论文标题
通过膜封闭结构中的孔通过孔扩散出口率
Diffusive Exit Rates Through Pores in Membrane-Enclosed Structures
论文作者
论文摘要
许多膜封闭的细胞内结构的功能依赖于通过膜中狭窄的孔或通道退出的扩散颗粒的释放。释放速率随孔径，密度和通道的长度而变化。我们提出了一个简单的近似模型，该模型用随机模拟验证，用于估算圆柱体的有效释放速率以及其他简单形状的域，这是通道参数的函数。结果表明，对于非常小的孔，散布在边界上的低密度通道足以实现颗粒释放的大量速率。此外，我们表明，增加被动通道的长度既可以降低释放速度，又导致对通道密度的陡峭依赖性较小。我们的结果与先前测量的局部钙释放速率进行了比较，从内质网的小管中进行了比较，从而估算了导致观察到的钙外排的相关通道密度。
The function of many membrane-enclosed intracellular structures relies on release of diffusing particles that exit through narrow pores or channels in the membrane. The rate of release varies with pore size, density, and length of the channel. We propose a simple approximate model, validated with stochastic simulations, for estimating the effective release rate from cylinders, and other simple-shaped domains, as a function of channel parameters. The results demonstrate that, for very small pores, a low density of channels scattered over the boundary is sufficient to achieve substantial rates of particle release. Furthermore, we show that increasing the length of passive channels will both reduce release rates and lead to a less steep dependence on channel density. Our results are compared to previously-measured local calcium release rates from tubules of the endoplasmic reticulum, providing an estimate of the relevant channel density responsible for the observed calcium efflux.
