title: Signaling triggered by Thy-1 interaction with beta 3 integrin on astrocytes is an essential step towards unraveling neuronal Thy-1 function.
abstract: Thy-1 is an abundant neuronal glycoprotein in mammals. Despite such prevalence, Thy-1 function remains largely obscure in the absence of a defined ligand. Recently described evidence that Thy-1 interacts with beta 3 integrin on astrocytes will be discussed. Thy-1 binding to beta 3 integrin triggers tyrosine phosphorylation of focal adhesion proteins in astrocytes, thereby promoting focal adhesion formation, cell attachment and spreading. Thy-1 has been reported to modulate neurite outgrowth by triggering a cellular response in neurons. However, our data indicate that Thy-1 can also initiate signaling events that promote adhesion of adjacent astrocytes to the underlying surface. Preliminary results suggest that morphological changes observed in the actin cytoskeleton of astrocytes as a consequence of Thy-1 binding is mediated by small GTPases from the Rho family. Our findings argue that Thy-1 functions in a bimodal fashion, as a receptor on neuronal cells and as a ligand for beta 3 integrin receptor on astrocytes. Since Thy-1 is implicated in the inhibition of neurite outgrowth, signaling events in astrocytes are likely to play an important role in this process.
authors.affiliation: Program of Morphology, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, University of Chile.
authors.forename: Ana María
authors.initials: AM
authors.lastname: Avalos
authors.forename: Cecilia V
authors.initials: CV
authors.lastname: Labra
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 / Q000502:physiology*; D006801:Humans; D039661:Integrin beta3 / Q000502:physiology*; D009474:Neurons / Q000502:physiology*; D019030:Receptors, Vitronectin / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D018800:Thy-1 Antigens / Q000502:physiology*; D020741:rho GTP-Binding Proteins / Q000502:physiology
chemical_list: D039661:Integrin beta3; D019030:Receptors, Vitronectin; D018800:Thy-1 Antigens; D020741:rho GTP-Binding Proteins