Plexin Domain-Containing Protein 1 (PLXDC1) is a single-pass type I membrane protein that belongs to the plexin family. Secreted PLXDC1 is localized predominantly at the tight junctions of vascular endothelial cells and to a lesser extent at the luminal surface of vascular endothelial cells. PLXDC1 is expressed in fibrovascular membrane with increased expression in individuals with proliferative diabetic retinopathy. It can detect in endothelial cells from colorectal cancer, and in endothelial cells from primary cancers of the lung, liver, pancreas, breast and brain. PLXDC1 interacts with NID1 and may also interact with CTTN. It plays a important role in endothelial cell capillary morphogenesis, the proliferation and maintenance of neovascular endothelial cells in the formation of fibrovascular membranes (FVMs).