GPI-Anchored Ligand-BioID2-Tagging System Identifies Galectin-1 Mediating Zika Virus Entry Gao et al

Identification of host factors facilitating pathogen entry is critical for preventing infectious diseases. Here, we report a tagging system consisting of a viral receptor-binding protein (RBP) linked to BioID2, which is expressed on the cell surface via a GPI anchor. Using VSV or Zika virus (ZIKV) RBP, the system (BioID2- RBP(V)-GPI; BioID2-RBP(Z)-GPI) faithfully identifies LDLR and AXL, the receptors of VSV and ZIKV, respectively. Being GPI-anchored is essential for the probe to function properly. Furthermore, BioID2-RBP(Z)-GPI expressed in human neuronal progenitor cells identifies galectin-1 on cell surface pivotal for ZIKV entry. This conclusion is further supported by antibody blocking and galectin-1 silencing in A549 and mouse neural cells. Importantly, Lgas1-/- mice are significantly more resistant to ZIKV infection than Lgas1+/+ littermates are, having significantly lower virus titers and fewer pathologies in various organs. This tagging system may have broad applications for identifying protein-protein interactions on the cell surface.

鉴定可促进病原体入侵的宿主因子，对于感染性疾病的防控至关重要。本研究报道了一种标记系统：该系统由连接至生物素连接酶（BioID2）的病毒受体结合蛋白（RBP）构成，并通过糖基磷脂酰肌醇锚（GPI锚）定位于细胞表面。利用水疱性口炎病毒（VSV）或寨卡病毒（ZIKV）的RBP，该系统（BioID2-RBP(V)-GPI、BioID2-RBP(Z)-GPI）可精准识别VSV的受体低密度脂蛋白受体（LDLR）以及ZIKV的受体AXL。GPI锚定对于该探针的正常功能不可或缺。此外，在人类神经祖细胞中表达的BioID2-RBP(Z)-GPI，可识别细胞表面的半乳糖凝集素1（galectin-1），该蛋白对ZIKV入侵至关重要。这一结论通过在A549细胞与小鼠神经细胞中开展的抗体阻断实验及半乳糖凝集素1基因沉默实验得到了进一步验证。尤为重要的是，与Lgas1野生型同窝小鼠（Lgas1+/+）相比，Lgas1基因敲除小鼠（Lgas1-/-）对ZIKV感染的抵抗力显著增强，其体内病毒滴度显著降低，且多器官的病理损伤也明显减轻。该标记系统在鉴定细胞表面蛋白质间相互作用的研究中具有广阔的应用前景。