Transforming growth factor beta type II receptor and transforming growth factor beta type I receptor (TGF-β type II receptor (TGFBR2) and TGF-β type I receptor (TGFBR1 or ALK5))

Transforming growth factor beta (TGF-β) signals through a heterotetrameric complex composed of two type II receptors (TGFBR2) and two type I receptors (TGFBR1/ALK5). TGFBR2 binds TGF-β ligand with high affinity, recruits and phosphorylates TGFBR1 in the GS domain, activating its serine/threonine kinase function. This triggers phosphorylation of SMAD2 and SMAD3, which then complex with SMAD4, translocate to the nucleus, and regulate gene expression involved in cell growth, differentiation, apoptosis, and tissue remodeling. Dysregulation of TGF-β receptor signaling is implicated in cancer, fibrosis, immune disorders, and vascular disease, making both TGFBR1 and TGFBR2 critical targets for therapeutic modulation.

Other names

TGF-β type II receptor: TGFBR2, TβRIITGF-β type I receptor: TGFBR1, ALK5, TβRI, Activin receptor-like kinase 5TGF-β receptors (when referring to both together)

Small molecule inhibitors block the kinase activity of TGFBR1 (ALK5), thus preventing phosphorylation of SMAD2/3 and downstream signaling. Antibodies or ligand traps block ligand binding or neutralize TGF-β in the extracellular environment, preventing complex assembly.