A microtubule-associated zinc finger protein, BuGZ, regulates mitotic chromosome alignment by ensuring Bub3 stability and kinetochore targeting.
Equal chromosome segregation requires proper assembly of many proteins, including Bub3, onto kinetochores to promote kinetochore-microtubule interactions. By screening for mitotic regulators in the spindle envelope and matrix (Spemix), we identify a conserved Bub3 interacting and GLE-2-binding sequence (GLEBS) containing ZNF207 (BuGZ) that associates with spindle microtubules and regulates chromosome alignment. Using its conserved GLEBS, BuGZ directly binds and stabilizes Bub3. BuGZ also uses its microtubule-binding domain to enhance the loading of Bub3 to kinetochores that have assumed initial interactions with microtubules in prometaphase. This enhanced Bub3 loading is required for proper chromosome alignment and metaphase to anaphase progression. Interestingly, we show that microtubules are required for the highest kinetochore loading of Bub3, BubR1, and CENP-E during prometaphase. These findings suggest that BuGZ not only serves as a molecular chaperone for Bub3 but also enhances its loading onto kinetochores during prometaphase in a microtubule-dependent manner to promote chromosome alignment.
State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; Department of Embryology, Carnegie Institution for Science, 3520 San Martin Dr., Baltimore, MD 21218, USA.
Hao
H
Jiang
State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
Xiaonan
X
He
Department of Embryology, Carnegie Institution for Science, 3520 San Martin Dr., Baltimore, MD 21218, USA.
Shusheng
S
Wang
Department of Embryology, Carnegie Institution for Science, 3520 San Martin Dr., Baltimore, MD 21218, USA.
Junling
J
Jia
State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China; Department of Embryology, Carnegie Institution for Science, 3520 San Martin Dr., Baltimore, MD 21218, USA.
Yihan
Y
Wan
Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA.
Yueju
Y
Wang
State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China.
Rong
R
Zeng
Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037, USA.
John
J
Yates
State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China. Electronic address: xlzhu@sibcb.ac.cn.
Xueliang
X
Zhu
Department of Embryology, Carnegie Institution for Science, 3520 San Martin Dr., Baltimore, MD 21218, USA. Electronic address: zheng@ciwemb.edu.
Yixian
Y
Zheng
D000595:Amino Acid Sequence; D000818:Animals; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics / Q000378:metabolism; D002877:Chromosomes, Human / Q000235:genetics*; D053595:Embryonic Stem Cells / Q000166:cytology / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D018386:Kinetochores / Q000378:metabolism*; D008677:Metaphase / Q000502:physiology; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D008870:Microtubules / Q000378:metabolism*; D008938:Mitosis / Q000502:physiology*; D008969:Molecular Sequence Data; D000075223:Poly-ADP-Ribose Binding Proteins; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D008941:Spindle Apparatus; D016335:Zinc Fingers / Q000235:genetics*
C584278:Bub1b protein, mouse; C489445:Bub3 protein, mouse; D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D008869:Microtubule-Associated Proteins; D000075223:Poly-ADP-Ribose Binding Proteins; C587673:ZNF207 protein, human; C068688:centromere protein E; D017346:Protein Serine-Threonine Kinases