Endosomal acidic pH-induced conformational changes of a cytosol-penetrating antibody mediate endosomal escape
Endosomal acidic pH-induced conformational changes of a cytosol-penetrating antibody mediate endosomal escape
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DOI：
10.1016/j.jconrel.2016.05.066
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发表时间：
2016-08-10
影响因子：
10.8
通讯作者：
Kim, Yong-Sung
中科院分区：
文献类型：
--
作者：
Kim, Ji-Sun;Choi, Dong-Ki;Kim, Yong-Sung
内吞作用后的内体逃逸是基于蛋白质的药物在细胞的胞质溶胶中显示其作用的关键步骤。然而，通过内吞作用内化到细胞中的抗体由于不能从溶酶体逃逸而不能到达胞质溶胶。在这里，我们报告了一个独特的内体逃逸机制的IgG格式TMab4抗体，它可以达到活细胞的胞质溶胶后内化。TMab4从其细胞表面受体硫酸乙酰肝素蛋白聚糖的激活乙酰肝素酶在酸化的早期内体的解离，然后响应于酸化的内体pH值的TMab4的内体逃逸基序的局部结构变化是至关重要的膜孔的形成，通过该膜孔TMab4逃逸到胞质溶胶。内体逃逸的结构决定子的鉴定使我们产生了具有类似于3倍提高的内体逃逸效率的TMab 4变体。我们对胞质穿透抗体内体逃逸机制的发现及其改进将建立一种平台技术，使全长IgG抗体能够直接靶向胞质蛋白。(C)2016年爱思唯尔B。版权所有© 2016
Endosomal escape after endocytosis is a critical step for protein-based agents to exhibit their effects in the cytosol of cells. However, antibodies internalized into cells by endocytosis cannot reach the cytosol due to their inability to escape fromendosomes. Here, we report a unique endosomal escape mechanism of the IgG-format TMab4 anti-body, which can reach the cytosol of living cells after internalization. Dissociation of TMab4 from its cell surface receptor heparan sulfate proteoglycan by activated heparanase in acidified early endosomes and then local structural changes of the endosomal escape motif ofTMab4 in response to the acidified endosomal pH were critical for the formation of membrane pores through which TMab4 escaped into the cytosol. Identification of structural determinants of endosomal escape led us to generate a TMab4 variant with similar to 3-fold improved endosomal escape efficiency. Our finding of the endosomal escape mechanismof the cytosol-penetrating antibody and its improvement will establish a platform technology that enables a full-length IgG antibody to directly target cytosolic proteins. (C) 2016 Elsevier B. V. All rights reserved.