TGF-beta 3 (transforming growth factor beta 1) is one of three closely related mammalian members of the large TGF-beta superfamily that share a characteristic cystine knot structure . TGF-beta 1, -2 and -3 are highly pleiotropic cytokines that are proposed to act as cellular switches that regulate processes such as immune function, proliferation and epithelial-mesenchymal transition . Each TGF-beta isoform has some non?redundant functions; .Human TGF? beta 3 cDNA encodes a 412 amino acid (aa) precursor that contains a 23 aa signal peptide and a 389 aa proprotein . A furin?like convertase processes the proprotein to generate an N?terminal 277 aa latency?associated peptide (LAP) and a C?terminal 112 aa mature TGF? beta 3.