The helicase FBH1 is tightly regulated by PCNA via CRL4(Cdt2)-mediated proteolysis in human cells
The helicase FBH1 is tightly regulated by PCNA via CRL4(Cdt2)-mediated proteolysis in human cells
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DOI：
10.1093/nar/gkt397
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发表时间：
2013-07-01
影响因子：
14.9
通讯作者：
Kannouche, Patricia L.
中科院分区：
文献类型：
--
作者：
Bacquin, Agathe;Pouvelle, Caroline;Kannouche, Patricia L.
在复制过程中，DNA损伤会对复制分叉进程和细胞活力构成挑战。同源重组(HR)和跨损伤合成(TLS)通路似乎是DNA复制恢复和完成的主要参与者。人类细胞如何协调这两条途径以维持基因组的稳定尚不清楚。许多解旋酶参与了HR的调节。其中，解旋酶FBH1聚集在DNA损伤部位，并通过其抗重组酶活性潜在地抑制HR。然而，对其在体内的调控知之甚少。在这里，我们报告了一种控制DNA损伤后FBH1降解的机制。首先，我们发现，滑动钳制增殖细胞核抗原对于FBH1在复制工厂或DNA损伤部位的募集是至关重要的。结果表明，FBH1的抗重组酶活性部分依赖于其与增殖细胞核抗原的相互作用。有趣的是，FBH1在其重新定位后，通过增殖细胞核抗原相互作用肽(PIP)降解，被库林环连合酶4-CDT2(CRL4(CDT2))-增殖细胞核抗原途径降解。重要的是，不可降解的FBH1突变体的表达损害了紫外线照射细胞中TLS聚合酶ETA向染色质的募集。因此，我们认为在DNA损伤后，可能需要FBH1限制HR，然后通过CDT2-蛋白酶体途径降解，以促进TLS途径。
During replication, DNA damage can challenge replication fork progression and cell viability. Homologous Recombination (HR) and Translesion Synthesis (TLS) pathways appear as major players involved in the resumption and completion of DNA replication. How both pathways are coordinated in human cells to maintain genome stability is unclear. Numerous helicases are involved in HR regulation. Among them, the helicase FBH1 accumulates at sites of DNA damage and potentially constrains HR via its anti-recombinase activity. However, little is known about its regulation in vivo. Here, we report a mechanism that controls the degradation of FBH1 after DNA damage. Firstly, we found that the sliding clamp Proliferating Cell Nuclear Antigen (PCNA) is critical for FBH1 recruitment to replication factories or DNA damage sites. We then showed the anti-recombinase activity of FBH1 is partially dependent on its interaction with PCNA. Intriguingly, after its re-localization, FBH1 is targeted for degradation by the Cullin-ring ligase 4-Cdt2 (CRL4(Cdt2))-PCNA pathway via a PCNA-interacting peptide (PIP) degron. Importantly, expression of non-degradable FBH1 mutant impairs the recruitment of the TLS polymerase eta to chromatin in UV-irradiated cells. Thus, we propose that after DNA damage, FBH1 might be required to restrict HR and then degraded by the Cdt2-proteasome pathway to facilitate TLS pathway.