Relocalization of human chromatin remodeling cofactor TIP48 in mitosis

Exp Cell Res. 2005 Nov 1;310(2):357-69. doi: 10.1016/j.yexcr.2005.07.030. Epub 2005 Sep 12.


TIP48 is a highly conserved eukaryotic AAA+ protein which is an essential cofactor for several complexes involved in chromatin acetylation and remodeling, transcriptional and developmental regulation and nucleolar organization and trafficking. We show that TIP48 abundance in HeLa cells did not change during the cell cycle, nor did its distribution in various biochemical fractions. However, we observed distinct changes in the subcellular localization of TIP48 during M phase using immunofluorescence microscopy. Our studies demonstrate that in interphase cells TIP48 was found mainly in the nucleus and exhibited a distinct localization in the nuclear periphery. As the cells entered mitosis, TIP48 was excluded from the condensing chromosomes but showed association with the mitotic apparatus. During anaphase, some TIP48 was detected in the centrosome colocalizing with tubulin but the strongest staining appeared in the mitotic equator associated with the midzone central spindle. Accumulation of TIP48 in the midzone and the midbody was observed in late telophase and cytokinesis. This redeployment of TIP48 during anaphase and cytokinesis was independent of microtubule assembly. The relocation of endogenous TIP48 to the midzone/midbody under physiological conditions suggests a novel and distinct function for TIP48 in mitosis and possible involvement in the exit of mitosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATPases Associated with Diverse Cellular Activities
  • Carrier Proteins / analysis*
  • Carrier Proteins / metabolism*
  • Cell Cycle
  • Cell Nucleus / chemistry
  • Cell Nucleus / metabolism
  • Centrosome / chemistry
  • Centrosome / metabolism
  • Chromatin Assembly and Disassembly*
  • Cytokinesis
  • DNA Helicases / analysis*
  • DNA Helicases / metabolism*
  • HeLa Cells
  • Humans
  • Microtubules / metabolism
  • Mitosis*
  • Spindle Apparatus / chemistry*
  • Spindle Apparatus / metabolism
  • Tubulin / analysis


  • Carrier Proteins
  • Tubulin
  • ATPases Associated with Diverse Cellular Activities
  • DNA Helicases
  • RUVBL2 protein, human