Fibroblast growth factor receptor 1-4 tyrosine kinase domains (FGFR1-4 TKDs)

The Fibroblast growth factor receptor 1-4 (FGFR1-4) tyrosine kinase domains are the intracellular catalytic components of a family of four highly conserved receptor tyrosine kinases (RTKs) [1, 14]. These domains are responsible for the trans-phosphorylation of specific tyrosine residues upon ligand-induced receptor dimerization, which serves as a critical trigger for downstream signaling cascades including the RAS-MAPK, PI3K-AKT, and PLCγ pathways [5, 10]. In normal physiology, FGFR signaling is essential for processes such as embryonic development, angiogenesis, and tissue repair [2, 13]. However, genetic alterations—including gene fusions, activating mutations, and amplifications—can lead to the constitutive activation of these kinase domains, driving oncogenesis in various malignancies such as cholangiocarcinoma, urothelial carcinoma, and squamous cell lung cancer [6, 7]. Therapeutic targeting of these domains primarily involves small-molecule tyrosine kinase inhibitors (TKIs) that compete with ATP for binding, thereby blocking autophosphorylation and suppressing tumor growth [5, 13].

Other names

FGFR1FGFR2FGFR3FGFR4CD331CD332CD333CD334Fibroblast growth factor receptor 1Fibroblast growth factor receptor 2Fibroblast growth factor receptor 3Fibroblast growth factor receptor 4FLT2BEKCEK2JTK2

ATP-competitive inhibition of the intracellular tyrosine kinase domains, which prevents receptor autophosphorylation and the subsequent recruitment of adapter proteins (e.g., FRS2), thereby blocking the activation of downstream oncogenic signaling pathways such as MAPK, PI3K/AKT, and STAT [5, 13, 14].