sentences:  Normally mature TGFβ is secreted as a latent complex with its N-terminal fragment, latency-associated peptide (LAP), which inhibits its activity.The latent complex is covalently linked to the extracellular matrix by binding to latent TGF-β-binding proteins.TGF-β is activated by diverse mechanisms in the lung, ultimately involving either proteolysis or conformational alteration of the LAP.