Shape bistability of a membrane neck: A toggle switch to control vesicle content release
Shape bistability of a membrane neck: A toggle switch to control vesicle content release
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DOI：
10.1073/pnas.1432962100
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发表时间：
2003-07-22
影响因子：
11.1
通讯作者：
Zimmerberg, J
中科院分区：
文献类型：
--
作者：
Frolov, VA;Lizunov, VA;Zimmerberg, J
被认为是形状动力学和渗透性的膜颈连接囊泡和质膜。颈部由两个平行轴对称环之间延伸的脂膜小管模拟。在由膜的系统几何形状和机械性能定义的长度范围内，小管具有两种稳定的形状：悬链形微管和圆柱形纳米管。这两种形状的渗透性，测量为小管内部的离子电导率，相差高达四个数量级。在临界长度附近，形状之间的过渡发生在不到一毫秒的时间内。理论估计表明，形状转换是由一个单一的参数，小管长度控制。因此，小管连接可以作为一个导电性微动开关，在细胞过程中，如“吻和运行”胞吐作用，切换囊泡内容物的释放。为了支持这一观点，证明了巨噬细胞中囊泡和细胞质膜之间的膜连接的粘附行为。
Shape dynamics and permeability of a membrane neck connecting a vesicle and plasma membrane are considered. The neck is modeled by a lipid membrane tubule extended between two parallel axisymmetric rings. Within a range of lengths, defined by system geometry and mechanical properties of the membrane, the tubule has two stable shapes: catenoidal microtubule and cylindrical nanotubule. The permeabilities of these two shapes, measured as ionic conductivity of the tubule interior, differ by up to four orders of magnitude. Near the critical length the transitions between the shapes occur within less than a millisecond. Theoretical estimates show that the shape switching is controlled by a single parameter, the tubule length. Thus the tubule connection can operate as a conductivity microswitch, toggling the release of vesicle content in such cellular processes as "kiss-and-run" exocytosis. In support of this notion, bistable behavior of membrane connections between vesicles and the cell plasma membrane in macrophages is demonstrated.