Incubation of hen erythrocytes with Ca2+ and the bivalent-cation ionophore A23187 induced slight cell fusion in 1 h at 37 degrees C, and extensive fusion during a subsequent 15 min at 47 degrees C. Redistributions of intramembranous particles were observed, possibly involving interactions between Ca2+ and phospholipids, which are discussed in relation to molecular mechanimss of cell fusion.
