Formation of very large conductance channels by Bacillus cereus Nhe in Vero and GH(4) cells identifies NheA + B as the inherent pore-forming structure.
Formation of very large conductance channels by Bacillus cereus Nhe in Vero and GH(4) cells identifies NheA + B as the inherent pore-forming structure.
复制标题
DOI：
10.1007/s00232-010-9298-6
复制
发表时间：
2010-09
影响因子：
2.4
通讯作者：
Hardy, Simon P.
中科院分区：
文献类型：
--
作者：
Haug, Trude M.;Sand, Sverre L.;Sand, Olav;Phung, Danh;Granum, Per E.;Hardy, Simon P.
关键词：
蜡样芽孢杆菌产生的非溶血性肠毒素（Nhe）是由NheA、-B和-C三种成分组成的致孔毒素。本研究通过测定Nhe对灵长类动物上皮细胞（Vero）和啮齿类动物垂体细胞（GH_4）乳酸脱氢酶（LDH）释放、K ~+外流和胞浆Ca ~（2+）浓度（[Ca ~（2+）]i）的影响，研究了Nhe对细胞内Ca ~（2+）浓度的影响。膜片钳记录监测质膜通道事件。使用B. cereus缺乏NheA或-C，我们研究了各种成分的功能作用。在两种细胞类型中，NheA + B + C诱导LDH和K+的释放以及Ca 2+内流。抗NheB单克隆抗体可阻断LDH释放和[Ca ~（2+）]i升高。NheA + B与NheA + B + C作用后，GH4细胞K+外流率和[Ca ~（2+）]i升高，而Vero细胞K+外流率降低50%，[Ca ~（2+）]i未受影响。NheB + C对两种细胞类型均无影响。暴露于NheA + B + C诱导两种细胞类型中的大电导步骤，并且在暴露于NheA + B的GH4细胞中观察到类似的通道插入。在Vero细胞中，NheA + B诱导的通道电导小得多。NheB + C未能插入膜通道。GH_4细胞大通道的电导约为10 nS。这是在准生理条件下在细胞膜中报道的最大通道电导。总之，NheA和NheB是必要的和足够的大电导通道的形成在GH4细胞，而在Vero细胞中，这样的大电导通道是另外依赖于NheC。
The nonhemolytic enterotoxin (Nhe) produced by Bacillus cereus is a pore-forming toxin consisting of three components, NheA, -B and -C. We have studied effects of Nhe on primate epithelial cells (Vero) and rodent pituitary cells (GH4) by measuring release of lactate dehydrogenase (LDH), K+ efflux and the cytosolic Ca2+ concentration ([Ca2+]i). Plasma membrane channel events were monitored by patch-clamp recordings. Using strains of B. cereus lacking either NheA or -C, we examined the functional role of the various components. In both cell types, NheA + B + C induced release of LDH and K+ as well as Ca2+ influx. A specific monoclonal antibody against NheB abolished LDH release and elevation of [Ca2+]i. Exposure to NheA + B caused a similar K+ efflux and elevation of [Ca2+]i as NheA + B + C in GH4 cells, whereas in Vero cells the rate of K+ efflux was reduced by 50% and [Ca2+]i was unaffected. NheB + C had no effect on either cell type. Exposure to NheA + B + C induced large-conductance steps in both cell types, and similar channel insertions were observed in GH4 cells exposed to NheA + B. In Vero cells, NheA + B induced channels of much smaller conductance. NheB + C failed to insert membrane channels. The conductance of the large channels in GH4 cells was about 10 nS. This is the largest channel conductance reported in cell membranes under quasi-physiological conditions. In conclusion, NheA and NheB are necessary and sufficient for formation of large-conductance channels in GH4 cells, whereas in Vero cells such large-conductance channels are in addition dependent on NheC.
登录
查看更多内容
影响因子：
3.1
作者：
Lindback, Toril;Hardy, Simon P.;Maertlbauer, Erwin
通讯作者：
Maertlbauer, Erwin
影响因子：
2.8
作者：
Fagerlund, Annette;Lindback, Toril;Hardy, Simon P.
通讯作者：
Hardy, Simon P.
影响因子：
2.8
作者：
Lindbäck, T;Fagerlund, A;Granum, PE
通讯作者：
Granum, PE
影响因子：
4.4
作者：
Dietrich, R;Moravek, M;Märtlbauer, E
通讯作者：
Märtlbauer, E
影响因子：
2.1
作者：
Lund, T;Granum, PE
通讯作者：
Granum, PE