In living organisms, Ca 2+ signalling is central to cell physi-ology. The Ca 2+ chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N¢,N¢-tetraaceticacid (BAPTA) hasbeenwidelyusedas a probe to test the role of calcium in a large variety of cell functions. Here we show that inmost cell types BAPTAhas a potent actin and microtubule depolymerizing activity and that this activity is completely independent of Ca 2+ chela-tion. Thus, the depolymerizing effect of BAPTA is sharedby a derivative (D-BAPTA) showing a dramatically reduced calcium chelating activity
