title: Divergent polo box domains underpin the unique kinetoplastid kinetochore.
abstract: Kinetochores are macromolecular machines that drive eukaryotic chromosome segregation by interacting with centromeric DNA and spindle microtubules. While most eukaryotes possess conventional kinetochore proteins, evolutionarily distant kinetoplastid species have unconventional kinetochore proteins, composed of at least 19 proteins (KKT1-19). Polo-like kinase (PLK) is not a structural kinetochore component in either system. Here, we report the identification of an additional kinetochore protein, KKT20, in Trypanosoma brucei. KKT20 has sequence similarity with KKT2 and KKT3 in the Cys-rich region, and all three proteins have weak but significant similarity to the polo box domain (PBD) of PLK. These divergent PBDs of KKT2 and KKT20 are sufficient for kinetochore localization in vivo. We propose that the ancestral PLK acquired a Cys-rich region and then underwent gene duplication events to give rise to three structural kinetochore proteins in kinetoplastids.
authors.affiliation: Department of Biochemistry, University of Oxford, Oxford, UK.
authors.forename: Olga O
authors.initials: OO
authors.lastname: Nerusheva
authors.affiliation: Department of Biochemistry, University of Oxford, Oxford, UK bungo.akiyoshi@bioch.ox.ac.uk.
authors.forename: Bungo
authors.identifier: http://orcid.org/0000-0001-6010-394X
authors.initials: B
authors.lastname: Akiyoshi
mesh_terms: D000595:Amino Acid Sequence; D018797:Cell Cycle Proteins / Q000032:analysis / Q000378:metabolism; D006801:Humans; D018386:Kinetochores / Q000737:chemistry* / Q000378:metabolism; D008938:Mitosis; D000072417:Protein Domains; D017346:Protein Serine-Threonine Kinases / Q000032:analysis / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000378:metabolism; D015800:Protozoan Proteins / Q000032:analysis* / Q000378:metabolism; D016415:Sequence Alignment; D014346:Trypanosoma brucei brucei / Q000737:chemistry / Q000166:cytology* / Q000378:metabolism; D014353:Trypanosomiasis, African / Q000469:parasitology; D000097869:Polo-Like Kinase 1
chemical_list: D018797:Cell Cycle Proteins; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D015800:Protozoan Proteins; D000097869:Polo-Like Kinase 1
keywords: DPB; Trypanosoma brucei; kinetochore; kinetoplastid; polo box domain; polo-like kinase