文献类型：期刊文献

英文题名：Discovery of the cell-penetrating function of A2 domain derived from LTA subunit of Escherichia coli heat-labile enterotoxin

作者：Liu, Di[1,2];Guo, Hua[1,2];Zheng, Wenyun[3];Zhang, Na[1,2];Wang, Tianwen[1,2];Wang, Ping[1,2];Ma, Xingyuan[1,2]

机构：[1]E China Univ Sci & Technol, Sch Biotechnol, Shanghai 200237, Peoples R China;[2]E China Univ Sci & Technol, State Key Lab Bioreactor Engn, Shanghai 200237, Peoples R China;[3]E China Univ Sci & Technol, Sch Pharm, Shanghai Key Lab New Drug Design, Shanghai 200237, Peoples R China

年份：2016

卷号：100

期号：11

起止页码：5079

外文期刊名：APPLIED MICROBIOLOGY AND BIOTECHNOLOGY

收录：;EI(收录号：20161102094280);WOS:【SCI-EXPANDED(收录号:WOS:000376255200031)】；

基金：This research was supported by the National Natural Science Foundation (30873190, 31300660), Science and Technology Innovation Action Plan of Shanghai (14431904300), Shanghai Pujiang Program (13PJD012), and a Foundation for Young Teacher from Education Ministry of China (20120074120027) and partially supported by Open Funding Project of the State Key Laboratory of Bioreactor Engineering.

语种：英文

外文关键词：Heat-labile enterotoxin (LT); A2 domain; Cell-penetrating; Multi-endocytosis pathway; Drugs delivery

摘要：Heat-labile enterotoxin (LT) is a protein toxin produced by enterotoxigenic Escherichia coli (ETEC). As a bacterial toxin, LT holotoxin can enter intestinal epithelial cells and cause diarrhea. In addition, LT is also a powerful mucosal adjuvant capable of enhancing the strong immune responses to co-administered antigens. However, the LT immunological mechanism is still not clear in some aspects, especially with the respect to how the LTA subunit functions alone. Here, we discovered that the A(2) domain of LTA could carry a fluorescent protein into cells, whose function is similar to a cell-penetrating peptide. The transmembrane-transporting ability of the A(2) domain is non-specific in its cell-penetrating function, which was shown through testing with different cell types. Moreover, the LTA(2) fusion protein penetrated a fluorescently labeled cell membrane that identified LTA(2) internalization through membrane transport pathways, and showed it finally localized in the endoplasmic reticulum. Furthermore, low-temperature stress and pharmacological agent treatments showed that the LTA(2) internalization route is a temperature-dependent process involving the clathrin-mediated endocytosis and the macropinocytosis pathways. These results could explain the internalization of the LTA subunit alone without the LTB pentamer, contributing to a better understanding of LTA working as a mucosal adjuvant; they also suggest that the A(2) domain could be used as a novel transport vehicle for research and treatment of disease.