Phosphorylation of Astrin Regulates Its Kinetochore Function.
The error-free segregation of chromosomes, which requires the precisely timed search and capture of chromosomes by spindles during early mitotic and meiotic cell division, is responsible for genomic stability and is achieved by the spindle assembly checkpoint in the metaphase-anaphase transition. Mitotic kinases orchestrate M phase events, such as the reorganization of cell architecture and kinetochore (KT) composition with the exquisite phosphorylation of mitotic regulators, to ensure timely and temporal progression. However, the molecular mechanisms underlying the changes of KT composition for stable spindle attachment during mitosis are poorly understood. Here, we show that the sequential action of the kinase Cdk1 and the phosphatase Cdc14A control spindle attachment to KTs. During prophase, the mitotic spindle protein Spag5/Astrin is transported into centrosomes by Kinastrin and phosphorylated at Ser-135 and Ser-249 by Cdk1, which, in prometaphase, is loaded onto the spindle and targeted to KTs. We also demonstrate that Cdc14A dephosphorylates Astrin, and therefore the overexpression of Cdc14A sequesters Astrin in the centrosome and results in aberrant chromosome alignment. Mechanistically, Plk1 acts as an upstream kinase for Astrin phosphorylation by Cdk1 and targeting phospho-Astrin to KTs, leading to the recruitment of outer KT components, such as Cenp-E, and the stable attachment of spindles to KTs. These comprehensive findings reveal a regulatory circuit for protein targeting to KTs that controls the KT composition change of stable spindle attachment and chromosome integrity.
Department of Biological Sciences, Sungkyunkwan University, Suwon 440-746, Republic of Korea and.
Hee Jin
HJ
Chung
Research Center for Cell Fate Control, College of Pharmacy, Sookmyung Women's University, Seoul 04310, Republic of Korea.
Ji Eun
JE
Park
Department of Biological Sciences, Sungkyunkwan University, Suwon 440-746, Republic of Korea and.
Nam Soo
NS
Lee
Department of Biological Sciences, Sungkyunkwan University, Suwon 440-746, Republic of Korea and From the Center for Neuroscience Imaging Research, Institute for Basic Science and khtcat@skku.edu.
Hongtae
H
Kim
Research Center for Cell Fate Control, College of Pharmacy, Sookmyung Women's University, Seoul 04310, Republic of Korea cyjang@sookmyung.ac.kr.
Chang-Young
CY
Jang
D000705:Anaphase / Q000502:physiology*; D016203:CDC2 Protein Kinase; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism; D018844:Cyclin-Dependent Kinases / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D018386:Kinetochores / Q000378:metabolism*; D008677:Metaphase / Q000502:physiology*; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation / Q000502:physiology; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D017027:Protein Tyrosine Phosphatases; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D000097869:Polo-Like Kinase 1
D016203:CDC2 Protein Kinase; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D018844:Cyclin-Dependent Kinases; D010744:Phosphoric Monoester Hydrolases; D017346:Protein Serine-Threonine Kinases; D017027:Protein Tyrosine Phosphatases; D011518:Proto-Oncogene Proteins; D000097869:Polo-Like Kinase 1; C486663:SPAG5 protein, human; C068688:centromere protein E; C528899:CDK1 protein, human; C120902:CDC14A protein, human
cell cycle; cell division; cyclin-dependent kinase (Cdk); kinetochore; mitosis; phosphorylation