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Subunit: There are six type IV collagen isoforms, alpha 1(IV)-alpha 6(IV), each of which can form a triple helix structure with 2 other chains to generate type IV collagen network. The alpha 3(IV) chain forms a triple helical protomer with alpha 4(IV) and alpha 5(IV); this triple helical structure dimerizes through NC1-NC1 domain interactions such that the alpha 3(IV), alpha 4(IV) and alpha 5(IV) chains of one protomer connect with the alpha 5(IV), alpha 4(IV) and alpha 3(IV) chains of the opposite promoter, respectively. Interacts with COL4A3BP AND ITGB3. Associates with LAMB2 at the neuromuscular junction and in GBM (By similarity) Miscellaneous: The epitopes recognized by the Goodpasture autoantibodies are sequestered within the NC1 hexamer of the type IV collagen network
Tissue specificity: Alpha 3 and alpha 4 type IV collagens are colocalized and present in kidney, eye, basement membranes of lens capsule, cochlea, lung, skeletal muscle, aorta, synaptic fibers, fetal kidney and fetal lung. PubMed:8083201 reports similar levels of expression
Function: UniProtKB/Swiss-Prot Summary: CO4A3_HUMAN, Q01955 Function: 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 Function: Tumstatin, a cleavage fragment corresponding to the collagen alpha 3(IV) NC1 domain, possesses both anti-angiogenic and anti-tumor cell activity; these two anti-tumor properties may be regulated via RGD-independent ITGB3-mediated mechanisms
Similarity: Belongs to the type IV collagen family Contains 1 collagen IV NC1 (C-terminal non-collagenous) domain [IMAGE]
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