Figure 4

Schematic illustration of the involvement of c-Ski and TGF-β signaling pathway in nurse cell formation. Binding of TGF-β by the type II receptor on the cell surface initiates a cascade of signaling events. Activated type I receptor phosphorylates Smad2 and Smad3 in the cytoplasm, which forms a complex with Smad4. The Smad2/3/4 complex moves to the nucleus and functionally collaborates with distinct transcription factors to turn on or off transcription of many TGF-β-responsive genes. C-Ski acts as a co-repressor to turn off the transcription, which results in the cell cycle arrest and transformation of Trichinella infected muscle cells. This figure referred the review by Shi and Massague [97].