Jasplakinolide(Jaspamide), a naturally occurring cyclic peptide from marine sponges, is a potent inducer of actin polymerization.Jasplakinolide exhibits antifungal and antitumor activity and stabilizes pre-existing actin filaments. Jasplakinolide competitively binds to F-actin with the ghost pen cyclic peptide and has a Kd value of 15 nM for F-actin.