title: Direct interaction of Cucurbitacin E isolated from Alsomitra macrocarpa to actin filament.
abstract: A methanol extract of Alsomitra macrocarpa leaves and branches induced a marked alteration of cell morphology in a human stellate cell line (LX-2). Similar morphologic alterations were observed in several other cell lines. Active compound was purified from the extract and determined to be cucurbitacin E (Cuc E). It has been known that Cuc E causes marked disruption of the actin cytoskeleton, supporting our observation, but how Cuc E altered the actin cytoskeleton has not been elucidated. By using the standard fluorescence assay using copolymerization and depolymerization of native and pyrene labelled actin, this study revealed that Cuc E interacted directly with actin consequently stabilizing the polymerized actin. When NIH-3T3 cells exogenously expressing YFP-labeled actin were treated with Cuc E, firstly the aggregation of globular actin and secondly the aggregation of actin including disrupted fibrous actin in the cells was observed.
authors.affiliation: Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Momma
authors.forename: Yuko
authors.initials: Y
authors.lastname: Masuzawa
authors.forename: Naomi
authors.initials: N
authors.lastname: Nakai
authors.forename: Moeko
authors.initials: M
authors.lastname: Chujo
authors.forename: Akira
authors.initials: A
authors.lastname: Murakami
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Kioka
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Kiyama
authors.forename: Toru
authors.initials: T
authors.lastname: Akita
authors.forename: Masaya
authors.initials: M
authors.lastname: Nagao