title: Involvement of vasodilator-stimulated phosphoprotein in UDP-induced microglial actin aggregation via PKC- and Rho-dependent pathways.
abstract: Microglia are major immunocompetent cells in the central nervous system and retain highly dynamic motility. The processes which allow these cells to move, such as chemotaxis and phagocytosis, are considered part of their functions and are closely related to purinergic signaling. Previously, we reported that the activation of the P2Y(6) receptor by UDP stimulation in microglia evoked dynamic cell motility which enhanced their phagocytic capacity, as reported by Koizumi et al. (Nature 446(7139):1091-1095, 2007). These responses require actin cytoskeletal rearrangement, which is seen after UDP stimulation. However, the intracellular signaling pathway has not been defined. In this study, we found that UDP in rat primary microglia rapidly induced the transient phosphorylation at Ser157 of vasodilator-stimulated phosphoprotein (VASP). VASP, one of actin binding protein, accumulated at the plasma membrane where filamentous (F)-actin aggregated in a time-dependent manner. The phosphorylation of VASP was suppressed by inhibition of PKC. UDP-induced local actin aggregations were also abrogated by PKC inhibitors. The Rho inhibitor CT04 and the expression of p115-RGS, which suppresses G(12/13) signaling, attenuated UDP-induced phosphorylation of VASP and actin aggregation. These results indicate that PKC- and Rho-dependent phosphorylation of VASP is involved in UDP-induced actin aggregation of microglia.
authors.affiliation: Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi, Fukuoka, 812-8582, Japan.
authors.forename: Ayako
authors.initials: A
authors.lastname: Kataoka
authors.forename: Yui
authors.initials: Y
authors.lastname: Koga
authors.forename: Ayumi
authors.initials: A
authors.lastname: Uesugi
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Tozaki-Saitoh
authors.forename: Makoto
authors.initials: M
authors.lastname: Tsuda
authors.forename: Kazuhide
authors.initials: K
authors.lastname: Inoue