Anthrax Toxin Receptor 1 (ANTXR1) is a single-pass type I membrane protein that belongs to the ATR family. ANTXR1 contains one VWFA domain and binds PA through the VWA domain. ANTXR1 is highly expressed in tumor endothelial cells. ANTXR1 plays a role in cell attachment and migration. ANTXR1 interacts with extracellular matrix proteins and the actin cytoskeleton, it mediates adhesion of cells to type 1 collagen and gelatin, reorganization of the actin cytoskeleton and promotes cell spreading. It is also involved in the angiogenic response of cultured umbilical vein endothelial cells, up-regulated in cultured angiogenic umbilical vein endothelial cells. Defects in ANTXR1 are associated with susceptibility to hemangioma capillary infantile (HCI).