Arrangement of tubulin subunits and microtubule-associated proteins in the central-pair microtubule apparatus of squid (Loligo pealei) sperm flagella.
Arrangement of tubulin subunits and microtubule-associated proteins in the central-pair microtubule apparatus of squid (Loligo pealei) sperm flagella.
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DOI：
10.1083/jcb.89.2.309
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发表时间：
1981-05
期刊：
影响因子：
--
通讯作者：
Langevin GL
中科院分区：
文献类型：
--
作者：
Linck RW;Olson GE;Langevin GL
这项研究对精子鞭毛的中央对微管装置进行了全面、高分辨率的结构分析。它描述了几种与微管相关的“鞘”成分的排列，并表明与之前的想法相反，微管在结构上是不对称的。中心对的两个微管在几个方面有所不同：C2 小管具有单排 18 nm 长的鞘突出，轴向周期为 16 nm，而 C1 小管具有多排 9 nm 的球状鞘组件，轴向重复为 32 nm。 C2 小管的管腔总是完全充满电子致密材料； C1 肾小管的肾小管通常是空心的。 C2 小管还具有一系列围绕微管排列的珠状链；珠状链由直径 7.5-10 nm 的球状亚基组成，似乎在 C1 和 C2 小管的配对中发挥作用。这些发现表明：珠链不是螺旋形的，而是以锁紧垫圈的形式排列在微管上，轴向周期为 16 nm； C2 小管中微管蛋白二聚体的晶格不是螺旋对称的，而是在某些原丝对之间存在接缝。所提出的晶格模型预测，由于这些接缝，中心对以及可能所有单线态微管可能包含一条由 2-5 条原丝组成的带，这些原丝具有抗溶解性；这些模型得到了随附论文结果的支持（R. W. Linck 和 G. L. Langevin. 1981. J. Cell Biol. 89: 323-337）。
This study provides a comprehensive, high-resolution structural analysis of the central-pair microtubule apparatus of sperm flagella. It describes the arrangement of several microtubule-associated "sheath" components and suggests, contrary to previous thinking, that microtubules are structurally asymmetric. The two microtubules of the central pair are different in several respects: the C2 tubule bears a single row of 18-nm-long sheath projections with an axial periodicity of 16 nm, whereas the C1 tubule possesses rows of 9-nm globular sheath components with an axial repeat of 32 nm. The lumen of the C2 tubule always appears completely filled with electron-dense material; that of the C1 tubule is frequently hollow. The C2 tubule also possesses a series of beaded chains arranged around the microtubule; the beaded chains are composed of globular subunits 7.5-10 nm in diameter and appear to function in the pairing of the C1 and C2 tubules. These findings indicate: that the beaded chains are not helical, but assume the form of lock washers arranged with a 16-nm axial periodicity on the microtubule; and that the lattice of tubulin dimers in the C2 tubule is not helically symmetric, but that there are seams between certain pairs of protofilaments. Proposed lattice models predict that, because of these seams, central pair and perhaps all singlet microtubules may contain a ribbon of 2-5 protofilaments that are resistant to solubilization; these models are supported by the results of the accompanying paper (R. W. Linck, and G. L. Langevin. 1981. J. Cell Biol. 89: 323-337.