Yang Esther H, Rode Julia, Howlader Md Amran, Eckermann Marina, Santos Jobette T, Hernandez Armada Daniel, Zheng Ruixiang, Zou Chunxia, Cairo Christopher W
Alberta Glycomics Centre, Department of Chemistry, University of Alberta, Edmonton Alberta, Canada.
PLoS One. 2017 Oct 10;12(10):e0184378. doi: 10.1371/journal.pone.0184378. eCollection 2017.
Glycoprotein receptors are influenced by myriad intermolecular interactions at the cell surface. Specific glycan structures may interact with endogenous lectins that enforce or disrupt receptor-receptor interactions. Glycoproteins bound by multivalent lectins may form extended oligomers or lattices, altering the lateral mobility of the receptor and influencing its function through endocytosis or changes in activation. In this study, we have examined the interaction of Galectin-3 (Gal-3), a human lectin, with adhesion receptors. We measured the effect of recombinant Gal-3 added exogenously on the lateral mobility of the α5β1 integrin on HeLa cells. Using single-particle tracking (SPT) we detected increased lateral mobility of the integrin in the presence of Gal-3, while its truncated C-terminal domain (Gal-3C) showed only minor reductions in lateral mobility. Treatment of cells with Gal-3 increased β1-integrin mediated migration with no apparent changes in viability. In contrast, Gal-3C decreased both cell migration and viability. Fluorescence microscopy allowed us to confirm that exogenous Gal-3 resulted in reorganization of the integrin into larger clusters. We used a proteomics analysis to confirm that cells expressed endogenous Gal-3, and found that addition of competitive oligosaccharide ligands for the lectin altered the lateral mobility of the integrin. Together, our results are consistent with a Gal-3-integrin lattice model of binding and confirm that the lateral mobility of integrins is natively regulated, in part, by galectins.
糖蛋白受体受细胞表面无数分子间相互作用的影响。特定的聚糖结构可能与内源性凝集素相互作用，从而加强或破坏受体 - 受体相互作用。被多价凝集素结合的糖蛋白可能形成延伸的寡聚体或晶格，改变受体的侧向流动性，并通过内吞作用或激活变化影响其功能。在本研究中，我们研究了人凝集素半乳糖凝集素 -3（Gal-3）与黏附受体的相互作用。我们测量了外源添加的重组Gal-3对HeLa细胞上α5β1整合素侧向流动性的影响。使用单粒子追踪（SPT），我们检测到在Gal-3存在下整合素的侧向流动性增加，而其截短的C末端结构域（Gal-3C）仅显示侧向流动性有轻微降低。用Gal-3处理细胞增加了β1整合素介导的迁移，而细胞活力没有明显变化。相比之下，Gal-3C降低了细胞迁移和活力。荧光显微镜使我们能够确认外源Gal-3导致整合素重组为更大的簇。我们使用蛋白质组学分析来确认细胞表达内源性Gal-3，并发现添加该凝集素的竞争性寡糖配体改变了整合素的侧向流动性。总之，我们的结果与Gal-3 - 整合素结合晶格模型一致，并证实整合素的侧向流动性部分受半乳糖凝集素的天然调节。
