The serine 2481-autophosphorylated form of mammalian Target Of Rapamycin (mTOR) is localized to midzone and midbody in dividing cancer cells

Biochem Biophys Res Commun. 2009 Mar 13;380(3):638-43. doi: 10.1016/j.bbrc.2009.01.153. Epub 2009 Jan 29.

Abstract

Using a high-resolution, automated confocal high-content imaging system, we investigated the sub-cellular localization of the Serine 2481-autophosphorylated form of mTOR (PP-mTOR(Ser2481)) during mitosis and cytokinesis in human cancer cells. PP-mTOR(Ser2481) exhibited a punctate nuclear distribution in interphase cancer cells, with the number of PP-mTOR(Ser2481) nuclear speckles positively relating with the proliferative capacity of cancer cells. PP-mTOR(Ser2481) expression dynamically rearranged within the cytoplasm in a close association near and between separating chromosomes during early stages of mitosis. Towards the end of anaphase and in telophase, PP-mTOR(Ser2481) drastically focused on the midzone and ultimately in the centre of the midbody at the presumptive cleavage furrow. In cells at cytokinesis, PP-mTOR(Ser2481) appeared as a doublet facing each other at the apical ends of two daughter cells. Three-dimensional analysis confirmed that PP-mTOR(Ser2481) positioned at a ring structure wrapped round by microtubule bundles to connect daughter cells. These results reveal for the first time that PP-mTOR(Ser2481) may be unexpectedly involved in the terminal stages of cytokinesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carrier Proteins / metabolism*
  • Cell Division
  • Cell Line, Tumor
  • Cell Nucleus / enzymology
  • Cell Proliferation
  • Humans
  • Neoplasms / metabolism*
  • Neoplasms / pathology*
  • Phosphorylation
  • Phosphotransferases (Alcohol Group Acceptor) / metabolism*
  • Serine / metabolism*
  • TOR Serine-Threonine Kinases

Substances

  • Carrier Proteins
  • Serine
  • Phosphotransferases (Alcohol Group Acceptor)
  • MTOR protein, human
  • TOR Serine-Threonine Kinases