Figure 1From: Activation of MEK1 or MEK2 isoform is sufficient to fully transform intestinal epithelial cells and induce the formation of metastatic tumors Expression of activated MEK1 or MEK2 morphologically transforms intestinal epithelial cells. IEC-6 cells were infected with retroviruses encoding the indicated MEK constructs and populations of puromycine-resistant cells were selected for further analysis. (A) Expression of HA-tagged MEK1 and MEK2 was analyzed by immunoblotting with anti-HA antibody. (B) Expression of MEK1 and MEK2 was analyzed by immunoblotting with specific antibodies. (C) The ectopically expressed MEK proteins were immunoprecipitated with anti-HA antibody, and phosphotransferase activity was measured using an ERK2 reactivation assay. Results are representative of at least three independent experiments. (D) Morphology of exponentially proliferating IEC-6 cells stably expressing the indicated MEK constructs was examined by phase-contrast microscopy. (E) Immunofluorescence analysis of E-cadherin and vimentin expression. (F) Expression of E-cadherin, cytokeratins, vimentin and smooth muscle α-actin was analyzed by immunoblotting in the indicated cell lines. α-Tubulin was used as loading control. (G) Quantitative PCR analysis of E-cadherin mRNA levels. Expression levels are expressed as fold-increase relative to vector-infected cells.Back to article page