Binding of the polycation DEAE-dextran to the cell surface of HA-1 CHO cells caused a marked increase in45Ca2+exchange influx. The effect was fairly selective for Ca2+, undirectional (efflux was not increased) and was rapidly reversed by treatment with polyanion dextran sulfate.45Ca2+influx could not be stimulated by treatment with multivalent lectins or fibronectin. In addition to stimulating45Ca2+flux, DEAE-dextran inhibited the capping of concanavalin-A acceptor proteins. Inhibition of capping occurred over the same DEAE-dextran concentration range (20-200 μg/ml) which stimulated45Ca2+uptake, possibly implicating increased cellular [Ca2+] in the inhibition of concanavalin A acceptor protein capping in this cell type. The profound effect of DEAE-dextran on cellular Ca2+uptake and the rapid reversal of the effect by dextran sulfate might make the polycation a useful agent for the induction of transient increases in cellular [Ca2+]. © 1986.
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