FLT3, PDGFRα, PDGFRβ, and c-Kit (FLT3, PDGFRα, PDGFRβ, KIT (or c-Kit))

Each receptor in this group is a class III receptor tyrosine kinase comprising five extracellular immunoglobulin-like domains, a single transmembrane domain, and a split intracellular tyrosine kinase domain. Upon binding their respective ligands (e.g., stem cell factor for KIT, PDGF isoforms for PDGFRs, FLT3 ligand for FLT3), these receptors dimerize and trigger intracellular phosphorylation, initiating diverse signaling cascades fundamental to hematopoiesis, cell proliferation, differentiation, and migration. Mutations, overexpression, or constitutive activation are frequently implicated in cancer and other diseases, and each receptor is a validated therapeutic target for multiple classes of tyrosine kinase inhibitors.

Other names

FMS-like tyrosine kinase 3CD135PDGFRACD140aPDGFRBCD140bKITCD117Stem cell factor receptor

Tyrosine kinase inhibition (competitive binding at ATP site) Blockade of downstream signaling (prevents activation of proliferation/survival pathways) Some inhibitors bind preferentially to active or inactive receptor conformations