Type IV collagen is the major structural component of glomerular basement membranes (GBM), forming a ‘chicken-wire’ meshwork together with laminins, proteoglycans and entactin/nidogen. ; Arresten, comprising the C-terminal NC1 domain, inhibits angiogenesis and tumor formation. The C-terminal half is found to possess the anti-angiogenic activity. Specifically inhibits endothelial cell proliferation, migration and tube formation.