The serine 2481-autophosphorylated form of mammalian Target Of Rapamycin (mTOR) is localized to midzone and midbody in dividing cancer cells.
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.
Vazquez-Martin
Alejandro
A
Catalan Institute of Oncology (ICO Girona), Dr. Josep Trueta University Hospital of Girona, Avenida de Francia s/n, E-17007 Girona, Catalonia, Spain.
Oliveras-Ferraros
Cristina
C
Bernadó
Luis
L
López-Bonet
Eugeni
E
Menendez
Javier A
JA
D002352:Carrier Proteins / Q000378:metabolism*; D002455:Cell Division; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000201:enzymology; D049109:Cell Proliferation; D006801:Humans; D009369:Neoplasms / Q000378:metabolism* / Q000473:pathology*; D010766:Phosphorylation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism*; D012694:Serine / Q000378:metabolism*; D058570:TOR Serine-Threonine Kinases
D002352:Carrier Proteins; D012694:Serine; D017853:Phosphotransferases (Alcohol Group Acceptor); C546842:MTOR protein, human; D058570:TOR Serine-Threonine Kinases