SELECTIVE INACTIVITY OF TGF-BETA DECORIN COMPLEXES

Previous studies had shown that binding of TGF-beta to the small prote oglycan decorin results in its inactivation. Indeed, in osteosarcoma c ells the addition of decorin prevented the TGF-beta 1-mediated up-regu lation of biglycan synthesis. However, the down-regulation of proteogl ycan-100 remained unaltered. Even in the presence of a 100,000-fold mo lar excess of decorin, TGF-beta 1 was fully active in U937 monocytes w ith respect to the inhibition of cell proliferation. There was no inhi bition of the TGF-beta-mediated stimulation of the retraction of fibro blast-populated collagen lattices. Thus, the formation of TGF-beta/dec orin complexes leads to the neutralization of distinct effects only.