Expression of Truncated Latent TGF-β-Binding Protein Modulates TGF-β Signaling

The study explored the impact of truncated latent TGF-β-binding protein (LTBP-1) on TGF-β signaling, particularly in hair follicle development in mice. By overexpressing a truncated form of LTBP-1 (ECR3E-Myc), researchers found increased TGF-β signaling, evidenced by more pSmad2/3-positive nuclei, leading to reduced keratinocyte proliferation, shorter hair, and early growth arrest. This was due to the truncated protein's inability to incorporate latent TGF-β into the extracellular matrix (ECM), causing inappropriate TGF-β activation. The study highlighted LTBP-1's crucial role in regulating TGF-β signaling by controlling its sequestration in the ECM, essential for proper hair follicle morphogenesis and growth.