Murphy Lynea A, Sarge Kevin D
Department of Toxicology, Chandler Medical Center, University of Kentucky, Lexington, KY 40536, USA.
Biochem Biophys Res Commun. 2008 Dec 19;377(3):1007-11. doi: 10.1016/j.bbrc.2008.10.114. Epub 2008 Oct 31.
Condensin is a 5 subunit complex that plays an important role in the structure of chromosomes during mitosis. It is known that phosphorylation of condensin subunits by cdc2/cyclin B at the beginning of mitosis is important for condensin activity, but the sites of these phosphorylation events have not been identified nor has their role in regulating condensin function. Here we identify two threonine residues in the CAP-G subunit of condensin, threonines 308 and 332, that are targets of cdc2/cyclin B phosphorylation. Mutation of these threonines to alanines results in defects in CAP-G localization with chromosomes during mitosis. These results are the first to identify phosphorylation sites within the condensin complex that regulate condensin localization with chromosomal DNA.
凝聚素是一种由5个亚基组成的复合体，在有丝分裂过程中对染色体结构起着重要作用。已知在有丝分裂开始时，cdc2/细胞周期蛋白B对凝聚素亚基的磷酸化对于凝聚素活性很重要，但这些磷酸化事件的位点尚未确定，其在调节凝聚素功能中的作用也不清楚。在这里，我们在凝聚素的CAP-G亚基中鉴定出两个苏氨酸残基，即苏氨酸308和332，它们是cdc2/细胞周期蛋白B磷酸化的靶点。将这些苏氨酸突变为丙氨酸会导致有丝分裂期间CAP-G与染色体的定位出现缺陷。这些结果首次确定了凝聚素复合物中调节凝聚素与染色体DNA定位的磷酸化位点。
