TGF-β is a profibrotic growth factor that is a critical mediator of the epithelial to mesenchymal cell transition (EMT). There are three major types of TGF-β receptors, type I TGF-β receptors (TBRIs) and type II TGF-β receptors (TBRIIs) which are transmembrane serine/threonine kinase receptors, and coreceptors, type III TGF-β receptors (TBRIIIs).