Jamal Basem T, Nita-Lazar Mihai, Gao Zhennan, Amin Bakr, Walker Janice, Kukuruzinska Maria A
Department of Molecular and Cell Biology, Boston University Medical Center, Boston, MA, USA.
Cell Health Cytoskelet. 2009 Sep 16;2009(1):67-80. doi: 10.2147/chc.s5965.
N-glycosylation of E-cadherin has been shown to inhibit cell-cell adhesion. Specifically, our recent studies have provided evidence that the reduction of E-cadherin N-glycosylation promoted the recruitment of stabilizing components, vinculin and serine/threonine protein phosphatase 2A (PP2A), to adherens junctions (AJs) and enhanced the association of AJs with the actin cytoskeleton. Here, we examined the details of how N-glycosylation of E-cadherin affected the molecular organization of AJs and their cytoskeletal interactions. Using the hypoglycosylated E-cadherin variant, V13, we show that V13/β-catenin complexes preferentially interacted with PP2A and with the microtubule motor protein dynein. This correlated with dephosphorylation of the microtubule-associated protein tau, suggesting that increased association of PP2A with V13-containing AJs promoted their tethering to microtubules. On the other hand V13/γ-catenin complexes associated more with vinculin, suggesting that they mediated the interaction of AJs with the actin cytoskeleton. N-glycosylation driven changes in the molecular organization of AJs were physiologically significant because transfection of V13 into A253 cancer cells, lacking both mature AJs and tight junctions (TJs), promoted the formation of stable AJs and enhanced the function of TJs to a greater extent than wild-type E-cadherin. These studies provide the first mechanistic insights into how N-glycosylation of E-cadherin drives changes in AJ composition through the assembly of distinct β-catenin- and γ-catenin-containing scaffolds that impact the interaction with different cytoskeletal components.
E-钙黏蛋白的N-糖基化已被证明会抑制细胞间黏附。具体而言,我们最近的研究提供了证据表明,E-钙黏蛋白N-糖基化的减少促进了稳定成分纽蛋白和丝氨酸/苏氨酸蛋白磷酸酶2A(PP2A)向黏附连接(AJs)的募集,并增强了AJs与肌动蛋白细胞骨架的关联。在此,我们研究了E-钙黏蛋白的N-糖基化如何影响AJs的分子组织及其细胞骨架相互作用的细节。使用低糖基化的E-钙黏蛋白变体V13,我们发现V13/β-连环蛋白复合物优先与PP2A以及微管运动蛋白动力蛋白相互作用。这与微管相关蛋白tau的去磷酸化相关,表明PP2A与含V13的AJs的增加关联促进了它们与微管的连接。另一方面,V13/γ-连环蛋白复合物与纽蛋白的关联更多,表明它们介导了AJs与肌动蛋白细胞骨架的相互作用。AJs分子组织中由N-糖基化驱动的变化具有生理意义,因为将V13转染到既缺乏成熟AJs又缺乏紧密连接(TJs)的A253癌细胞中,比野生型E-钙黏蛋白更能促进稳定AJs的形成并增强TJs的功能。这些研究首次提供了关于E-钙黏蛋白的N-糖基化如何通过组装不同的含β-连环蛋白和γ-连环蛋白的支架来驱动AJ组成变化的机制见解,这些支架会影响与不同细胞骨架成分的相互作用。