Tyrosine-protein kinase that acts as a cell-surface receptor for VEGFA, VEGFB and PGF, and plays an essential role in the development of embryonic vasculature, the regulation of angiogenesis, cell survival, cell migration, macrophage function, chemotaxis, and cancer cell invasion. Vascular endothelial growth factor receptor 1 is a protein that in humans is encoded by the FLT1 gene. Oncogene FLT belongs to the src gene family and is related to oncogene ROS. Like other members of this family, it shows tyrosine protein kinase activity that is important for the control of cell proliferation and differentiation. The sequence structure of the FLT gene resembles that of the FMS gene; hence, Yoshida et al. (1987) proposed the name FLT as an acronym for FMS-like tyrosine kinase. FLT1 has been shown to interact with PLCG1 and vascular endothelial growth factor B (VEGF-B).