Department of Surgery, Beth Israel Deaconess Medical Center, National Center for Functional Glycomics, Harvard Medical School, Boston, MA 02215, USA; Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Department of Surgery, Beth Israel Deaconess Medical Center, National Center for Functional Glycomics, Harvard Medical School, Boston, MA 02215, USA.
Cell Chem Biol. 2023 Aug 17;30(8):893-905.e7. doi: 10.1016/j.chembiol.2023.06.013. Epub 2023 Jul 17.
Protein glycosylation influences cellular recognition and regulates protein interactions, but how glycosylation functions alongside other common posttranslational modifications (PTMs), like tyrosine sulfation (sTyr), is unclear. We produced a library of 53 chemoenzymatically synthesized glycosulfopeptides representing N-terminal domains of human and murine P-selectin glycoprotein ligand-1 (PSGL-1), varying in sTyr and O-glycosylation (structure and site). Using these, we identified key roles of PSGL-1 O-glycosylation and sTyr in controlling interactions with specific chemokines. Results demonstrate that sTyr positively affects CCL19 and CCL21 binding to PSGL-1 N terminus, whereas O-glycan branching and sialylation reduced binding. For murine PSGL-1, interference between PTMs is greater, attributed to proximity between the two PTMs. Using fluorescence polarization, we found sTyr is a positive determinant for some chemokines. We showed that synthetic sulfopeptides are potent in decreasing chemotaxis of human dendritic cells toward CCL19 and CCL21. Our results provide new research avenues into the interplay of PTMs regulating leukocyte/chemokine interactions.
蛋白质糖基化影响细胞识别并调节蛋白质相互作用，但糖基化如何与其他常见的翻译后修饰（PTM）协同作用，如酪氨酸硫酸化（sTyr），目前尚不清楚。我们合成了一个由 53 种化学酶合成的糖基化肽文库，代表人类和鼠类 P 选择素糖蛋白配体-1（PSGL-1）的 N 端结构域，这些结构域在 sTyr 和 O-糖基化（结构和位置）上存在差异。利用这些文库，我们确定了 PSGL-1 O-糖基化和 sTyr 在控制与特定趋化因子相互作用中的关键作用。结果表明，sTyr 可正向影响 CCL19 和 CCL21 与 PSGL-1 N 端的结合，而 O-聚糖分支和唾液酸化则降低了结合。对于鼠类 PSGL-1，两种 PTM 之间的干扰更大，这归因于两种 PTM 之间的接近。通过荧光偏振，我们发现 sTyr 是一些趋化因子的正向决定因素。我们还表明，合成的硫酸肽能有效降低人树突状细胞向 CCL19 和 CCL21 的趋化作用。我们的研究结果为研究 PTM 调节白细胞/趋化因子相互作用的相互作用提供了新的研究途径。
