Binds to TGF-beta. Could be involved in capturing and retaining TGF-beta for presentation to the signaling receptors (By similarity). Interacts with DYNLT4. Exists both as a membrane-bound form and as soluble form in serum and in the extracellular matrix. Extensively modified by glycosaminoglycan (GAG), either chondroitin sulfate or heparan sulfate depending upon the tissue of origin.