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Characterizing the mechanosensitive response of Paraburkholderia graminis membranes.
Biochimica et Biophysica Acta (BBA) - Biomembranes ( IF 2.8 ) Pub Date : 2020-01-07 , DOI: 10.1016/j.bbamem.2020.183176
Brittni L Miller 1 , Hannah M Dickinson 1 , Brian Wingender 2 , Albina Mikhaylova 2 , Hannah R Malcolm 1
Affiliation  

Bacterial mechanosensitive channels gate in response to membrane tension, driven by shifts in environmental osmolarity. The mechanosensitive channels of small conductance (MscS) and large conductance (MscL) from Escherichia coli (Ec) gate in response to mechanical force applied to the membrane. Ec-MscS is the foundational member of the MscS superfamily of ion channels, a diverse family with at least fifteen subfamilies identified by homology to the pore lining helix of Ec-MscS, as well as significant diversity on the N- and C-termini. The MscL family of channels are homologous to Ec-MscL. In a rhizosphere associated bacterium, Paraburkholderia graminis C4D1M, mechanosensitive channels are essential for cell survival during changing osmotic environments such as a rainstorm. Utilizing bioinformatics, we predicted six MscS superfamily members and a single MscL homologue. The MscS superfamily members fall into at least three subfamilies: bacterial cyclic nucleotide gated, multi-TM, and extended N-terminus. Osmotic downshock experiments show that wildtype P. graminis cells contain a survival mechanism that prevents cell lysis in response to hypoosmotic shock. To determine if this rescue is due to mechanosensitive channels, we developed a method to create giant spheroplasts of P. graminis to explore the single channel response to applied mechanical tension. Patch clamp electrophysiology on these spheroplasts shows two unique conductances: MscL-like and MscS-like. These conductances are due to likely three unique proteins. This indicates that channels that gate in response to mechanical tension are present in the membrane. Here, we report the first single channel evidence of mechanosensitive ion channels from P. graminis membranes.

中文翻译:

表征重症侧柏膜的机械敏感反应。

细菌机械敏感通道在环境渗透压变化的驱动下响应膜张力而门控。响应于施加到膜的机械力,来自大肠杆菌(Ec)门的小电导(MscS)和大电导(MscL)的机械敏感通道。Ec-MscS是离子通道MscS超家族的基础成员,该家族是一个离子家族,具有至少15个亚家族,这些家族通过与Ec-MscS的孔衬螺旋的同源性鉴定,并且在N-和C-末端具有显着的多样性。MscL通道家族与Ec-MscL同源。在根际相关细菌Paraparakholderia graminis C4D1M中,机械敏感通道对于在变化的渗透环境(例如暴雨)中的细胞存活至关重要。利用生物信息学,我们预测了六个MscS超家族成员和一个MscL同源物。MscS超家族成员至少分为三个亚家族:细菌环核苷酸门控的,multi-TM和扩展的N端。渗透性休克实验表明,野生型粉状疟原虫细胞包含一种存活机制,该机制可防止细胞因低渗性休克而裂解。为了确定这种抢救是否是由于机械敏感通道引起的,我们开发了一种方法来创建巨大的假单胞菌原生质球,以探索对施加机械张力的单通道反应。这些原生质球上的膜片钳电生理学显示了两种独特的电导:MscL样和MscS样。这些电导归因于可能的三种独特蛋白质。这表明响应于机械张力而选通的通道存在于膜中。这里,
更新日期:2020-01-07
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