A novel dynein light intermediate chain colocalizes with the retrograde motor for intraflagellar transport at sites of axoneme assembly in Chlamydomonas and mammalian cells
A novel dynein light intermediate chain colocalizes with the retrograde motor for intraflagellar transport at sites of axoneme assembly in Chlamydomonas and mammalian cells
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DOI：
10.1091/mbc.e02-10-0682
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发表时间：
2003-05-01
影响因子：
3.3
通讯作者：
Porter, ME
中科院分区：
文献类型：
--
作者：
Perrone, CA;Tritschler, D;Porter, ME
纤毛和鞭毛的组装依赖于鞭毛内双向运输(IFT)。顺行性IFT是由激动素H驱动的，而逆行性IFT则需要细胞质dynein 1b(CDHC1b)。人们对cDHC1b如何与其货物相互作用或如何监管知之甚少。最近的工作发现了一个新的动力蛋白轻中间链(D2LIC)，它与哺乳动物的cDHC1b同系物DHC2共定位于培养细胞的中心体区域。为了了解LIC是否可能在IFT中发挥作用，我们对编码D2LIC衣原体同源物的基因进行了鉴定，发现其表达在晕厥反应中上调。我们发现，在鞭毛分离、动力蛋白提取、蔗糖密度离心和免疫沉淀过程中，LIC亚单位与cDHC1b发生相互作用。免疫细胞化学显示，在野生型细胞中，LIC与cDHC1b共定位于基底体区域和鞭毛长度。在一组逆行IFT和长度控制突变体中，该复合体的定位发生了改变，这表明受影响的基因产物直接或间接调节cDHC1b的活性。哺乳动物的D2LIC和D2LIC在肺、脑和传出管的纤毛上皮的顶端细胞质和轴突中也有共存。这些研究，以及对破坏秀丽线虫逆行IFT的LIC突变XBX-1(Ok279)的鉴定表明，新的LIC是多种生物体中cDHC1b/DHC2逆行IFT马达的一个组成部分。
The assembly of cilia and flagella depends on bidirectional intraflagellar transport (IFT). Anterograde IFT is driven by kinesin H, whereas retrograde IFT requires cytoplasmic dynein 1b (cDHC1b). Little is known about how cDHC1b interacts with its cargoes or how it is regulated. Recent work identified a novel dynein light intermediate chain (D2LIC) that colocalized with the mammalian cDHC1b homolog DHC2 in the centrosomal region of cultured cells. To see whether the LIC might play a role in IFT, we characterized the gene encoding the Chlamydomonas homolog of D2LIC and found its expression is up-regulated in response to deflagellation. We show that the LIC subunit copurifies with cDHC1b during flagellar isolation, dynein extraction, sucrose density centrifugation, and immunoprecipitation. Immunocytochemistry reveals that the LIC colocalizes with cDHC1b in the basal body region and along the length of flagella in wild-type cells. Localization of the complex is altered in a collection of retrograde IFT and length control mutants, which suggests that the affected gene products directly or indirectly regulate cDHC1b activity. The mammalian DHC2 and D2LIC also colocalize in the apical cytoplasm and axonemes of ciliated epithelia in the lung, brain, and efferent duct. These studies, together with the identification of an LIC mutation, xbx-1(ok279), which disrupts retrograde IFT in Caenorhabditis elegans, indicate that the novel LIC is a component of the cDHC1b/DHC2 retrograde IFT motor in a variety of organisms.