Intramanchette transport (IMT): Managing the making of the spermatid head, centrosome, and tail
Intramanchette transport (IMT): Managing the making of the spermatid head, centrosome, and tail
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DOI：
10.1002/mrd.10179
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发表时间：
2002-09-01
影响因子：
2.5
通讯作者：
Kierszenbaum, AL
中科院分区：
文献类型：
--
作者：
Kierszenbaum, AL
膜内转运(IMT)和鞭毛内转运(IFT)具有相似的分子组成：RAFT蛋白复合体运输由分子马达沿微管动员的货物蛋白。IFT最初是在衣藻的鞭毛中发现的，后来在线虫的纤毛和小鼠的纤毛和鞭毛细胞中也观察到了IFT。IFT被定义为一种蛋白质RAFT组分(也称为IFT颗粒)通过kinesin-II在鞭毛和质膜之间顺行移位，通过细胞质dynein 1b逆行移位的机制。编码RAFT蛋白复合体成分之一的Tg737基因突变，在小鼠中被命名为Polaris，在衣藻和小鼠中都被命名为IFT88，导致纤毛发生和鞭毛发育缺陷，以及左右轴确定的不对称。Polaris/IFT88在小鼠和大鼠精子细胞的套筒中检测到。IMT机制的迹象源于发现，一旦套筒拆解，与套筒相关的两种蛋白质(Sak57/K5和TBP-1，后者是26S蛋白酶体的组成部分)重新定位到中心体和精子尾部。IMT具有IFT机制的特征，但此外，它还促进精子发生过程中的核质交换活动。一个例子是RAN，它是一种小的GTP酶，存在于圆形精子细胞的细胞核和细胞质中，以及细长精子细胞的套架中。当套垫解体时，在细长精子细胞的中心体区域发现了RAN GTP酶。由于分子马达和RAFT蛋白的缺陷会导致视网膜中有缺陷的鞭毛、纤毛和含纤毛的光感受器细胞，IMT和IFT正在成为管理精子发育关键方面的重要机制。Ran GTP酶在核质转运中的具体作用及其从套筒到中心体再到精子尾部的定位还有待阐明。摩尔。是Reprod。戴夫。63：1-4,2002。(C)2002年Wiley-Liss，Inc.
Intramanchette transport (IMT) and intraflagellar transport (IFT) share similar molecular components: a raft protein complex transporting cargo proteins mobilized along microtubules by molecular motors. IFT, initially discovered in flagella of Chlamydomonas, has been also observed in cilia of the worm Caenorhabditis elegans and in mouse ciliated and flagellated cells. IFT has been defined as the mechanism by which protein raft components (also called IFT particles) are displaced between the flagellum and the plasma membrane in the anterograde direction by kinesin-II and in the retrograde direction by cytoplasmic dynein 1b. Mutation of the gene Tg737, encoding one of the components of the raft protein complex, designated Polaris in the mouse and IFT88 in both Chlamydomonas and mouse, results in defective ciliogenesis and flagellar development as well as asymmetry in left-right axis determination. Polaris/IFT88 is detected in the manchette of mouse and rat spermatids. Indications of an IMT mechanism originated from the finding that two proteins associated with the manchette (Sak57/K5 and TBP-1, the latter a component of the 26S proteasome) repositioned to the centrosome and sperm tail once the manchette disassembled. IMT has the features of the IFT machinery but, in addition, facilitates nucleocytoplasmic exchange activities during spermiogenesis. An example is Ran, a small GTPase present in the nucleus and cytoplasm of round spermatids and in the manchette of elongating spermatids. Upon disassembly of the manchette, Ran GTPase is found in the centrosome region of elongating spermatids. Because defective molecular motors and raft proteins result in defective flagella, cilia, and cilia-containing photoreceptor cells in the retina, IMT and IFT are emerging as essential mechanisms for managing critical aspects of sperm development. Details of specific role of Ran GTPase in nucleocytoplasmic transport and its relocation from the manchette to the centrosome to the sperm tail await elucidation. Mol. Reprod. Dev. 63: 1-4, 2002. (C) 2002 Wiley-Liss, Inc.