Figure 4: Analysis of Ras-mitogen-activated protein kinase-ERK pathway in sarcoid-derived cell lines (EqS). (a) Immunoblotting analysis of Ras in a pull-down assay of activated Ras (Raf1-RBD-Ras). Raf1-RBD-Ras was increased in cell lines EqS01a (to higher extent), EqS02aE5, and EqS04b when compared to EqS02a (not expressing E5). Total Ras levels were detected on whole cell lysates before pull-down assay to allow normalization of Raf1-RBD-Ras. Ras was overexpressed in EqS01a. Ras expression levels were normalized to actin levels. (b) Quantitative densitometric analysis of the bands was performed with Image Lab software (ChemiDoc, Bio-Rad Laboratories). (c) Immunoblotting analysis of pMEK and pERK expression. No differences in phosphorylation status of both MEK and ERK kinases were recorded. Actin protein levels were detected to ensure equal amounts of proteins for each lane.