J. Biol. Chem., Vol. 261, Issue 26, 12079-12088, 09, 1986
Structure of proteoheparan sulfates from fibroblasts. Confluent and proliferating fibroblasts produce at least three types of proteoheparan sulfates with functionally different core proteins
L Coster, I Carlstedt, S Kendall, A Malmstrom, A Schmidtchen and LA Fransson
[3H]Leucine- and [35S]sulfate-labeled proteoheparan sulfates were isolated
from postconfluent or proliferating cultures of human skin fibroblasts.
Cell layers were solubilized by Triton X-100, and transferrin-binding
macromolecules were isolated by affinity chromatography. Proteoglycans with
no affinity for transferrin were purified by using ion-exchange and gel
permeation chromatography. Postconfluent cells synthesize a proteoheparan
sulfate of Mr 350,000 (as determined by gel permeation chromatography)
which has affinity for transferrin as well as for octyl-Sepharose. Its core
protein (Mr 180,000) consists of two disulfide-bonded polypeptides of Mr
90,000. This species was not detected in cultures of proliferating cells.
Proliferating and confluent cells also synthesize other forms of
proteoheparan sulfates (Mr 200,000-400,000) which have no affinity for
transferrin. However, most of them have affinity for octyl-Sepharose. The
core protein of proteoheparan sulfates made by proliferating cells has Mr
50,000. A smaller form (Mr 250,000) of this proteoglycan was solubilized by
Triton X-100, whereas a larger form (Mr 400,000) remained associated with
the pericellular matrix. A third type of proteoheparan sulfate (Mr 200,000)
without affinity for transferrin nor octyl-Sepharose was associated with
postconfluent cell layers but not with proliferating ones. Its core protein
has Mr 35,000. Heparan sulfate oligosaccharides (Mr 6,000 or higher) were
found in proliferating cells but not in postconfluent ones.