Roles of TOG and jelly-role domains of centrosomal protein CEP104 in its functions in cilium elongation and Hedgehog signaling.
Roles of TOG and jelly-role domains of centrosomal protein CEP104 in its functions in cilium elongation and Hedgehog signaling.
复制标题
中心体蛋白 CEP104 的 TOG 和果冻作用域在纤毛伸长和 Hedgehog 信号传导中的作用。
DOI：
10.1074/jbc.ra120.013334
复制
发表时间：
2020
期刊：
影响因子：
--
通讯作者：
K.
中科院分区：
文献类型：
--
作者：
Yamazoe;T.;Nagai;T.;Umeda;S.;Sugaya;Y.;and Mizuno;K.
初级纤毛是通过微管为基础的轴丝的延伸产生的。中心体蛋白104（CEP 104）定位于延长轴丝的顶端，CEP 104突变与纤毛病Joubert综合征有关。因此，CEP 104与纤毛发生有关。然而，CEP 104调节纤毛发生的机制仍然难以捉摸。我们在这里报告，CEP 104是至关重要的纤毛伸长，但不是启动纤毛发生。我们还证明了CEP 104的肿瘤过表达基因（TOG）结构域具有微管聚合活性，并且这种活性对于CEP 104的纤毛延长活性是必不可少的。敲除/拯救实验表明，N-末端卷曲（JR）折叠部分有助于CEP 104的纤毛延长活性，但锌指区和SXIP基序都不是该活性所必需的。CEP 104通过锌指区与中心粒加帽蛋白CP 110结合，通过SXIP基序与微管加末端结合蛋白EB 1结合，表明CP 110和EB 1的结合与CEP 104的纤毛延长活性无关。此外，CEP 104耗尽并不影响CP 110从母中心粒的去除，这表明CEP 104在去除CP 110后起作用。最后，我们还表明，CEP 104是所需的纤毛进入Smoothened和出口的GPR 161后，刺猬信号激活和TOG结构域在这一活动中起着关键作用。我们的研究结果确定了CEP 104的各个结构域在纤毛伸长和Hedgehog信号传导中的作用，并应增强我们对CEP 104突变相关纤毛病机制的理解。
Primary cilia are generated through the extension of the microtubule-based axoneme. Centrosomal protein 104 (CEP104) localizes to the tip of the elongating axoneme, andCEP104mutations are linked to a ciliopathy, Joubert syndrome. Thus, CEP104 has been implicated in ciliogenesis. However, the mechanism by which CEP104 regulates ciliogenesis remains elusive. We report here that CEP104 is critical for cilium elongation but not for initiating ciliogenesis. We also demonstrated that the tumor-overexpressed gene (TOG) domain of CEP104 exhibits microtubule-polymerizing activity and that this activity is essential for the cilium-elongating activity of CEP104. Knockdown/rescue experiments showed that the N-terminal jelly-roll (JR) fold partially contributes to cilium-elongating activity of CEP104, but neither the zinc-finger region nor the SXIP motif is required for this activity. CEP104 binds to a centriole-capping protein, CP110, through the zinc-finger region and to a microtubule plus-end–binding protein, EB1, through the SXIP motif, indicating that the binding of CP110 and EB1 is dispensable for the cilium-elongating activity of CEP104. Moreover, CEP104 depletion does not affect CP110 removal from the mother centriole, which suggests that CEP104 functions after the removal of CP110. Last, we also showed that CEP104 is required for the ciliary entry of Smoothened and export of GPR161 upon Hedgehog signal activation and that the TOG domain plays a critical role in this activity. Our results define the roles of the individual domains of CEP104 in its functions in cilium elongation and Hedgehog signaling and should enhance our understanding of the mechanism underlyingCEP104mutation–associated ciliopathies.