title: Amphidinolide H, a novel type of actin-stabilizing agent isolated from dinoflagellate.
abstract: The effect of novel cytotoxic marine macrolide, amphidinolide H (Amp-H), on actin dynamics was investigated in vitro. Amp-H attenuated actin depolymerization induced by diluting F-actin. This effect remained after washing out of unbound Amp-H by filtration. In the presence of either Amp-H or phalloidin, lag phase, which is the rate-limiting step of actin polymerization, was shortened. Phalloidin decreased the polymerization-rate whereas Amp-H did not. Meanwhile, the effects of both compounds were the same when barbed end of actin was capped by cytochalasin D. Quartz crystal microbalance system revealed interaction of Amp-H with G-actin and F-actin. Amp-H also enhanced the binding of phalloidin to F-actin. We concluded that Amp-H stabilizes actin in a different manner from that of phalloidin and serves as a novel pharmacological tool for analyzing actin-mediated cell function.
authors.affiliation: Department of Pharmaceutical Molecular Biology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578, Japan. synsaito@mail.pharm.tohoku.ac.jp
authors.forename: Shin-ya
authors.initials: SY
authors.lastname: Saito
authors.forename: Jue
authors.initials: J
authors.lastname: Feng
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kira
authors.forename: Jun'ichi
authors.initials: J
authors.lastname: Kobayashi
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Ohizumi
mesh_terms: D000199:Actins / Q000737:chemistry*; D000818:Animals; D019281:Dimerization; D004141:Dinoflagellida / Q000378:metabolism*; D018942:Macrolides / Q000737:chemistry* / Q000302:isolation & purification*; D046911:Macromolecular Substances; D011485:Protein Binding; D011489:Protein Denaturation; D000097442:Amphidinolides
chemical_list: D000199:Actins; D018942:Macrolides; D046911:Macromolecular Substances; C414664:amphidinolide H; D000097442:Amphidinolides