Cluap1/IFT38 is a ciliary protein that belongs to the IFT-B complex and is required for ciliogenesis. In this study, we have examined the behaviors of Cluap1 protein in nonciliated and ciliated cells. In proliferating cells, Cluap1 is located at the distal appendage of the mother centriole. When cells are induced to form cilia, Cluap1 is found in a novel noncentriolar compartment, the cytoplasmic IFT spot, which mainly exists once in a cell. Other IFT-B proteins such as IFT46 and IFT88 are colocalized in this spot. The cytoplasmic IFT spot is present in mouse embryonic fibroblasts (MEFs) but is absent in ciliogenesis-defective MEFs lacking Cluap1, Kif3a or Odf2. The cytoplasmic IFT spot is also found in mouse embryos but is absent in the Cluap1 mutant embryo. When MEFs are induced to form cilia, the cytoplasmic IFT spot appears at an early step of ciliogenesis but starts to disappear when ciliogenesis is mostly completed. These results suggest that IFT-B proteins such as Cluap1 accumulate in a previously undescribed cytoplasmic compartment during ciliogenesis.

中文翻译：

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纤毛虫结合的IFT-B蛋白在新型细胞质区室中的积累。

Cluap1 / IFT38是一种纤毛蛋白，属于IFT-B复合物，是纤毛发生所必需的。在这项研究中，我们已经检查了非纤毛和纤毛细胞中Cluap1蛋白的行为。在增殖细胞中，Cluap1位于母体的远端附肢。当诱导细胞形成纤毛时，在新型非中心体隔室中发现了Cluap1，该细胞质IFT点主要在细胞中存在一次。其他IFT-B蛋白（例如IFT46和IFT88）在此位置共定位。胞质IFT点存在于小鼠胚胎成纤维细胞（MEF）中，但在缺乏Cluap1，Kif3a或Odf2的纤毛发生缺陷型MEF中不存在。在小鼠胚胎中也发现了细胞质IFT点，但在Cluap1突变体胚胎中却不存在。当MEF被诱导形成纤毛时，胞质IFT点出现在纤毛形成的早期，但是当纤毛形成完成时开始消失。这些结果表明，在纤毛发生过程中，IFT-B蛋白（例如Cluap1）积累在以前未描述的胞质区室中。