Validation of SILAC results by Western-blotting. Proteins identified by SILAC were detected in nilotinib-sensitive Ks or nilotinib-resistant K-rn cell lysates. After transfer, specific proteins were individually detected for proteins over detected in K-rn (A) or down detected (B). After stripping, membranes were probed for actin as loading control. Proteins detected are indicated by an arrow on the left. Quantification of protein expression was performed by densitometry (C). Protein expression level was normalized using actin as loading control. Results are expressed as the mean fold increase expression for each protein by calculating the ratio of the K-rn cells to their sensitive counterpart Ks from at least 3 independent experiments. Significance was calculated by Mann Whitney test and indicated by an asterisk. Proteins identified by mass spectrometry and scored by SILAC were graphically represented as the ratio between the heavy and light isotope (D). Indicated proteins were immunoprecipitated from Ks or K-rn cell lysates. Tyrosine phosphorylated proteins were detected followed by the specific detection of immunoprecipitated proteins over detected in K-rn (E) or down detected (F). Results shown are from one independent experiment representative of 3.