De Piccoli Giacomo, Torres-Rosell Jordi, Aragón Luis
Cell Cycle Group, MRC Clinical Sciences Centre, Imperial College, Du Cane Road, London W12 0NN, UK.
Chromosome Res. 2009;17(2):251-63. doi: 10.1007/s10577-008-9016-8.
The structural maintenance of chromosome (SMC) proteins constitute the cores of three protein complexes involved in chromosome metabolism; cohesin, condensin and the Smc5-Smc6 complex. While the roles of cohesin and condensin in sister chromatid cohesion and chromosome condensation respectively have been described, the cellular function of Smc5-Smc6 is as yet not understood, consequently the less descriptive name. The complex is involved in a variety of DNA repair pathways. It contains activities reminiscent of those described for cohesin and condensin, as well as several DNA helicases and endonucleases. It is required for sister chromatid recombination, and smc5-smc6 mutants suffer from the accumulation of unscheduled recombination intermediates. The complex contains a SUMO-ligase and potentially an ubiquitin-ligase; thus Smc5-Smc6 might presently have a dull name, but it seems destined to be recognized as a key player in the maintenance of chromosome stability. In this review we summarize our present understanding of this enigmatic protein complex.
染色体结构维持（SMC）蛋白构成了参与染色体代谢的三种蛋白质复合物的核心，即黏连蛋白、凝聚蛋白和Smc5-Smc6复合物。虽然黏连蛋白和凝聚蛋白分别在姐妹染色单体黏连和染色体凝聚中的作用已被描述，但Smc5-Smc6的细胞功能尚未明确，因此其名称描述性较差。该复合物参与多种DNA修复途径。它具有一些与黏连蛋白和凝聚蛋白类似的活性，以及几种DNA解旋酶和核酸内切酶。它是姐妹染色单体重组所必需的，并且smc5-smc6突变体中会积累异常的重组中间体。该复合物含有一个SUMO连接酶，可能还含有一个泛素连接酶；因此，Smc5-Smc6目前可能名称平淡，但它似乎注定会被视为维持染色体稳定性的关键因子。在这篇综述中，我们总结了目前对这个神秘蛋白质复合物的理解。
