Signaling triggered by Thy-1 interaction with beta 3 integrin on astrocytes is an essential step towards unraveling neuronal Thy-1 function.
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.
Avalos
Ana María
AM
Program of Morphology, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, University of Chile.
Labra
Cecilia V
CV
Quest
Andrew F G
AF
Leyton
Lisette
L
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
D039661:Integrin beta3; D019030:Receptors, Vitronectin; D018800:Thy-1 Antigens; D020741:rho GTP-Binding Proteins