Vazquez-Martin Alejandro, Oliveras-Ferraros Cristina, Bernadó Luis, López-Bonet Eugeni, Menendez Javier A
Catalan Institute of Oncology (ICO Girona), Dr. Josep Trueta University Hospital of Girona, Avenida de Francia s/n, E-17007 Girona, Catalonia, Spain.
Biochem Biophys Res Commun. 2009 Mar 13;380(3):638-43. doi: 10.1016/j.bbrc.2009.01.153. Epub 2009 Jan 29.
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.
我们使用高分辨率的自动化共聚焦高内涵成像系统，研究了丝氨酸2481自磷酸化形式的mTOR（PP-mTOR(Ser2481)）在人癌细胞有丝分裂和胞质分裂过程中的亚细胞定位。PP-mTOR(Ser2481)在间期癌细胞中呈现点状核分布，PP-mTOR(Ser2481)核斑点的数量与癌细胞的增殖能力呈正相关。在有丝分裂早期，PP-mTOR(Ser2481)的表达在细胞质内动态重排，紧密关联于分离的染色体附近和之间。在后期末期和末期，PP-mTOR(Ser2481)急剧聚焦于中间区，并最终位于假定分裂沟处中体的中心。在胞质分裂的细胞中，PP-mTOR(Ser2481)在两个子细胞的顶端呈现为相互面对的双联体。三维分析证实，PP-mTOR(Ser2481)定位在由微管束包裹的环状结构中，以连接子细胞。这些结果首次揭示PP-mTOR(Ser2481)可能意外地参与胞质分裂的末期阶段。
