Spatial separation of phosphatase and kinase activity within the Bub complex is required for proper mitosis  

作　　者：Lei Wang Thomas Kruse Blanca López-Méndez Yuqing Zhang Chunlin Song Lei Zhu Bing Li Jing Fang Zhimin Lu Jakob Nilsson Gang Zhang 

机构地区：[1]The Cancer Institute,The Affiliated Hospital of Qingdao University,Qingdao University,Qingdao 266061,China [2]Novo Nordisk Foundation Center for Protein Research,Faculty of Health and Medical Sciences,University of Copenhagen,Copenhagen DK-2200,Denmark [3]The Department of Genetics and Cell Biology,Basic Medical College,Qingdao University,Qingdao 266061,China [4]Institute of Translational Medicine,Zhejiang University School of Medicine,Hangzhou 310029,China

出　　处：《Journal of Molecular Cell Biology》2022年第11期24-35,共12页分子细胞生物学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(31970666);Taishan Scholar Project(tsqn201812054)from Shandong,China;Work at the Novo Nordisk Foundation Center for Protein Research was supported by the grant NNF14CC0001;J.N.is supported by grants from the Danish Cancer Society(R269-A15586-B17);Independent Research Fund Denmark(8021-00101B and 0134-00199B);Novo Nordisk Foundation(NNF20OC0065098).

摘　　要：The Bub1 and BubR1 kinetochore proteins support proper chromosome segregation and mitotic checkpoint activity. Bub1 and BubR1 are paralogs with Bub1 being a kinase, while BubR1 localizes the PP2A-B56 protein phosphatase to kinetochores in humans. Whether this spatial separation of kinase and phosphatase activity is important is unclear as some organisms integrate both activities into one Bub protein. Here, we engineer human Bub1 and BubR1 proteins integrating kinase and phosphatase activities into one protein and show that these do not support normal mitotic progression. A Bub1–PP2A-B56 complex can support chromosome alignment but results in impairment of the checkpoint due to dephosphorylation of the Mad1 binding site in Bub1. Furthermore, a chimeric BubR1 protein containing the Bub1 kinase domain induces delocalized H2ApT120 phosphorylation, resulting in the reduction of centromeric hSgo2 and chromosome segregation errors. Collectively, these results argue that the spatial separation of kinase and phosphatase activities within the Bub complex is required for balancing its functions in the checkpoint and chromosome alignment.

关 键 词：MITOSIS spindle assembly checkpoint KINETOCHORES BUB1 BUBR1 PP2A/B56 

分 类 号：Q34[生物学—遗传学]