<protein> A dumbbell shaped 150 kD sulphated glycoprotein that is found in all basement membranes. It binds to laminin, forming a very stable 1:1 complex (KD = 10nM) and almost all laminin preparations contain entactin. The N terminal globular domain can self aggregate, whilst the C terminal globular domain binds to the short arm of laminin and to collagen IV. The connecting rod has 5-6 EGF type cysteine rich repeats, one of which has an RGD sequence for cellular interaction.