Receptor for TNFSF12/TWEAK. Weak inducer of apoptosis in some cell types. Promotes angiogenesis and the proliferation of endothelial cells. May modulate cellular adhesion to matrix proteins. Associates with TRAF1 and TRAF2, and probably also with TRAF3. Highly expressed in heart, placenta and kidney. Intermediate expression in lung, skeletal muscle and pancreas. By FGF1 and phorbol ester.