Fluctuations of the red blood cell membrane: Relation to mechanical properties and lack of ATP dependence
Fluctuations of the red blood cell membrane: Relation to mechanical properties and lack of ATP dependence
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DOI：
10.1529/biophysj.107.117952
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发表时间：
2008-05-15
影响因子：
3.4
通讯作者：
Sleep, John
中科院分区：
文献类型：
--
作者：
Evans, James;Gratzer, Walter;Sleep, John
我们分析了红细胞膜在时间(欧米伽(S-1))和空间(Q(m(-1)频域的波动。细胞在渗透压范围内被检测，导致细胞体积是等渗态细胞体积的50%到170%。等渗细胞的波动表现出类似于Q(-3)的依赖关系，表明运动以弯曲为主，推测的弯曲模数类似于9×10(-19)J。当细胞被渗透膨胀到恰好低于裂解点(生理体积的166%)时，波动的Q(-1)依赖叠加，这意味着运动现在由膜张力主导；估计类似于1.3×10(-4)nm(-1)。另一方面，当细胞处于渗透脱水状态时，波动幅度逐渐减小。这是由内部粘度的上升引起的，对重新密封的含有降低的血红蛋白浓度的幽灵的测量表明，没有这种影响。此外，我们还检查了细胞在棘粒细胞增多症开始之前耗尽的三磷酸腺苷，并且没有观察到波动幅度的变化。我们得出的结论是，膜。红细胞的功能受弯曲模数、膜张力和胞浆粘度的控制，很少或根本不依赖于ATP的存在或不存在。
We have analyzed the fluctuations of the red blood cell membrane in both the temporal ((omega(S-1)) and spatial (q(m(-1))) frequency domains. The cells were examined over a range of osmolarities leading to cell volumes from 50% to 170% of that in the isotonic state. The fluctuations of the isotonic cell showed an similar to q(-3)-dependence, indicative of a motion dominated by bending, with an inferred bending modulus of similar to 9 x 10(-19) J. When the cells were osmotically swollen to just below the point of lysis (166% of physiological volume), a q(-1)-dependence of the fluctuations supervened, implying that the motion was now dominated by membrane tension; estimated as similar to 1.3 x 10(-4) nm(-1). When, on the other hand, the cells were osmotically dehydrated, the fluctuation amplitude progressively decreased. This was caused by a rise in internal viscosity, as shown by measurements on resealed ghosts containing a reduced hemoglobin concentration, which displayed no such effect. We examined, in addition, cells depleted of ATP, before the onset of echinocytosis, and could observe no change in fluctuation amplitude. We conclude that the membrane. uctuations of the red cell are governed by bending modulus, membrane tension, and cytosolic viscosity, with little or no dependence on the presence or absence of ATP.