Acetylation of SMC3 subunit of chromosomal arm associated cohesin by ESCO1 or ESCO2

Acetyltransferases ESCO1 and ESCO2 are homologs of the S. cerevisiae acetyltransferase Eco1, essential for viability in yeast. ESCO1 and ESCO2 share sequence homology in the C-terminal region, consisting of a H2C2 zinc finger motif and an acetyltransferase domain (Hou and Zou 2005). Both ESCO1 and ESCO2 acetylate the cohesin subunit SMC3 on two lysine residues, K105 and K106 (Zhang et al. 2008), an important step in the establishment of sister-chromatid cohesion during the S-phase of the cell cycle. These dual acetylations on SMC3 are deacetylated by HDAC8 after the cohesin removal from chromatin for the dissociation and recycling of cohesin subunits (Deardorff et al. 2012). ESCO1 and ESCO2 differ in their N-termini, which are necessary for chromatin binding, and may perform distinct functions in sister chromatid cohesion (Hou and Zou 2005), as suggested by the study of Esco2 knockout mice (Whelan et al. 2012).

乙酰转移酶ESCO1和ESCO2是酿酒酵母乙酰转移酶Eco1的同源物，对于酵母的存活至关重要。ESCO1和ESCO2在C端区域具有序列同源性，包括一个H2C2锌指基序和一个乙酰转移酶结构域（Hou和Zou 2005）。两者均在SMC3凝聚子单元的两个赖氨酸残基K105和K106上进行乙酰化（Zhang等人，2008年），这是细胞周期S期建立姐妹染色单体连接的重要步骤。这些对SMC3的双重乙酰化在凝聚子从染色质中移除并由HDAC8去乙酰化后，对于凝聚子亚基的解聚和循环利用至关重要（Deardorff等人，2012年）。ESCO1和ESCO2在其N端区域存在差异，这些区域对于染色质结合是必要的，并且可能在姐妹染色单体连接中执行不同的功能（Hou和Zou 2005），正如Esco2敲除小鼠的研究所暗示的（Whelan等人，2012年）。