May play a role in CNS development by interacting with growth factors implicated in motor neuron differentiation and survival. May play a role in capillary formation and maintenance during angiogenesis. Modulates BMP activity by affecting its processing and delivery to the cell surface. Interacts with BMP4 and BMP7. Expressed in pancreas, kidney, skeletal muscle, lung, placenta, brain, heart, spleen, liver and small intestine. Expressed in blood vessels (at protein level). N-glycosylated.