Functional characterization of the Csm1-like protein TITAN 9 in Arabidopsis thaliana

Summary: Kinetochores are essential for chromosome segregation in eukaryotes. An important component of kinetochores in opisthokonta is Csm1. However, its function appears to be diversified and, while Csm1 in budding yeast is a component of the monopolin complex mediating mono-orientation of sister...

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Main Authors: Zhijian Zhang, Franziska Böwer, Shinichiro Komaki, Aladár Pettkó-Szandtner, Anastasiia O. Skuba, Eelco C. Tromer, Zoltán Magyar, Maren Heese, Arp Schnittger
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Language:English
Published: Elsevier 2025-09-01
Series:iScience
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Online Access:http://www.sciencedirect.com/science/article/pii/S2589004225015123
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author Zhijian Zhang
Franziska Böwer
Shinichiro Komaki
Aladár Pettkó-Szandtner
Anastasiia O. Skuba
Eelco C. Tromer
Zoltán Magyar
Maren Heese
Arp Schnittger
author_facet Zhijian Zhang
Franziska Böwer
Shinichiro Komaki
Aladár Pettkó-Szandtner
Anastasiia O. Skuba
Eelco C. Tromer
Zoltán Magyar
Maren Heese
Arp Schnittger
author_sort Zhijian Zhang
collection DOAJ
description Summary: Kinetochores are essential for chromosome segregation in eukaryotes. An important component of kinetochores in opisthokonta is Csm1. However, its function appears to be diversified and, while Csm1 in budding yeast is a component of the monopolin complex mediating mono-orientation of sister kinetochores during meiosis I, the fission yeast homolog Pcs1 prevents merotelic spindle microtubule attachments during mitosis and meiosis II. Here, we have characterized TITAN9 (TTN9), a distantly related Csm1-like protein in the flowering plant Arabidopsis. TTN9 accumulates in mitotic and meiotic tissue and localizes to centromeres throughout the cell cycle. By analyzing proteome-wide TTN9 associated proteins, we identified a substantial subset of the Arabidopsis kinetochore proteome, including DSN1, mirroring known Csm1 interactions in yeast. While homozygous ttn9 mutants are not viable, a meiosis-specific knock-down of TTN9 causes chromosome segregation defects and split centromeres during meiosis I. These findings suggest that Csm1-like proteins contribute to conserved kinetochore functions across eukaryotes.
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spelling doaj-art-017c2d878d644f8f8d8c0f874e261d382025-08-20T03:41:36ZengElsevieriScience2589-00422025-09-0128911325110.1016/j.isci.2025.113251Functional characterization of the Csm1-like protein TITAN 9 in Arabidopsis thalianaZhijian Zhang0Franziska Böwer1Shinichiro Komaki2Aladár Pettkó-Szandtner3Anastasiia O. Skuba4Eelco C. Tromer5Zoltán Magyar6Maren Heese7Arp Schnittger8Department of Developmental Biology, Institute for Plant Sciences and Microbiology, University of Hamburg, 22609 Hamburg, GermanyDepartment of Developmental Biology, Institute for Plant Sciences and Microbiology, University of Hamburg, 22609 Hamburg, GermanyGraduate School of Science and Technology, Nara Institute of Science and Technology, Nara 630-0192, JapanProteomics Research Group, Core Facility, HUN-REN Biological Research Centre, 6726 Szeged, HungaryDepartment of Developmental Biology, Institute for Plant Sciences and Microbiology, University of Hamburg, 22609 Hamburg, GermanyCell Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute, Faculty of Science and Engineering, University of Groningen, Groningen, the NetherlandsInstitute of Plant Biology, HUN-REN Biological Research Centre, 6726 Szeged, HungaryDepartment of Developmental Biology, Institute for Plant Sciences and Microbiology, University of Hamburg, 22609 Hamburg, Germany; Corresponding authorDepartment of Developmental Biology, Institute for Plant Sciences and Microbiology, University of Hamburg, 22609 Hamburg, Germany; Corresponding authorSummary: Kinetochores are essential for chromosome segregation in eukaryotes. An important component of kinetochores in opisthokonta is Csm1. However, its function appears to be diversified and, while Csm1 in budding yeast is a component of the monopolin complex mediating mono-orientation of sister kinetochores during meiosis I, the fission yeast homolog Pcs1 prevents merotelic spindle microtubule attachments during mitosis and meiosis II. Here, we have characterized TITAN9 (TTN9), a distantly related Csm1-like protein in the flowering plant Arabidopsis. TTN9 accumulates in mitotic and meiotic tissue and localizes to centromeres throughout the cell cycle. By analyzing proteome-wide TTN9 associated proteins, we identified a substantial subset of the Arabidopsis kinetochore proteome, including DSN1, mirroring known Csm1 interactions in yeast. While homozygous ttn9 mutants are not viable, a meiosis-specific knock-down of TTN9 causes chromosome segregation defects and split centromeres during meiosis I. These findings suggest that Csm1-like proteins contribute to conserved kinetochore functions across eukaryotes.http://www.sciencedirect.com/science/article/pii/S2589004225015123plant geneticsplant bioinformaticsplant Biologyplant physiologyplant systematicsplant evolution
spellingShingle Zhijian Zhang
Franziska Böwer
Shinichiro Komaki
Aladár Pettkó-Szandtner
Anastasiia O. Skuba
Eelco C. Tromer
Zoltán Magyar
Maren Heese
Arp Schnittger
Functional characterization of the Csm1-like protein TITAN 9 in Arabidopsis thaliana
iScience
plant genetics
plant bioinformatics
plant Biology
plant physiology
plant systematics
plant evolution
title Functional characterization of the Csm1-like protein TITAN 9 in Arabidopsis thaliana
title_full Functional characterization of the Csm1-like protein TITAN 9 in Arabidopsis thaliana
title_fullStr Functional characterization of the Csm1-like protein TITAN 9 in Arabidopsis thaliana
title_full_unstemmed Functional characterization of the Csm1-like protein TITAN 9 in Arabidopsis thaliana
title_short Functional characterization of the Csm1-like protein TITAN 9 in Arabidopsis thaliana
title_sort functional characterization of the csm1 like protein titan 9 in arabidopsis thaliana
topic plant genetics
plant bioinformatics
plant Biology
plant physiology
plant systematics
plant evolution
url http://www.sciencedirect.com/science/article/pii/S2589004225015123
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