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Divergent polo boxes in KKT2 bind KKT1 to initiate the kinetochore assembly cascade in Trypanosoma brucei

Chromosome segregation requires assembly of the macromolecular kinetochore complex onto centromeric DNA. While most eukaryotes have canonical kinetochore proteins that are widely conserved among eukaryotes, evolutionarily divergent kinetoplastids have a unique set of kinetochore proteins. Little is...

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Detalles Bibliográficos
Autores principales: Ishii, Midori, Ludzia, Patryk, Marcianò, Gabriele, Allen, William, Nerusheva, Olga O., Akiyoshi, Bungo
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The American Society for Cell Biology 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9727816/
https://www.ncbi.nlm.nih.gov/pubmed/36129769
http://dx.doi.org/10.1091/mbc.E22-07-0269-T
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author Ishii, Midori
Ludzia, Patryk
Marcianò, Gabriele
Allen, William
Nerusheva, Olga O.
Akiyoshi, Bungo
author_facet Ishii, Midori
Ludzia, Patryk
Marcianò, Gabriele
Allen, William
Nerusheva, Olga O.
Akiyoshi, Bungo
author_sort Ishii, Midori
collection PubMed
description Chromosome segregation requires assembly of the macromolecular kinetochore complex onto centromeric DNA. While most eukaryotes have canonical kinetochore proteins that are widely conserved among eukaryotes, evolutionarily divergent kinetoplastids have a unique set of kinetochore proteins. Little is known about the mechanism of kinetochore assembly in kinetoplastids. Here we characterize two homologous kinetoplastid kinetochore proteins, KKT2 and KKT3, that constitutively localize at centromeres. They have three domains that are highly conserved among kinetoplastids: an N-terminal kinase domain of unknown function, the centromere localization domain in the middle, and the C-terminal domain that has weak similarity to polo boxes of Polo-like kinases. We show that the kinase activity of KKT2 is essential for accurate chromosome segregation, while that of KKT3 is dispensable for cell growth in Trypanosoma brucei. Crystal structures of their divergent polo boxes reveal differences between KKT2 and KKT3. We also show that the divergent polo boxes of KKT3 are sufficient to recruit KKT2 in trypanosomes. Furthermore, we demonstrate that the divergent polo boxes of KKT2 interact directly with KKT1 and that KKT1 interacts with KKT6. These results show that the divergent polo boxes of KKT2 and KKT3 are protein–protein interaction domains that initiate kinetochore assembly in T. brucei.
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spelling pubmed-97278162023-02-02 Divergent polo boxes in KKT2 bind KKT1 to initiate the kinetochore assembly cascade in Trypanosoma brucei Ishii, Midori Ludzia, Patryk Marcianò, Gabriele Allen, William Nerusheva, Olga O. Akiyoshi, Bungo Mol Biol Cell Articles Chromosome segregation requires assembly of the macromolecular kinetochore complex onto centromeric DNA. While most eukaryotes have canonical kinetochore proteins that are widely conserved among eukaryotes, evolutionarily divergent kinetoplastids have a unique set of kinetochore proteins. Little is known about the mechanism of kinetochore assembly in kinetoplastids. Here we characterize two homologous kinetoplastid kinetochore proteins, KKT2 and KKT3, that constitutively localize at centromeres. They have three domains that are highly conserved among kinetoplastids: an N-terminal kinase domain of unknown function, the centromere localization domain in the middle, and the C-terminal domain that has weak similarity to polo boxes of Polo-like kinases. We show that the kinase activity of KKT2 is essential for accurate chromosome segregation, while that of KKT3 is dispensable for cell growth in Trypanosoma brucei. Crystal structures of their divergent polo boxes reveal differences between KKT2 and KKT3. We also show that the divergent polo boxes of KKT3 are sufficient to recruit KKT2 in trypanosomes. Furthermore, we demonstrate that the divergent polo boxes of KKT2 interact directly with KKT1 and that KKT1 interacts with KKT6. These results show that the divergent polo boxes of KKT2 and KKT3 are protein–protein interaction domains that initiate kinetochore assembly in T. brucei. The American Society for Cell Biology 2022-11-18 /pmc/articles/PMC9727816/ /pubmed/36129769 http://dx.doi.org/10.1091/mbc.E22-07-0269-T Text en © 2022 Ishii et al. “ASCB®,” “The American Society for Cell Biology®,” and “Molecular Biology of the Cell®” are registered trademarks of The American Society for Cell Biology. https://creativecommons.org/licenses/by-nc-sa/4.0/This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial-Share Alike 4.0 International Creative Commons License.
spellingShingle Articles
Ishii, Midori
Ludzia, Patryk
Marcianò, Gabriele
Allen, William
Nerusheva, Olga O.
Akiyoshi, Bungo
Divergent polo boxes in KKT2 bind KKT1 to initiate the kinetochore assembly cascade in Trypanosoma brucei
title Divergent polo boxes in KKT2 bind KKT1 to initiate the kinetochore assembly cascade in Trypanosoma brucei
title_full Divergent polo boxes in KKT2 bind KKT1 to initiate the kinetochore assembly cascade in Trypanosoma brucei
title_fullStr Divergent polo boxes in KKT2 bind KKT1 to initiate the kinetochore assembly cascade in Trypanosoma brucei
title_full_unstemmed Divergent polo boxes in KKT2 bind KKT1 to initiate the kinetochore assembly cascade in Trypanosoma brucei
title_short Divergent polo boxes in KKT2 bind KKT1 to initiate the kinetochore assembly cascade in Trypanosoma brucei
title_sort divergent polo boxes in kkt2 bind kkt1 to initiate the kinetochore assembly cascade in trypanosoma brucei
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9727816/
https://www.ncbi.nlm.nih.gov/pubmed/36129769
http://dx.doi.org/10.1091/mbc.E22-07-0269-T
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