Hohl Marcel, Kochańczyk Tomasz, Tous Cristina, Aguilera Andrés, Krężel Artur, Petrini John H J
Molecular Biology Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA.
Laboratory of Chemical Biology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland.
Mol Cell. 2015 Feb 5;57(3):479-91. doi: 10.1016/j.molcel.2014.12.018. Epub 2015 Jan 15.
Rad50 contains a conserved Zn(2+) coordination domain (the Rad50 hook) that functions as a homodimerization interface. Hook ablation phenocopies Rad50 deficiency in all respects. Here, we focused on rad50 mutations flanking the Zn(2+)-coordinating hook cysteines. These mutants impaired hook-mediated dimerization, but recombination between sister chromatids was largely unaffected. This may reflect that cohesin-mediated sister chromatid interactions are sufficient for double-strand break repair. However, Mre11 complex functions specified by the globular domain, including Tel1 (ATM) activation, nonhomologous end joining, and DNA double-strand break end resection were affected, suggesting that dimerization exerts a broad influence on Mre11 complex function. These phenotypes were suppressed by mutations within the coiled-coil and globular ATPase domains, suggesting a model in which conformational changes in the hook and globular domains are transmitted via the extended coils of Rad50. We propose that transmission of spatial information in this manner underlies the regulation of Mre11 complex functions.
Rad50包含一个保守的锌离子配位结构域（Rad50钩），该结构域作为同二聚化界面发挥作用。钩的缺失在各方面都模拟了Rad50缺陷的表型。在这里，我们聚焦于锌离子配位钩半胱氨酸两侧的rad50突变。这些突变体损害了钩介导的二聚化，但姐妹染色单体之间的重组基本未受影响。这可能反映出黏连蛋白介导的姐妹染色单体相互作用足以进行双链断裂修复。然而，由球状结构域指定的Mre11复合物功能，包括Tel1（ATM）激活、非同源末端连接和DNA双链断裂末端切除均受到影响，这表明二聚化对Mre11复合物功能具有广泛影响。这些表型被卷曲螺旋和球状ATP酶结构域内的突变所抑制，这提示了一种模型，即钩和球状结构域的构象变化通过Rad50的延伸螺旋进行传递。我们提出，以这种方式传递空间信息是Mre11复合物功能调控的基础。
