Transforming growth factor beta 1 (TGF-β1) signaling axis (TGF-β1 axis)

The Transforming growth factor beta 1 (TGF-β1) signaling axis is a pleiotropic pathway that serves as a master regulator of cell fate, immune homeostasis, and tissue repair [UniProt: P01137]. Signaling is initiated by the binding of the TGF-β1 ligand to a heteromeric receptor complex consisting of TGF-β type I (TGFBR1) and type II (TGFBR2) receptors, which triggers the phosphorylation of SMAD2 and SMAD3 proteins [PubMed: 30635447]. These activated SMADs form a complex with SMAD4 and translocate to the nucleus to regulate the transcription of genes involved in the cell cycle, extracellular matrix production, and epithelial-mesenchymal transition (EMT) [PubMed: 29133304]. In the context of disease, the axis is a primary driver of organ fibrosis and plays a dual role in oncology; it acts as a tumor suppressor in early stages but promotes metastasis and immune evasion in advanced cancers [PubMed: 22437938]. Therapeutic strategies targeting this axis include neutralizing antibodies, small molecule kinase inhibitors, and bifunctional fusion proteins designed to block TGF-β-mediated immunosuppression and fibrotic progression [PubMed: 31092557]. However, the clinical development of these agents is complicated by the pathway's essential role in normal tissue homeostasis, leading to potential side effects such as cardiotoxicity and skin lesions.

Other names

TGFB1 signaling pathwayTGF-beta 1/SMAD signaling axisTransforming growth factor beta-1TGFB1CEDLAPDPD1

Drugs targeting this axis function by neutralizing the TGF-β ligands with monoclonal antibodies, inhibiting the kinase activity of the TGF-β type I receptor (ALK5) using small molecules, or employing decoy receptors (TGF-β traps) to sequester ligands, thereby preventing the phosphorylation of SMAD2/3 and subsequent transcriptional activation of target genes [PubMed: 28115516, PubMed: 31092557].