Direct measurement of actin polymerization rate constants by electron microscopy of actin filaments nucleated by isolated microvillus cores.
Direct measurement of actin polymerization rate constants by electron microscopy of actin filaments nucleated by isolated microvillus cores.
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通过肌动蛋白丝的电子显微镜对肌动蛋白聚合速率常数直接测量，该肌动蛋白丝由分离的微绒毛核成核。
DOI：
10.1083/jcb.88.3.654
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发表时间：
1981-03
影响因子：
7.8
通讯作者：
Mooseker, M S
中科院分区：
文献类型：
--
作者：
Pollard, T D;Mooseker, M S
我们使用从肠道刷状缘微绒毛分离的肌动蛋白细丝束，将纯肌肉肌动蛋白单体聚合成细丝。电子显微镜通过测量细丝长度随时间的变化来确定生长速度。生长速度与肌动蛋白单体浓度的线性关系提供了生长纤维两端单体结合和解离的速率常数。快速生长(“带刺”)端的缔合和解离速率常数高于缓慢生长(“尖端”)端。这些速率常数在20 mM KCl中的值不同于75 mM KCl和5 mM MgSO4中的值。2微米细胞松弛素B明显通过将缔合速率常数和解离速率常数都降低到接近于零来完全阻止生长，但对尖端的生长只有很小程度的抑制。
We used actin filament bundles isolated from intestinal brush-border microvilli to nucleate the polymerization of pure muscle actin monomers into filaments. Growth rates were determined by electron microscopy by measuring the change in the length of the filaments as a function of time. The linear dependence of the growth rates on the actin monomer concentration provided the rate constants for monomer association and dissociation at the two ends of the growing filament. The rapidly growing ("barbed") end has higher association and dissociation rate constants than the slowly growing ("pointed") end. The values of these rate constants differ in 20 mM KCl compared with 75 mM KCl, 5 mM MgSO4. 2 microM cytochalasin B blocks growth entirely at the barbed end, apparently by reducing both association and dissociation rate constants to near zero, but inhibits growth at the pointed end to only a small extent.