Regulation of endocytosis, exocytosis, and shape by membrane tension
Regulation of endocytosis, exocytosis, and shape by membrane tension
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DOI：
10.1101/sqb.1995.060.01.060
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发表时间：
1995-01-01
期刊：
影响因子：
--
通讯作者：
Sheetz, MP
中科院分区：
文献类型：
--
作者：
Dai, J;Sheetz, MP
一般来说，膜的物理性质通常被认为是调节生物功能的重要因素。膜受体通常集中在域中，并且它们的横向聚集与功能激活有关。牵张激活通道和突触调节反应都有明确的机械成分。此外，膜可以通过线状系链施加非常显著的力，如迁移细胞或滚动淋巴细胞产生的收缩纤维所证明的。我们最近的特点是，细胞施加在膜栓作为细胞状态的函数的力量（戴和Sheetz 1995）。这些力明显大于单个马达分子所能产生的力。例如，在神经元生长锥中，一个与丝状伪足大小相似的系链膜在用于形成它的珠子上产生7 pN的力。单个肌球蛋白分子产生约3 pN的峰值力，在等长条件下甚至可能更小（Finer et al. 1994）。因此，如果肌球蛋白或某种类似的马达负责延伸丝状伪足，那么膜张力可能会阻止延伸，直到几个肌球蛋白分子被招募来为延伸提供动力。这表明，膜张力可以发挥重要作用，在调节机械酶参与膜运输和细胞形态的变化。
In general, the physical properties of membranes have often been suggested as significant factors in regulating biological functions. Membrane receptors are often concentrated in domains, and their lateral aggregation has been linked to functional activation. Stretch-activated channels and osmoregulatory responses all have a clear mechanical component. Furthermore, membranes can exert very significant forces through thread-like tethers, as evidenced by the retraction fibers that migrating cells or rolling lymphocytes generate. We have recently characterized the forces that cells exert on membrane tethers as a function of the cell state (Dai and Sheetz 1995). Those forces are significantly greater than the forces that single motor molecules can generate. For example, in the neuronal growth cone, a tether membrane similar in size to a filopodium creates a 7 pN force on the bead used to form it. Single myosin molecules generate a peak force of approximately 3 pN and possibly even less under isometric conditions (Finer et al. 1994). Thus, if myosin or some similar motor was responsible for extending a filopodium, the membrane tension could block extension until several myosin molecules were recruited to power extension. This suggests that membrane tension can play an important role in regulating mechanical enzymes involved in membrane trafficking and cell morphological changes.