BINDING OF COLLAGEN-XIV WITH THE DERMATAN SULFATE SIDE-CHAIN OF DECORIN

As an approach to elucidate the role of collagen XIV, which is still u nclear, molecules exhibiting affinity for this collagen have been soug ht in connective tissue. Extracts from fetal bovine tendon were resolv ed by gel electrophoresis and electrophoretically transferred to nitro cellulose. The blot was overlaid with native collagen XIV and the coll agen XIV-binding molecules revealed by immunodecoration with a monoclo nal antitype XIV collagen antibody. This experimental approach allowed us to reveal in tendon extracts a diffuse band, with an apparent mole cular mass of approximately 100 kDa, that binds collagen XIV. This mol ecule was also found associated with the fractions containing partiall y purified type XIV collagen. This 100-kDa molecule was sensitive to c hondroitinase ABC and, after chondroitinase digestion, yielded a core protein of about 48 kDa. N-terminal sequence analysis of the proteogly can after blotting allowed us to identify it as decorin. By solid phas e assays we have studied this newly described association between deco rin and type XIV collagen and shown that it is a saturable process. In addition, preliminary determination of the domains of the two molecul es involved in the association has been performed. The possible role o f these interactions is discussed.