Collagen type IV (COL4) (COL4)

Collagen type IV is the fundamental structural protein of the basement membrane, providing the essential scaffold for capillary walls and pericapillary sheaths (UniProt: P02462). Unlike fibrillar collagens, Type IV collagen forms a flexible, multi-layered network through its C-terminal non-collagenous (NC1) domains and N-terminal 7S domains, which is critical for maintaining vascular integrity and regulating cell adhesion (PubMed: 12019209). It plays a vital role in the selective filtration barriers of the renal glomerulus and the blood-brain barrier, where its structural stability is paramount (PubMed: 25605800). In clinical pathology, Type IV collagen is the primary autoantigen in Goodpasture syndrome, where antibodies target the alpha-3 chain, leading to severe glomerulonephritis and pulmonary hemorrhage (StatPearls: NBK459291). Furthermore, its pathological accumulation is a hallmark of diabetic microangiopathy and various fibrotic conditions, contributing to tissue stiffening and organ dysfunction (PubMed: 15123941). While not a traditional signaling receptor, its degradation by matrix metalloproteinases and the release of its biologically active fragments, such as tumstatin, provide potent anti-angiogenic signals that are currently being explored for cancer and anti-fibrotic therapies (PubMed: 11739745).

Other names

Type IV collagenBasement membrane collagenCOL4ACapillary basement membrane collagenPericapillary collagen

Inhibition of collagen synthesis and deposition; enzymatic degradation of collagen fibers; modulation of angiogenesis through matrikine fragments; blockade of autoantibody binding in autoimmune disease.