Human Zwint-1 specifies localization of Zeste White 10 to kinetochores and is essential for mitotic checkpoint signaling

J Biol Chem. 2004 Dec 24;279(52):54590-8. doi: 10.1074/jbc.M407588200. Epub 2004 Oct 13.


Chromosome segregation in mitosis is orchestrated by dynamic interaction between spindle microtubules and the kinetochore, a multiprotein complex assembled onto centromeric DNA of the chromosome. Here we show that Zwint-1 is required and is sufficient for kinetochore localization of Zeste White 10 (ZW10) in HeLa cells. Zwint-1 specifies the kinetochore association of ZW10 by interacting with its N-terminal domain. Suppression of synthesis of Zwint-1 by small interfering RNA abolishes the localization of ZW10 to the kinetochore, demonstrating the requirement of Zwint-1 for ZW10 kinetochore localization. In addition, depletion of Zwint-1 affects no mitotic arrest but causes aberrant premature chromosome segregation. These Zwint-1-suppressed cells display chromosome bridge phenotype with sister chromatids inter-connected. Moreover, Zwint-1 is required for stable association of CENP-F and dynamitin but not BUB1 with the kinetochore. Finally, our studies show that Zwint-1 is a new component of the mitotic check-point, as cells lacking Zwint-1 fail to arrest in mitosis when exposed to microtubule inhibitors, yielding interphase cells with multinuclei. As ZW10 and Zwint-1 are absent from yeast, we reasoned that metazoans evolved an elaborate spindle checkpoint machinery to ensure faithful chromosome segregation in mitosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Binding Sites
  • Carrier Proteins / analysis
  • Carrier Proteins / genetics
  • Carrier Proteins / physiology*
  • Chromosomal Proteins, Non-Histone / analysis
  • Chromosomal Proteins, Non-Histone / genetics
  • Chromosomal Proteins, Non-Histone / metabolism*
  • Chromosome Segregation / physiology
  • Dynactin Complex
  • Gene Expression
  • Glutathione Transferase / genetics
  • Green Fluorescent Proteins / genetics
  • HeLa Cells
  • Humans
  • Intracellular Signaling Peptides and Proteins
  • Kinetochores / chemistry
  • Kinetochores / metabolism*
  • Mice
  • Mice, Inbred BALB C
  • Microfilament Proteins
  • Microtubule-Associated Proteins / analysis
  • Microtubule-Associated Proteins / genetics
  • Microtubule-Associated Proteins / metabolism*
  • Mitosis / physiology*
  • Nuclear Proteins
  • Peptide Fragments / metabolism
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / physiology
  • Recombinant Fusion Proteins
  • Signal Transduction / physiology*
  • Transfection


  • Carrier Proteins
  • Chromosomal Proteins, Non-Histone
  • DCTN2 protein, human
  • Dctn2 protein, mouse
  • Dynactin Complex
  • Intracellular Signaling Peptides and Proteins
  • Microfilament Proteins
  • Microtubule-Associated Proteins
  • Nuclear Proteins
  • Peptide Fragments
  • RNA, Small Interfering
  • Recombinant Fusion Proteins
  • ZW10 protein, human
  • ZWINT protein, human
  • centromere protein F
  • green fluorescent protein, Aequorea victoria
  • Green Fluorescent Proteins
  • Glutathione Transferase