Vascular Endothelial Growth Factor Receptors, VEGFRs

Vascular Endothelial Growth Factor Receptors (VEGFRs) are receptors for vascular endothelial growth factor (VEGF). There are three main subtypes of VEGFR, numbered 1, 2 and 3. Depending on alternative splicing, they may be membrane-bound (mbVEGFR) or soluble (sVEGFR).The VEGF receptors have an extracellular portion consisting of 7 immunoglobulin-like domains, a single transmembrane spanning region and an intracellular portion containing a split tyrosine-kinase domain. VEGFR-2 appears to mediate almost all of the known cellular responses to VEGF. The function of VEGFR-1 is less well defined, although it is thought to modulate VEGFR-2 signaling. Another function of VEGFR-1 is to act as a dummy/decoy receptor, sequestering VEGF from VEGFR-2 binding. In fact, an alternatively spliced form of VEGFR-1 (sFlt1) is not a membrane bound protein but is secreted and functions primarily as a decoy. VEGFR-3 mediates lymphangiogenesis in response to VEGF-C and VEGF-D. Inhibitors of VEGFR are used in the treatment of cancer.