TGF

TGF is a widely used acronym that can refer to several different things, but in biology it most often denotes the transforming growth factor family, a group of cytokines that regulate cell growth, differentiation, and immune responses. The transforming growth factor beta (TGF-β) subgroup is the best studied and plays key roles in development, tissue homeostasis, and repair. Three mammalian TGF-β isoforms exist—TGF-β1, β2, and β3—each produced as a latent complex that requires activation to function.

The TGF superfamily includes TGF-βs as well as related factors such as activins, bone morphogenetic proteins (BMPs), and growth differentiation factors (GDFs). TGF-β signaling begins when active TGF-β binds to a type II receptor, which then recruits and phosphorylates a type I receptor (often ALK5/TGFBR1). This activates SMAD transcription factors, typically SMAD2 and SMAD3, which form a complex with SMAD4 and move to the nucleus to regulate gene expression. In addition to the canonical SMAD pathway, TGF-β can signal through SMAD-independent routes, including MAPK, Rho-like GTPases, and PI3K/AKT pathways.

Physiologically, TGF-β controls cell proliferation, differentiation, immune tolerance, and extracellular matrix production. It has critical functions during embryonic development and tissue repair but also contributes to pathology when signaling becomes dysregulated. In cancer, TGF-β can suppress early tumor growth yet promote invasion and metastasis in advanced disease. In fibrotic diseases, excessive TGF-β activity drives scar formation and matrix deposition.

Other uses of the acronym exist, such as The Global Fund to Fight AIDS, Tuberculosis and Malaria. In context, TGF typically refers to transforming growth factor and its signaling biology.