Actin disruption is used to study cell functions in vitro (e.g., migration, endocytosis) and in vivo (e.g., tumor cell invasion). Latrunculin A is a bioactive 2-thiazolidinone macrolide derived from sponges that sequesters G-actin and prevents F-actin assembly. It binds monomeric actin with 1:1 stoichiometry and can be used to block actin polymerization both in vitro (Kd = 0.2 μM) and in cells (0.5 μM, 30 min).[1],[2],[3] Latrunculin A (1-10 μM) causes depolymerization of tumor cell cytoskeleton within ten minutes.[4] Overnight treatment of cells with latrunculin A (10 μM) strongly suppresses actin synthesis.[5] Prolonged cell treatment blocks dexamethasone-induced changes in actin cytoskeleton with no effect on cell viability.[6]

References
[1]. Coué, M., Brenner, S.L., Spector, I., et al. Inhibition of actin polymerization by latrunculin A. FEBS Letters 213(2), 316-318 (1987).
[2]. Yarmola, E.G., Somasundaram, T., Boring, T.A., et al. Actin-latrunculin A structure and function. The Journal of Biological Chemisty 275(36), 28120-28127 (2000).
[3]. Loubéry, S., Wilhelm, C., Hurbain, I., et al. Different microtubule motors move early and late endocytic compartments. Traffic 9, 492-509 (2008).
[4]. Hayot, C., Debeir, O., Van Ham, P., et al. Characterization of the activities of actin-affecting drugs on tumor cell migration. Toxicology and Applied Pharmacology 211, 30-40 (2006).
[5]. Lyubimova, A., Bershadsky, A.D., and Ben-Ze'ev, A. Autoregulation of actin synthesis requires the 3'-UTR of actin mRNA and protects cells from actin overproduction. Journal of Cellular Biochemistry 76, 1-12 (1999).
[6]. Liu, X., Wu, Z., Sheibani, N., et al. Low dose latrunculin-A inhibits dexamethasone-induced changes in the actin cytoskeleton and alters extracellular matrix protein expression in cultured human trabecular meshwork cells. Experimental Eye Research 77, 181-188 (2003).