Human TGF-β3 precursor consists of two disulfide-linked identical subunits with 412 amino acids each. The carboxy-terminal (112 residues) of TGF-β3 represents the biologically active form of this protein; this portion of TGF-β3 exhibits 86/112 and 89/112 identical residues compared with TGF-β1 and TGF-β2, respectively. TGF-β3 precursor is cleaved by furin, and localized in the residue 300 of the trans-Golgi network. Furin processes the TGF-β3 precursor at the carboxyl side of the consensus sequence RKKR which precedes the NH2-terminal Ala 301 residue of the mature TGF-β3. The TGF-β3 precursor includes (in the N-terminal portion) the latency-associated peptide (LAP dimer) and (in the C-terminal) the 25 kD portion that constitutes the mature TGF-β3. The LAP dimer and the TGF-β3 mature protein remain non-covalently associated after furin cleavage, and this complex does not bind to the TFG-β receptor. In addition, the TGF-β3 latent complex is joined covalently through LAP to LTBP. The TGF-β1 active form requires dissociation from LAP. Some activators can release TGF-β1 from LAP, such as thrombospondin-1, reactive oxygen species, and the integrins avb6 and avb8, and these activators might release TGF-β3 through similar mechanism. TGF-β3 induces biomechanical remodeling in avian embryonic atrioventricular valves. Also, gene delivery of a mutant TGF-β3 reduces re-epithelialization density and fibroblast/myofibroblast transdifferentiation within the wound area, both mechanisms are indicative of reduced scar tissue formation. In fact, recombinant TGF-β3 has been used in clinical trials as prophylactic treatment of human scars.