Department of Chemistry , Brandeis University , 415 South Street , Waltham , Massachusetts 02453 , United States.
Department of Biology , Brandeis University , 415 South Street , Waltham , Massachusetts 02454 , United States.
J Am Chem Soc. 2018 Mar 14;140(10):3505-3509. doi: 10.1021/jacs.7b13307. Epub 2018 Mar 1.
Despite the advancement of molecular imaging techniques, there is an unmet need for probes for direct imaging of membrane dynamics of live cells. Here we report a novel type of active (or enzyme responsive) probes to directly image membrane dynamics of live cells with high spatial and temporal resolution over extended time scales and areas. Because lipid rafts enrich cholesterols and GPI-anchored enzymes (e.g., ectophosphatases), we design probes that consist of an enzymatic trigger, a fluorophore, and a cholesterol that are affinitive to the cell membrane. Being water-soluble and as the substrate of ectophosphatase, these cell compatible probes preferentially and rapidly assemble in plasma membrane, exhibit strong fluorescence, work at micromolar concentrations, and easily achieve high resolution monitoring of nanoscale heterogeneity in membranes of live cells, the release of exosomes, and the membrane dynamics of live cells. This work provides a facile means to link membrane dynamics and heterogeneity to cellular processes for understanding the interactions between membranes and proteins.
尽管分子成像技术取得了进步，但仍需要开发探针来直接对活细胞的膜动力学进行成像。在这里，我们报告了一种新型的主动（或酶响应）探针，它可以在较长的时间和较大的区域内以高时空分辨率直接对活细胞的膜动力学进行成像。由于脂筏富含胆固醇和糖基磷脂酰肌醇锚定的酶（例如外磷酸酶），我们设计了由酶触发、荧光团和胆固醇组成的探针，这些探针与细胞膜具有亲和力。这些细胞相容性探针水溶性好，且作为外磷酸酶的底物，优先快速组装在质膜上，荧光强度强，工作浓度为微摩尔级，容易实现对活细胞膜中纳米级异质性、外泌体释放和活细胞膜动力学的高分辨率监测。这项工作为将膜动力学和异质性与细胞过程联系起来提供了一种简便的方法，以了解膜与蛋白质之间的相互作用。
