Figure 2. Yes and Lyn SFK family members are overexpressed in Ctx^R cells.

(A) Yes and Lyn mRNA is up-regulated in Ctx^R clones (HC1, HC4, and HC8). Lyn (3.6~4.5-fold), Yes (~1.5-fold) and Src (−2.3~−3.5-fold) mRNA expression levels were compared to that of the Ctx^S cell line (HP) by qPCR. (B) Total protein levels of Yes and Lyn were increased (1.3~2.1-fold) in Ctx^R clones (HC1, HC4, and HC8) as compared to the Ctx^S cell line (HP). Cells were harvested and protein lysates were fractionated on SDS-PAGE followed by immunoblotting for the indicated proteins. α-tubulin was used as a loading control. Protein expression was quantitated using ImageJ software. (C) Analysis of EGFR binding partners in Ctx^R cells using immunoprecipitation assay indicated that EGFR displayed increased binding with Yes and Lyn as compared to the Ctx^S parental cell line. Cells were harvested and EGFR or IgG were immunoprecipitated with anti-mouse EGFR antibody or normal mouse IgG. The immunoprecipitate complexes were fractionated on SDS-PAGE followed by immunoblotting for indicated proteins.