[Collagen type IV: major component of basement membranes. Current knowledge].

: The collagen family represents the most abundant protein in animals. Type IV collagen ([alpha 1 (IV)]2 alpha 2 (IV)) differs from the other types in several respects and particularly in its distribution, being strictly limited to the basement membranes. Alterations in the structure and functions of basement membranes are observed in a number of diseases, such as tumoral angiogenesis and diabetic nephropathy. This article reviews current structural and pathophysiological knowledge concerning type IV collagen.