Unidad de Biofísica, CSIC-UPV/EHU, Universidad del País Vasco, Barrio Sarriena s/n, Leioa, Spain.
Orig Life Evol Biosph. 2011 Jun;41(3):281-304. doi: 10.1007/s11084-010-9225-y. Epub 2010 Nov 17.
Mechanosensitive (MS) channels can prevent bacterial bursting during hypo-osmotic shocks by responding to increases in lateral tension at the membrane level through an integrated and coordinated opening mechanism. Mechanical regulation in protocells could have been one of the first mechanisms to evolve in order to preserve their integrity against changing environmental conditions. How has the rich functional diversity found in present cells been created throughout evolution, and what did the primordial MS channels look like? This review has been written with the aim of identifying which factors may have been important for the appearance of the first osmotic valve in a prebiotic context, and what this valve may have been like. It highlights the mechanical properties of lipid bilayers, the association of peptides as aggregates in membranes, and the conservation of sequence motifs as central aspects to understand the evolution of proteins that gate below the tension required for spontaneous pore formation and membrane rupture. The arguments developed here apply to both MscL and MscS homologs, but could be valid to mechano-susceptible proteins in general.
机械敏感性 (MS) 通道可以通过响应膜水平上的侧向张力增加来防止细菌在低渗冲击下爆裂，通过整合和协调的开放机制。原细胞中的机械调节可能是为了在不断变化的环境条件下保持其完整性而首先进化的机制之一。在进化过程中，如何创造出现在细胞中发现的丰富功能多样性，原始的 MS 通道是什么样子的？本综述的目的是确定在原核环境中出现第一个渗透阀的重要因素，以及这个阀可能是什么样子。它强调了脂质双层的机械特性、肽作为膜中聚集体的结合，以及序列基序的保守性，这些都是理解能够在自发孔形成和膜破裂所需的张力以下门控的蛋白质进化的核心方面。这里提出的论点既适用于 MscL 和 MscS 同源物，也可能适用于一般的机械敏感蛋白。
