Shape relaxations in a fluid supported membrane during hydrolysis by phospholipase A2

The behavior of a fluid supported membrane during hydrolysis by phospholipase A₂ is for the first time visualized by time-resolved fluorescence imaging. After a lag phase, hydrolysis proceeds from the boundary of existing holes and via nucleation of new holes. During subsequent hydrolysis, the shape of the membrane boundary is determined both by hydrolysis and by shape relaxations due to the action of line tension. This is manifested by the appearance of Rayleigh instabilities in membrane rims and by an effect analogous to domain coarsening in phase transitions in which membrane holes decay when they are within a certain distance from larger and expanding holes.