The Role Of Cortactin In The Endocytosis Of Colon Cancer Cells

Objective:To investigate the role of Cortactin, a protein encoded by EMS1 oncogene, in the endocytosis of colon cancer cells.Methods:1. The distribution of Cortactin with Rab5 and Rab11 in human colon cancer cell HT29 was observed by confocal microscope.2. The distribution of Cortactin with internalized transferrin in human colon cancer cell HT29 was observed by confocal microscope.3. Human HT29 cells were divided into four groups: WT group was transfected with plasmids carried full length Cortactin, ND group was transfected with plasmids carried its mutant with N-terminal deletion, SD group was transfected with plasmids carried its mutant with C-terminal deletion, MGIN group was transfected with empty vector. The effect of these plasmids on cell endocytosis was tested by confocal microscope and capture-ELISA assay.4. The relation between the phosphorylation of Cortactin and transferrin endocytosis was analyzed by immunofluorescence assay. Results:1. Cortactin was associated with Rab5 and Rab 11 in HT29 cells.2. Cortactin was codistributed with internalized transferrin in HT29 cells .3. Compared with MGIN group, cell endocytosis of ND group and SD group was significant attenuated, while no apparent change was seen between WT group and MGIN group.4. The level of Cortactin phosphorylation was depended on the Tfn dose.Conclusion:Cortactin plays an important role in the endocytosis of colon cancer cells. The N- terminal or the C- terminal in the molecule is essential for the activity of cortactin in the process. In addition, the phosphorylation of cortactin is involved in the endocytosis of colon cancer cells, which is valuable for further study.