TGF-β: structure, latency, activation, and receptors.17,67 

LAP indicates latency-associated peptide; LTBP, latent TGF-β binding protein; M6P/IGFII-R, mannose-6-phosphate/type II insulin-like growth factor receptor; PLg, plasminogen; PL, plasmin; Smad, TGF-β signal transduction proteins; Anti-Smad, antagonistic Smad; Co-Smad, common-partner Smad; R-Smad, receptor-regulated Smad; TGase, transglutaminase; TβR-I, -II, -III, TGF-β receptor type I, II, III; TSP, thrombospondin; uPA, urokinase plasminogen activator; and uPA-R, uPA receptor.