Rat hepatocyte hyaluronan/glycosaminoglycan binding proteins: evidence for distinct divalent cation-independent and divalent cation-dependent activities

• Published in: Biochemical and biophysical research communications Vol. 189; no. 3; p. 1591
• Main Authors: Frost, S J, Kindberg, G M, Oka, J A, Weigel, P H
• Format: Journal Article
• Language: English
• Published: United States 30-12-1992
• Subjects: Animals; Calcium Chloride - pharmacology; Carrier Proteins - isolation & purification; Carrier Proteins - metabolism; Cell Membrane Permeability; Cells, Cultured; Cross-Linking Reagents; Egtazic Acid - pharmacology; Electrophoresis, Polyacrylamide Gel; Glycosaminoglycans - metabolism; Hyaluronan Receptors; Hyaluronic Acid - metabolism; Kinetics; Liver - metabolism; Male; Molecular Weight; Rats; Rats, Sprague-Dawley
• ISSN: 0006-291X
• DOI: 10.1016/0006-291X(92)90258-M

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.