title: The F-BAR domain protein PACSIN2 associates with Rac1 and regulates cell spreading and migration.
abstract: The Rac1 GTPase controls cytoskeletal dynamics and is a key regulator of cell spreading and migration mediated by signaling through effector proteins, such as the PAK kinases and the Scar and WAVE proteins. We previously identified a series of regulatory proteins that associate with Rac1 through its hypervariable C-terminal domain, including the Rac1 activator β-Pix (also known as Rho guanine-nucleotide-exchange factor 7) and the membrane adapter caveolin-1. Here, we show that Rac1 associates, through its C-terminus, with the F-BAR domain protein PACSIN2, an inducer of membrane tubulation and a regulator of endocytosis. We show that Rac1 localizes with PACSIN2 at intracellular tubular structures and on early endosomes. Active Rac1 induces a loss of PACSIN2-positive tubular structures. By contrast, Rac1 inhibition results in an accumulation of PACSIN2-positive tubules. In addition, PACSIN2 appears to regulate Rac1 signaling; siRNA-mediated loss of PACSIN2 increases the levels of Rac1-GTP and promotes cell spreading and migration in a wound healing assay. Moreover, ectopic expression of PACSIN2 reduces Rac1-GTP levels in a fashion that is dependent on the PACSIN2-Rac1 interaction, on the membrane-tubulating capacity of PACSIN2 and on dynamin. These data identify the BAR-domain protein PACSIN2 as a Rac1 interactor that regulates Rac1-mediated cell spreading and migration.
authors.affiliation: Department of Molecular Cell Biology, Sanquin Research and Landsteiner Laboratory, Academic Medical Center, University of Amsterdam, 1066 CX Amsterdam, The Netherlands.
authors.forename: Bart-Jan
authors.initials: BJ
authors.lastname: de Kreuk
authors.forename: Micha
authors.initials: M
authors.lastname: Nethe
authors.forename: Mar
authors.initials: M
authors.lastname: Fernandez-Borja
authors.forename: Eloise C
authors.initials: EC
authors.lastname: Anthony
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Hensbergen
authors.forename: Andre M
authors.initials: AM
authors.lastname: Deelder
authors.forename: Markus
authors.initials: M
authors.lastname: Plomann
authors.forename: Peter L
authors.initials: PL
authors.lastname: Hordijk
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D019556:COS Cells; D002465:Cell Movement / Q000502:physiology*; D002522:Chlorocebus aethiops; D006367:HeLa Cells; D006801:Humans; D019169:Jurkat Cells; D008870:Microtubules / Q000378:metabolism; D054730:Protein Interaction Domains and Motifs; D015398:Signal Transduction; D014162:Transfection; D020830:rac1 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*; D018909:src Homology Domains
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C120714:PACSIN2 protein, human; D020830:rac1 GTP-Binding Protein