Fibroblast growth factor receptor 1, Fibroblast growth factor receptor 2, Fibroblast growth factor receptor 3, and Fibroblast growth factor receptor 4 (FGFR1, FGFR2, FGFR3, FGFR4)

Fibroblast growth factor receptors (FGFR1, FGFR2, FGFR3, FGFR4) are single-pass transmembrane receptor tyrosine kinases that function as critical mediators of cellular response to fibroblast growth factors (FGFs). Each receptor possesses an extracellular ligand-binding domain with three immunoglobulin (Ig)-like repeats, a transmembrane domain, and an intracellular split tyrosine kinase domain. Upon ligand binding, FGFRs dimerize and autophosphorylate, triggering multiple downstream signaling cascades—most prominently the MAPK, PI3K-AKT, and PLCγ pathways. FGFR signaling governs cell proliferation, differentiation, survival, angiogenesis, and metabolic homeostasis. Abnormal FGFR function—due to mutations, amplifications, or gene fusions—is implicated in various cancers and developmental disorders, making these receptors important therapeutic targets for selective FGFR inhibitors.

Other names

FGFR-1FGFR-2FGFR-3FGFR-4CD331 (FGFR1)CD332 (FGFR2)CD333 (FGFR3)CEKFLGTKFJTK2 (FGFR2)JTK4 (FGFR3)hydroxyaryl-protein kinaseHBGFR

Inhibition of receptor tyrosine kinase activity blocks downstream signal transduction (e.g., MAPK, PI3K-AKT, PLCγ pathways), leading to downregulation of cell proliferation and survival signals in tumors harboring FGFR alterations.