Zhang X, Candas M, Griko N B, Rose-Young L, Bulla L A
Biological Targets, Inc., Dallas, TX 75235, USA.
Cell Death Differ. 2005 Nov;12(11):1407-16. doi: 10.1038/sj.cdd.4401675.
The specific role of cadherin receptors in cytotoxicity involving Cry toxins of Bacillus thuringiensis and their interactions with cell membrane has not been defined. To elucidate the involvement of toxin-membrane and toxin-receptor interactions in cytotoxicity, we established a cell-based system utilizing High Five insect cells stably expressing BT-R1, the cadherin receptor for Cry1Ab toxin. Cry1Ab toxin is incorporated into cell membrane in both oligomeric and monomeric form. Monomeric toxin binds specifically to BT-R1 whereas incorporation of oligomeric toxin is nonspecific and lipid dependent. Toxin oligomers in the cell membrane do not produce lytic pores and do not kill insect cells. Rather, cell death correlates with binding of the Cry1Ab toxin monomer to BT-R1, which apparently activates a Mg2+-dependent cellular signaling pathway.
钙黏蛋白受体在苏云金芽孢杆菌Cry毒素介导的细胞毒性中所起的具体作用及其与细胞膜的相互作用尚未明确。为阐明毒素-膜和毒素-受体相互作用在细胞毒性中的作用，我们建立了一个基于细胞的系统，该系统利用稳定表达Cry1Ab毒素的钙黏蛋白受体BT-R1的High Five昆虫细胞。Cry1Ab毒素以寡聚体和单体形式整合到细胞膜中。单体毒素特异性结合BT-R1，而寡聚毒素的整合是非特异性的且依赖于脂质。细胞膜中的毒素寡聚体不会产生裂解孔，也不会杀死昆虫细胞。相反，细胞死亡与Cry1Ab毒素单体与BT-R1的结合相关，这显然激活了一条Mg2+依赖的细胞信号通路。
