Department of Cell Biology, University of Massachusetts Medical School, Worcester, 01655, USA.
J Cell Biol. 2009 Dec 28;187(7):1117-32. doi: 10.1083/jcb.200909183.
In humans, seven evolutionarily conserved genes that cause the cilia-related disorder Bardet-Biedl syndrome (BBS) encode proteins that form a complex termed the BBSome. The function of the BBSome in the cilium is not well understood. We purified a BBSome-like complex from Chlamydomonas reinhardtii flagella and found that it contains at least BBS1, -4, -5, -7, and -8 and undergoes intraflagellar transport (IFT) in association with a subset of IFT particles. C. reinhardtii insertional mutants defective in BBS1, -4, and -7 assemble motile, full-length flagella but lack the ability to phototax. In the bbs4 mutant, the assembly and transport of IFT particles are unaffected, but the flagella abnormally accumulate several signaling proteins that may disrupt phototaxis. We conclude that the BBSome is carried by IFT but is an adapter rather than an integral component of the IFT machinery. C. reinhardtii BBS4 may be required for the export of signaling proteins from the flagellum via IFT.
在人类中，七个导致纤毛相关疾病 Bardet-Biedl 综合征（BBS）的进化保守基因编码形成一个称为 BBSome 的复合物的蛋白质。BBSome 在纤毛中的功能尚未完全理解。我们从衣藻鞭毛中纯化了一个类似 BBSome 的复合物，发现它至少包含 BBS1、-4、-5、-7 和 -8，并与一部分 IFT 颗粒一起进行内鞭毛运输（IFT）。衣藻插入突变体在 BBS1、-4 和 -7 中缺陷，组装出能动的、全长的鞭毛，但缺乏光趋性的能力。在 bbs4 突变体中，IFT 颗粒的组装和运输不受影响，但鞭毛异常积累了几种可能破坏光趋性的信号蛋白。我们得出结论，BBSome 由 IFT 携带，但它是 IFT 机械的适配器而不是组成部分。衣藻 BBS4 可能需要通过 IFT 将信号蛋白从鞭毛中输出。
