The absence of latent transforming growth factor-beta binding protein–1 (LTBP–1) inhibits TGF-beta secretion

Aims: Latent transforming growth factor (TGF)-β binding proteins (LTBPs) play important roles in the secretion and activation of TGF-β, which is a key factor in wound healing and fibrosis. TGF-β is synthesized as latent high-molecular weight complex, composed of TGF-β, a part of the TGF-β precursor, and the latent TGF-β binding protein. LTBP for itself is an ingredient of the extracellular matrix, targets TGF-β thither, and participates in the activation of free TGF-β. We have previously shown that mice lacking LTBP–1 are less prone to hepatic fibrogenesis [1]. To understand the underlying mechanisms, we here examined the capability of embryonic cells from wildtype and LTBP–1 knockout mice to secrete active TGF-β.