Characterization of a MAPKK-like protein kinase TOPK

Biochem Biophys Res Commun. 2004 Dec 17;325(3):997-1004. doi: 10.1016/j.bbrc.2004.10.133.


A MAPKK-like protein kinase TOPK expresses in a wide range of proliferating cells and tissues such as cancer cells and testis. However, details of this kinase are still uncovered. We investigated the intracellular distribution of TOPK and its association with cdk1/cyclin B and microtubules. In interphase cells, TOPK expresses in cytosol and nucleus without any significant association with microtubule networks. During mitosis, TOPK-Thr-9 was phosphorylated by cdk1/cyclin B and TOPK significantly associates with mitotic spindles. When TOPK expression was suppressed, formation of spindle midzone was thinned and dimmed and cytokinesis was disturbed. We propose that TOPK plays a role in the formation of spindle midzone and in cytokinesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • COS Cells
  • Cell Cycle*
  • Cell Line, Tumor
  • Chlorocebus aethiops
  • Cyclin B / genetics
  • Cyclin B / metabolism*
  • HeLa Cells
  • Humans
  • Microtubules / metabolism
  • Mitogen-Activated Protein Kinase Kinases
  • Osteosarcoma / enzymology*
  • Osteosarcoma / pathology*
  • Phosphorylation
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism*
  • Species Specificity


  • Cyclin B
  • Protein-Serine-Threonine Kinases
  • Mitogen-Activated Protein Kinase Kinases
  • PDZ-binding kinase