Avalos Ana María, Labra Cecilia V, Quest Andrew F G, Leyton Lisette
Program of Morphology, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, University of Chile.
Biol Res. 2002;35(2):231-8. doi: 10.4067/s0716-97602002000200015.
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.
Thy-1是哺乳动物中一种丰富的神经元糖蛋白。尽管如此普遍，但在缺乏明确配体的情况下，Thy-1的功能在很大程度上仍不清楚。本文将讨论最近描述的Thy-1与星形胶质细胞上的β3整合素相互作用的证据。Thy-1与β3整合素结合会触发星形胶质细胞中粘着斑蛋白的酪氨酸磷酸化，从而促进粘着斑形成、细胞附着和铺展。据报道，Thy-1通过触发神经元中的细胞反应来调节神经突生长。然而，我们的数据表明，Thy-1还可以启动促进相邻星形胶质细胞与下层表面粘附的信号事件。初步结果表明，Thy-1结合导致星形胶质细胞肌动蛋白细胞骨架中观察到的形态变化是由Rho家族的小GTP酶介导的。我们的研究结果表明，Thy-1以双峰方式发挥作用，作为神经元细胞上的受体和星形胶质细胞上β3整合素受体的配体。由于Thy-1与神经突生长的抑制有关，星形胶质细胞中的信号事件可能在这一过程中起重要作用。
