J. Biol. Chem., Vol. 259, Issue 15, 9440-9446, Aug, 1984
Endogenous hyaluronate-cell surface interactions in 3T3 and simian virus-transformed 3T3 cells
RL Goldberg, JD Seidman, G Chi-Rosso and BP Toole
3T3 cells have a large, pericellular coat which contains 30 times more
hyaluronate than the amount of cell surface hyaluronate associated with
simian virus 40-transformed 3T3 (SV-3T3) cells. On the other hand, SV- 3T3
cells have high affinity binding sites for exogenously added hyaluronate,
whereas 3T3 cells have much lower affinity sites. Removal of cell surface
hyaluronate from SV-3T3 cells by treatment with hyaluronidase caused a
reproducible increase in their maximum binding capacity for exogenous
hyaluronate but no significant change in binding affinity or specificity.
For 3T3 cells, however, the maximum amount of binding decreased and the
affinity of binding increased after hyaluronidase treatment. When
endogenous cell surface hyaluronate was labeled metabolically and then the
cells incubated in the presence of exogenous unlabeled hyaluronate, the
labeled cell surface hyaluronate was quantitatively displaced from the
SV-3T3 cells but was not displaced from the 3T3 cells. Chondroitin sulfate
and heparin did not displace cell surface hyaluronate from either cell
type. Membranes isolated from SV-3T3 cells bound hyaluronate specifically
and with high affinity, whereas membranes from 3T3 cells did not
consistently bind a significant amount of hyaluronate. We conclude from
these studies that the retention of endogenous hyaluronate on the surface
of SV-3T3 cells is mediated by binding sites similar to those detected by
the addition of exogenous hyaluronate, and the mechanism of retention of
endogenous hyaluronate on the surface of 3T3 cells differs from SV-3T3
cells.
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