ts371 KiMuSV-transformed rat kidney fibroblasts growing at the permissive temperature to allow the expression of a transforming p21 ras protein secrete a different pattern of chondroitin/dermatan sulfate proteoglycans than when growing at the non-permissive temperature. Transformed cells produce less versican and larger amounts of biglycan and decorin than their normal counterpart, and they do not secrete 35S-labeled PG-100. Western blot experiments showed the presence of PG-100 epitope, suggesting that the apparent effect of the oncoprotein is due to a reduced sulfation of the molecule. Transformed and non-transformed cells are similarly sensitive to the proteoglycan-induction effect of TGF-β. © 1994 Academic Press, Inc.