Losada Ana, Hirano Tatsuya
Spanish National Cancer Center (CNIO), Madrid.
Genes Dev. 2005 Jun 1;19(11):1269-87. doi: 10.1101/gad.1320505.
Structural maintenance of chromosomes (SMC) proteins are chromosomal ATPases, highly conserved from bacteria to humans, that play fundamental roles in many aspects of higher-order chromosome organization and dynamics. In eukaryotes, SMC1 and SMC3 act as the core of the cohesin complexes that mediate sister chromatid cohesion, whereas SMC2 and SMC4 function as the core of the condensin complexes that are essential for chromosome assembly and segregation. Another complex containing SMC5 and SMC6 is implicated in DNA repair and checkpoint responses. The SMC complexes form unique ring- or V-shaped structures with long coiled-coil arms, and function as ATP-modulated, dynamic molecular linkers of the genome. Recent studies shed new light on the mechanistic action of these SMC machines and also expanded the repertoire of their diverse cellular functions. Dissecting this class of chromosomal ATPases is likely to be central to our understanding of the structural basis of genome organization, stability, and evolution.
染色体结构维持（SMC）蛋白是一类染色体ATP酶，从细菌到人类高度保守，在高阶染色体组织和动态变化的许多方面发挥着重要作用。在真核生物中，SMC1和SMC3作为黏连蛋白复合体的核心，介导姐妹染色单体黏连；而SMC2和SMC4则作为凝缩蛋白复合体的核心，对染色体组装和分离至关重要。另一个包含SMC5和SMC6的复合体参与DNA修复和检查点反应。SMC复合体形成具有长卷曲螺旋臂的独特环状或V形结构，并作为由ATP调节的基因组动态分子连接体发挥作用。最近的研究为这些SMC机器的作用机制提供了新的线索，也扩展了它们多样的细胞功能。剖析这类染色体ATP酶可能是我们理解基因组组织、稳定性和进化的结构基础的核心。
