Cell cycle-dependent translocation of PRC1 on the spindle by Kif4 is essential for midzone formation and cytokinesis

Proc Natl Acad Sci U S A. 2005 Jan 11;102(2):343-8. doi: 10.1073/pnas.0408438102. Epub 2004 Dec 29.


The spindle midzone, a conspicuous network of antiparallel interdigitating nonkinetochore microtubules between separating chromosomes, plays a crucial role in regulating the initiation and completion of cytokinesis. In this study, we report the use of time-lapse microscopy and a human kinesin endoribonucleases RNase III-prepared short interfering RNA (esiRNA) library to identify Kif4 as a motor protein that translocates PRC1, a spindle midzone-associated cyclin-dependent kinase substrate protein, to the plus ends of interdigitating spindle microtubules during the metaphase-to-anaphase transition. We show that Kif4 binds to PRC1 through its "stalk plus tail" domains and Kif4 and PRC1 colocalize on the spindle midzone/midbody during anaphase and cytokinesis. Suppression of Kif4 expression by Kif4 esiRNA results in the inhibition of PRC1 translocation, a block of the midzone formation, and a failure of cytokinesis. PRC1 translocation and midzone formation can be restored, and the cytokinetic defects can be rescued in Kif4 esiRNA-treated cells by coexpression of Kif4 but not its motor dead mutant Kif4md. Furthermore, we show that cyclin-dependent kinase phosphorylation of PRC1 controls the timing of PRC1 translocation by Kif4. These results, in light of the crucial role of PRC1 in midzone formation, indicate that cell cycle-dependent translocation of PRC1 by Kif4 is essential for midzone formation and cytokinesis.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cell Cycle Proteins / metabolism*
  • Cell Cycle*
  • Cyclin-Dependent Kinases / physiology
  • Cytokinesis*
  • HeLa Cells
  • Humans
  • Kinesins / physiology*
  • Mitosis
  • Phosphorylation
  • Protein Transport
  • Spindle Apparatus / metabolism*


  • Cell Cycle Proteins
  • PRC1 protein, human
  • Cyclin-Dependent Kinases
  • KIF4A protein, human
  • KIF4B protein, human
  • Kinesins