VEGF Receptor 2 protein, also known as VEGFR-2 or Flk-1, is a receptor tyrosine kinase that plays a crucial role in angiogenesis, vascular development, and embryonic hematopoiesis. It is the main receptor for vascular endothelial growth factors (VEGFs), such as VEGFA, VEGFC, and VEGFD. VEGFR-2 is expressed widely, particularly in vascular endothelial cells and hemangioendotheliomas. It is localized in the endoplasmic reticulum and cell membrane. VEGFR-2 mediates the VEGF-induced proliferation, survival, migration, tube formation, and sprouting of endothelial cells, which are critical steps in angiogenesis and vascular development. The main function of VEGFR-2 is to regulate the growth and development of endothelial cells through signal transduction. This process involves dynamic interactions between various proteins and signaling pathways. Some of the major signaling pathways associated with VEGFR-2 include the PI3K-Akt, Ras-Raf-MEK-ERK, PKC-STAT3, and JAK2-STAT3 pathways.