Activation of phospholipase A2 by Hsp70 in vitro

► Here we demonstrate the activation of a secretory phospholipase A2 by Hsp70 in vitro. ► This supports the mechanism of phospholipase A2 regulation by oligomerization-amyloid formation acting as an on-off switch for enzyme activity. ► The activation reported here requires ATP and Mg2+, thus demonstrating that catalytic activity of HSp70 is involved. ► This mechanism may well be involved in the activation of other membrane associated enzymes, such as sphingomyelinase.