Mechanosensitive channel MscS is critical for termination of the bacterial hypoosmotic permeability response.
Mechanosensitive channel MscS is critical for termination of the bacterial hypoosmotic permeability response.
复制标题
DOI：
10.1085/jgp.202213168
复制
发表时间：
2023-05-01
期刊：
影响因子：
--
通讯作者：
中科院分区：
文献类型：
--
作者：
研究了E.结合细菌存活率分析大肠杆菌。结果表明，MscL，高阈值的“紧急释放阀”，拯救细菌从向下冲击只有在MscS，MscK，或其他低阈值通道的存在下，这是必要的安抚MscL在释放阶段结束。自由生活的微生物在渗透压方面会发生剧烈变化。为了避免在突然的渗透压下降冲击下的裂解，细菌通过张力激活通道MscL、MscS和MscK快速排出小的代谢物。我们研究了五个染色体敲除菌株，p53 mscL，p53 mscS，双敲除p53 mscS p53 mscK，和三敲除p53 mscL p53 mscS p53 mscK，与野生型亲本菌株相比。停流实验证实，MscS和MscL介导快速渗透压释放和抑制细胞肿胀，但渗透活力测定表明，它们是不等价的。单独的MscS能够拯救细胞群，但在一些菌株中，MscL不能拯救，并且在不存在MscS和MscK的情况下另外变得有毒。此外，MscS上调的mscL菌株，这表明两个基因/蛋白质之间的串扰或mscS表达的细胞力学的影响。数据表明，对于适当终止的渗透率响应，高阈值（MscL）和低阈值（MscS/MscK）通道必须依次行动。在没有低阈值通道的情况下，在释放阶段结束时，MscL应将膜张力稳定在约10 mN/m。膜片钳协议模拟释放阶段的张力变化表明，非失活MscL，驻留在自己的张力阈值，闪烁，并产生持久的泄漏。当存在时，MscS/MscK群体在此阶段保持开放以将张力降低到MscL阈值以下并使大通道沉默。当MscS达到其自身的阈值时，其失活，从而确保适当终止低渗渗透性反应。表达非失活MscS突变体的细菌的受损渗透存活进一步支持高阈值通道和低阈值通道之间的这种功能性相互作用。
The kinetics of hypotonic osmolyte release from E. coli is analyzed in conjunction with bacterial survival. It is shown that MscL, the high-threshold “emergency release valve,” rescues bacteria from down-shocks only in the presence of MscS, MscK, or other low-threshold channels that are necessary to pacify MscL at the end of the release phase. Free-living microorganisms are subjected to drastic changes in osmolarity. To avoid lysis under sudden osmotic down-shock, bacteria quickly expel small metabolites through the tension-activated channels MscL, MscS, and MscK. We examined five chromosomal knockout strains, ∆mscL, ∆mscS, a double knockout ∆mscS ∆mscK, and a triple knockout ∆mscL ∆mscS ∆mscK, in comparison to the wild-type parental strain. Stopped-flow experiments confirmed that both MscS and MscL mediate fast osmolyte release and curb cell swelling, but osmotic viability assays indicated that they are not equivalent. MscS alone was capable of rescuing the cell population, but in some strains, MscL did not rescue and additionally became toxic in the absence of both MscS and MscK. Furthermore, MscS was upregulated in the ∆mscL strain, suggesting either a crosstalk between the two genes/proteins or the influence of cell mechanics on mscS expression. The data shows that for the proper termination of the permeability response, the high-threshold (MscL) and the low-threshold (MscS/MscK) channels must act sequentially. In the absence of low-threshold channels, at the end of the release phase, MscL should stabilize membrane tension at around 10 mN/m. Patch-clamp protocols emulating the tension changes during the release phase indicated that the non-inactivating MscL, residing at its own tension threshold, flickers and produces a protracted leakage. The MscS/MscK population, when present, stays open at this stage to reduce tension below the MscL threshold and silence the large channel. When MscS reaches its own threshold, it inactivates and thus ensures proper termination of the hypoosmotic permeability response. This functional interplay between the high- and low-threshold channels is further supported by the compromised osmotic survival of bacteria expressing non-inactivating MscS mutants.
登录
查看更多内容
DOI：
10.4161/chan.20998
发表时间：
2012-07
期刊：
Channels (Austin, Tex.)
影响因子：
--
作者：
Edwards MD;Black S;Rasmussen T;Rasmussen A;Stokes NR;Stephen TL;Miller S;Booth IR
通讯作者：
Booth IR
影响因子：
11.4
作者：
Li, YZ;Moe, PC;Blount, P
通讯作者：
Blount, P
影响因子：
3.4
作者：
Chiang, CS;Anishkin, A;Sukharev, S
通讯作者：
Sukharev, S
DOI：
10.1085/jgp.200910371
发表时间：
2010-06
期刊：
The Journal of general physiology
影响因子：
--
作者：
Belyy V;Kamaraju K;Akitake B;Anishkin A;Sukharev S
通讯作者：
Sukharev S
DOI：
10.1085/jgp.200409198
发表时间：
2005-02
期刊：
The Journal of general physiology
影响因子：
--
作者：
Akitake B;Anishkin A;Sukharev S
通讯作者：
Sukharev S