Ligand-induced growth and compaction of CD36 nanoclusters enriched in Fyn induces Fyn signaling
Ligand-induced growth and compaction of CD36 nanoclusters enriched in Fyn induces Fyn signaling
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DOI：
10.1242/jcs.188946
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发表时间：
2016-11-15
影响因子：
4
通讯作者：
Touret, Nicolas
中科院分区：
文献类型：
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作者：
Githaka, John Maringa;Vega, Anthony R.;Touret, Nicolas
纳米聚簇是膜相关蛋白的一种新兴组织原理。纳米聚类对受体信号的功能影响在很大程度上仍然未知。在这里，我们应用定量多通道高分辨率和超分辨率成像来分析内皮细胞表面受体CD36，其与多价配体（如抗血管生成因子血小板反应蛋白-1 (TSP-1)）结合时的聚类被认为对信号传导至关重要。我们发现大量未连接的CD36存在于纳米簇中，这些纳米簇不仅促进了TSP-1的结合，而且还富含下游效应因子Fyn。暴露于多价配体（TSP-1或抗CD36 IgM）会导致更大更密集的CD36簇激活Fyn。相反，阻止TSP-1增强CD36聚集的药理学扰动会取消Fyn的激活。在这两种情况下，CD36纳米簇上的Fyn富集没有可检测到的变化。这些观察结果揭示了受体基本组织成纳米簇的关键作用，这些纳米簇富含该受体的信号转导下游效应器，因此通过多价配体增强簇是必要的，并且足以激活下游效应器，而无需重新招募。
Nanoclustering is an emerging organizational principle for membrane-associated proteins. The functional consequences of nanoclustering for receptor signaling remain largely unknown. Here, we applied quantitative multi-channel high-and super-resolution imaging to analyze the endothelial cell surface receptor CD36, the clustering of which upon binding to multivalent ligands, such as the anti-angiogenic factor thrombospondin-1 (TSP-1), is thought to be crucial for signaling. We found that a substantial fraction of unligated CD36 exists in nanoclusters, which not only promote TSP-1 binding but are also enriched with the downstream effector Fyn. Exposure to multivalent ligands (TSP-1 or anti-CD36 IgM) that result in larger and denser CD36 clusters activates Fyn. Conversely, pharmacological perturbations that prevent the enhancement of CD36 clustering by TSP-1 abrogate Fyn activation. In both cases, there is no detectable change in Fyn enrichment at CD36 nanoclusters. These observations reveal a crucial role for the basal organization of a receptor into nanoclusters that are enriched with the signal-transducing downstream effectors of that receptor, such that enhancement of clustering by multivalent ligands is necessary and sufficient to activate the downstream effector without the need for its de novo recruitment.