Siglec-15 was recently reported to be an immunosuppressive molecule that is expressed by tumor-associated macrophages and upregulated in some solid tumors. Targeting Siglec-15 is a potential strategy for normalization cancer immunotherapy. Here, we identified the important post-translational modification, N-glycosylation of Siglec-15, which is regulated by glucose uptake. Using a series of glycosidase and glycosylation inhibitors, we demonstrated that Siglec-15 was completely N-glycosylated in vitro and in vivo. The precise glycosylation site was determined. N-glycosylation stabilized Siglec-15 by decreasing its lysosome-dependent degradation. Siglec-15 subcellular distribution detected by immunofluorescence indicated that N-glycosylation promoted Siglec-15 transportation to the cell membrane. The collective observations indicate that targeting the N-glycosylation of Siglec-15 may be an effective supplement to immunotherapy.

最近报道了Siglec-15是一种免疫抑制分子，它由肿瘤相关的巨噬细胞表达并在某些实体瘤中上调。靶向Siglec-15是规范化癌症免疫治疗的潜在策略。在这里，我们确定了重要的翻译后修饰，Siglec-15的N-糖基化，其受葡萄糖摄取的调节。使用一系列糖苷酶和糖基化抑制剂，我们证明了Siglec-15在体外和体内完全被N-糖基化。确定了精确的糖基化位点。N-糖基化通过减少其溶酶体依赖性降解来稳定Siglec-15。通过免疫荧光检测到的Siglec-15亚细胞分布表明N-糖基化促进了Siglec-15转运到细胞膜。集体观察表明，靶向Siglec-15的N-糖基化可能是免疫疗法的有效补充。