title: Direct Thy-1/alphaVbeta3 integrin interaction mediates neuron to astrocyte communication.
abstract: Thy-1 is an abundant neuronal glycoprotein of poorly defined function. We recently provided evidence indicating that Thy-1 clusters a beta3-containing integrin in astrocytes to induce tyrosine phosphorylation, RhoA activation and the formation of focal adhesions and stress fibers. To date, the alpha subunit partner of beta3 integrin in DI TNC1 astrocytes is unknown. Similarly, the ability of neuronal, membrane-bound Thy-1 to trigger astrocyte signaling via integrin engagement remains speculation. Here, evidence that alphav forms an alphavbeta3 heterodimer in DI TNC1 astrocytes was obtained. In neuron-astrocyte association assays, the presence of either anti-alphav or anti-beta3 integrin antibodies reduced cell-cell interaction demonstrating the requirement of both integrin subunits for this association. Moreover, anti-Thy-1 antibodies blocked stimulation of astrocytes by neurons but not the binding of these two cell types. Thus, neuron-astrocyte association involved binding between molecular components in addition to the Thy-1-integrin; however, the signaling events leading to focal adhesion formation in astrocytes depended exclusively on the latter interaction. Additionally, wild-type (RLD) but not mutated (RLE) Thy-1 was shown to directly interact with alphavbeta3 integrin by Surface Plasmon Resonance analysis. This interaction was promoted by divalent cations and was species-independent. Together, these results demonstrate that the alphavbeta3 integrin heterodimer interacts directly with Thy-1 present on neuronal cells to stimulate astrocytes.
authors.affiliation: Program of Cell and Molecular Biology, FONDAP, Center for Molecular Studies of the Cell (CEMC), Institute of Biomedical Sciences (ICBM), Facultad de Medicina, Universidad de Chile, Santiago, Chile.
authors.forename: Tamara
authors.initials: T
authors.lastname: Hermosilla
authors.forename: Daniel
authors.initials: D
authors.lastname: Muñoz
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Herrera-Molina
authors.forename: Alejandra
authors.initials: A
authors.lastname: Valdivia
authors.forename: Nicolás
authors.initials: N
authors.lastname: Muñoz
authors.forename: Sang-Uk
authors.initials: SU
authors.lastname: Nham
authors.forename: Pascal
authors.initials: P
authors.lastname: Schneider
authors.forename: Keith
authors.initials: K
authors.lastname: Burridge
authors.forename: Andrew F G
authors.initials: AF
authors.lastname: Quest
authors.forename: Lisette
authors.initials: L
authors.lastname: Leyton
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000502:physiology*; D015153:Blotting, Western; D002448:Cell Adhesion / Q000502:physiology; D002450:Cell Communication; D002478:Cells, Cultured; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D047468:Immunoprecipitation; D039302:Integrin alphaVbeta3 / Q000378:metabolism*; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D051381:Rats; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D020349:Surface Plasmon Resonance; D018800:Thy-1 Antigens / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
chemical_list: D039302:Integrin alphaVbeta3; D011994:Recombinant Proteins; D018800:Thy-1 Antigens; D020742:rhoA GTP-Binding Protein