，乳腺癌/卵巢癌的发生和化疗与DNA链间交联剂。
BRCA1 and BRCA2 are prominently associated with inherited breast and ovarian cancer. The encoded proteins function in DNA damage responses, but no functional link between BRCA1 and BRCA2 has been established. We show here that PALB2 physically and functionally connects BRCA1 and BRCA2 into a DNA damage response network that also includes the RAD51 recombinase. PALB2 directly binds BRCA1, as determined with bacterially expressed fragments of each protein. Furthermore, PALB2 independently interacts with BRCA1 and BRCA2 through its NH2 and COOH termini, respectively. Critically, two point mutants (L21P and L24P) of the PALB2 coiled-coil domain or an NH2-terminal deletion (Δ1–70) disrupt its interaction with BRCA1. We have reconstituted PALB2-deficient cells with PALB2Δ1–70, PALB2-L21P, or PALB2-L24P, or with COOH-terminally truncated PALB2 that is deficient for interaction with BRCA2. Using extracts from these cells, we find that PALB2 mediates the physical interaction of BRCA2 with a COOH-terminal fragment of BRCA1. Analysis of the assembly of foci in these cells by BRCA1, PALB2, BRCA2, and RAD51 suggests that BRCA1 recruits PALB2, which in turn organizes BRCA2 and RAD51. Resistance to mitomycin C and the repair of DNA double-strand breaks by homologous recombination require the interaction of PALB2 with both BRCA1 and BRCA2. These results suggest that BRCA1 and BRCA2 cooperate in DNA damage responses in a PALB2-dependent manner, and have important implications for the genesis of breast/ovarian cancer and for chemotherapy with DNA interstrand cross-linking agents.