Petronczki Mark, Matos Joao, Mori Saori, Gregan Juraj, Bogdanova Aliona, Schwickart Martin, Mechtler Karl, Shirahige Katsuhiko, Zachariae Wolfgang, Nasmyth Kim
Research Institute of Molecular Pathology, Dr. Bohrgasse 7, A-1030 Vienna, Austria.
Cell. 2006 Sep 22;126(6):1049-64. doi: 10.1016/j.cell.2006.07.029.
In meiosis, a single round of DNA replication is followed by two consecutive rounds of chromosome segregation, called meiosis I and II. Disjunction of maternal from paternal centromeres during meiosis I depends on the attachment of sister kinetochores to microtubules emanating from the same pole. In budding yeast, monopolar attachment requires recruitment to kinetochores of the monopolin complex. How monopolin promotes monopolar attachment was unclear, as its subunits are poorly conserved and lack similarities to proteins with known functions. We show here that the monopolin subunit Mam1 binds tightly to Hrr25, a highly conserved casein kinase 1 delta/epsilon (CK1delta/epsilon), and recruits it to meiosis I centromeres. Hrr25 kinase activity and Mam1 binding are both essential for monopolar attachment. Since CK1delta/epsilon activity is important for accurate chromosome segregation during meiosis I also in fission yeast, phosphorylation of kinetochore proteins by CK1delta/epsilon might be an evolutionary conserved process required for monopolar attachment.
在减数分裂过程中，DNA复制一轮后紧接着是两轮连续的染色体分离，即减数分裂I和减数分裂II。减数分裂I期间母本和父本着丝粒的分离取决于姐妹动粒与来自同一极的微管的附着。在芽殖酵母中，单极附着需要将单极蛋白复合物募集到动粒上。单极蛋白如何促进单极附着尚不清楚，因为其亚基保守性较差，且与已知功能的蛋白质缺乏相似性。我们在此表明，单极蛋白亚基Mam1与Hrr25紧密结合，Hrr25是一种高度保守的酪蛋白激酶1δ/ε（CK1δ/ε），并将其募集到减数分裂I着丝粒上。Hrr25激酶活性和Mam1结合对于单极附着都是必不可少的。由于CK1δ/ε活性对于裂殖酵母减数分裂I期间准确的染色体分离也很重要，因此CK1δ/ε对动粒蛋白的磷酸化可能是单极附着所需的一个进化保守过程。
