Arachidonic acid stimulates formation of a novel complex containing nucleolin and RhoA

Abstract

Arachidonic acid (AA) stimulates cell adhesion through a p38 mitogen activated protein kinase-mediated RhoA signaling pathway. Here we report that a proteomic screen following AA-treatment identified nucleolin, a multifunctional nucleolar protein, in a complex with the GTPase, RhoA, that also included the Rho kinase, ROCK. AA-stimulated cell adhesion was inhibited by expression of nucleolin-targeted shRNA and formation of the multiprotein complex was blocked by expression of dominant-negative RhoA. AA-treatment also induced ROCK-dependent serine phosphorylation of nucleolin and translocation of nucleolin from the nucleus to the cytoplasm, where it appeared to co-localize with RhoA. These data suggest the existence of a new signaling pathway through which the location and post-translational state of nucleolin are modulated. Structured summary Nucleolin physically interacts with RHOA by anti bait coimmunoprecipitation (View Interaction 1, 2) Nucleolin and RHOA colocalize by fluorescence microscopy (View interaction) ROCK physically interacts with RHOA by pull down (View interaction) ROCK physically interacts with HSP 90-beta , HSP70 , Nucleolin , Nebulin and RHOA by pull down (View interaction) Nucleolin physically interacts with ROCK2 by anti bait coimmunoprecipitation (View interaction) ROCK physically interacts with Nucleolin and RHOA by pull down (View interaction)