ABSTRACT
Heparin at concentrations below 100 micrograms/ml stimulated anchorage-independent growth of NRK 49F (normal rat kidney fibroblasts, American type culture collection) rat fibroblasts at suboptimal cytokine concentrations but inhibited it at higher heparin concentrations regardless of the cytokine concentration. Heparin did not stimulate growth above that seen at optimal cytokine concentrations, suggesting that it alters the cellular response to the cytokines. These data suggest natural protein-glycosaminoglycan interactions play a role in modulating or mediating the actions of transforming cytokines and suggest they may play a role in acquisition of the transformed phenotype.
Subject(s)
Fibroblasts/cytology , Heparin/pharmacology , Agar , Animals , Cell Adhesion , Cell Division/drug effects , Epidermal Growth Factor/pharmacology , Fibroblasts/drug effects , Platelet-Derived Growth Factor/pharmacology , Rats , Transforming Growth Factor beta/pharmacologyABSTRACT
We report the identification of a sperm surface protein which binds tightly to heparin. The protein was isolated by affinity chromatography on heparin agarose, and its affinity for heparin was confirmed by electrophoresis in the presence of heparin under non-denaturing conditions. The protein consists of a single polypeptide chain with a molecular weight of 45,000, as determined by electrophoresis under denaturing conditions. The protein may bind glycosaminoglycans in vivo and play a part in initiating the capacitation/acrosome reaction.
