Rat hepatocyte hyaluronan/glycosaminoglycan binding proteins: evidence for distinct divalent cation-independent and divalent cation-dependent activities.
We have previously shown (Biochemistry, 29, 10425, 1990) that hepatocytes contain intracellular specific binding sites for hyaluronan (HA). Although HA-binding activity is not dependent on divalent cations, it is increased in the presence of Ca+2. Here we report that a novel photoaffinity HA derivative (ASD-HA) crosslinks specifically to different proteins in permeable cells in the presence or absence of Ca+2. With Ca+2 present, two proteins of approximately 24 kD and 43 kD were labeled. Additionally, a broad zone of specific crosslinking was observed in the region of 40-100 kD. However, in the presence of the chelator EGTA this zone was absent and the 24 and 43 kD proteins were also not cross-linked to the HA photoaffinity derivative. In the absence of Ca+2, only a 54 kD protein was specifically labeled. The results indicate that different intracellular hepatocyte proteins are responsible for the Ca+2-independent and the Ca+2-dependent binding of HA.
D000818:Animals; D002122:Calcium Chloride / Q000494:pharmacology; D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002463:Cell Membrane Permeability; D002478:Cells, Cultured; D003432:Cross-Linking Reagents; D004533:Egtazic Acid / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D006025:Glycosaminoglycans / Q000378:metabolism*; D018960:Hyaluronan Receptors; D006820:Hyaluronic Acid / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000378:metabolism*; D008297:Male; D008970:Molecular Weight; D051381:Rats; D017207:Rats, Sprague-Dawley
D002352:Carrier Proteins; D003432:Cross-Linking Reagents; D006025:Glycosaminoglycans; D018960:Hyaluronan Receptors; D004533:Egtazic Acid; D006820:Hyaluronic Acid; D002122:Calcium Chloride