Kawashima Shigehiro A, Tsukahara Tatsuya, Langegger Maria, Hauf Silke, Kitajima Tomoya S, Watanabe Yoshinori
Laboratory of Chromosome Dynamics, Institute of Molecular and Cellular Biosciences, University of Tokyo, Yayoi, Tokyo 113-0032, Japan.
Genes Dev. 2007 Feb 15;21(4):420-35. doi: 10.1101/gad.1497307.
Fission yeast shugoshin Sgo1 is meiosis specific and cooperates with protein phosphatase 2A to protect centromeric cohesin at meiosis I. The other shugoshin-like protein Sgo2, which requires the heterochromatin protein Swi6/HP1 for full viability, plays a crucial role for proper chromosome segregation at both mitosis and meiosis; however, the underlying mechanisms are totally elusive. We here demonstrate that, unlike Sgo1, Sgo2 is dispensable for centromeric protection of cohesin. Instead, Sgo2 interacts with Bir1/Survivin and promotes Aurora kinase complex localization to the pericentromeric region, to correct erroneous attachment of kinetochores and thereby enable tension-generating attachment. Forced localization of Bir1 to centromeres partly restored the defects of sgo2Delta. This newly identified interaction of shugoshin with Survivin is conserved between mitosis and meiosis and presumably across eukaryotes. We propose that ensuring bipolar attachment of kinetochores is the primary role of shugoshin and the role of cohesion protection might have codeveloped to facilitate this process.
裂殖酵母守护蛋白Sgo1是减数分裂特异性的,并且在减数分裂I中与蛋白磷酸酶2A协同作用以保护着丝粒黏连蛋白。另一种类守护蛋白Sgo2,其完全存活需要异染色质蛋白Swi6/HP1,在有丝分裂和减数分裂中对正确的染色体分离起着关键作用;然而,其潜在机制完全不清楚。我们在此证明,与Sgo1不同,Sgo2对于黏连蛋白的着丝粒保护是可有可无的。相反,Sgo2与Bir1/生存素相互作用,并促进极光激酶复合体定位于着丝粒周围区域,以纠正动粒的错误附着,从而实现产生张力的附着。将Bir1强制定位于着丝粒部分恢复了sgo2Δ的缺陷。这种新发现的守护蛋白与生存素之间的相互作用在有丝分裂和减数分裂之间是保守的,并且可能在真核生物中也是保守的。我们提出,确保动粒的双极附着是守护蛋白的主要作用,而黏连蛋白保护的作用可能是共同进化以促进这一过程。