title: CtBP1/BARS is an activator of phospholipase D1 necessary for agonist-induced macropinocytosis.
abstract: Vesicular trafficking such as macropinocytosis is a dynamic process that requires coordinated interactions between specialized proteins and lipids. A recent report suggests the involvement of CtBP1/BARS in epidermal growth factor (EGF)-induced macropinocytosis. Detailed mechanisms as to how lipid remodelling is regulated during macropinocytosis are still undefined. Here, we show that CtBP1/BARS is a physiological activator of PLD1 required in agonist-induced macropinocytosis. EGF-induced macropinocytosis was specifically blocked by 1-butanol but not by 2-butanol. In addition, stimulation of cells by serum or EGF resulted in the association of CtBP1/BARS with PLD1. Finally, CtBP1/BARS activated PLD1 in a synergistic manner with other PLD activators, including ADP-ribosylation factors as demonstrated by in vitro and intact cell systems. The present results shed light on the molecular basis of how the 'fission protein' CtBP1/BARS controls vesicular trafficking events including macropinocytosis.
authors.affiliation: Division of Biochemistry, Department of Molecular and Cellular Biology, Kobe University Graduate School of Medicine, Kobe, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Haga
authors.forename: Noriko
authors.initials: N
authors.lastname: Miwa
authors.forename: Saleem
authors.initials: S
authors.lastname: Jahangeer
authors.forename: Taro
authors.initials: T
authors.lastname: Okada
authors.forename: Shun-ichi
authors.initials: S
authors.lastname: Nakamura