SQL-1, homologue of the Golgi protein GMAP210, modulates intraflagellar transport in C. elegans
SQL-1, homologue of the Golgi protein GMAP210, modulates intraflagellar transport in C. elegans
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DOI：
10.1242/jcs.116640
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发表时间：
2013-04-15
影响因子：
4
通讯作者：
Jansen, Gert
中科院分区：
文献类型：
--
作者：
Broekhuis, Joost R.;Rademakers, Suzanne;Jansen, Gert
初级纤毛是基于微管的细胞器，具有重要的感觉功能。对于它们的功能，纤毛依赖于通过细胞内运输和鞭毛内运输（IFT）递送特定蛋白质。在秀丽隐杆线虫的纤毛中，顺行IFT由驱动蛋白-II和OSM-3介导。以前，我们已经表明，在两栖动物通道神经元中的显性活性G蛋白a亚基（GPA-3QL）的表达影响驱动蛋白II和OSM-3的协调，也影响纤毛长度，这表明环境信号可以调节这些过程。在这里，我们表明，失去功能的sql-1（抑制gpa-3QL 1），它编码的同源哺乳动物高尔基体蛋白GMAP 210，抑制gpa-3QL纤毛长度表型。SQL-1定位于高尔基体，在那里它有助于维持高尔基体的组织。sql-1的缺失本身并不影响纤毛的长度，而sql-1的过表达会导致纤毛变长。使用荧光标记的IFT蛋白质的实时成像，我们发现，在sql-1突变体OSM-3移动速度更快，驱动蛋白-II移动速度较慢，一些复杂的A和B蛋白质以中等速度移动，而其他人则以相同的速度移动OSM-3。这表明sql-1的突变使IFT复合物不稳定。最后，我们发现，同时失活的sql-1和激活的gpa-3QL影响的OSM-3的速度。总之，我们表明，在C。在线虫中，Golgin蛋白SQL-1在维持IFT复合物的稳定性中起重要作用。
Primary cilia are microtubule-based organelles that have important sensory functions. For their function, cilia rely on the delivery of specific proteins, both by intracellular trafficking and intraflagellar transport (IFT). In the cilia of Caenorhabditis elegans, anterograde IFT is mediated by kinesin-II and OSM-3. Previously, we have shown that expression of a dominant active G protein a subunit (GPA-3QL) in amphid channel neurons affects the coordination of kinesin-II and OSM-3 and also affects cilia length, suggesting that environmental signals can modulate these processes. Here, we show that loss-of-function of sql-1 (suppressor of gpa-3QL 1), which encodes the homologue of the mammalian Golgi protein GMAP210, suppresses the gpa-3QL cilia length phenotype. SQL-1 localizes to the Golgi apparatus, where it contributes to maintaining Golgi organization. Loss of sql-1 by itself does not affect cilia length, whereas overexpression of sql-1 results in longer cilia. Using live imaging of fluorescently tagged IFT proteins, we show that in sql-1 mutants OSM-3 moves faster, kinesin-II moves slower and that some complex A and B proteins move at an intermediate velocity, while others move at the same velocity as OSM-3. This indicates that mutation of sql-1 destabilizes the IFT complex. Finally, we show that simultaneous inactivation of sql-1 and activation of gpa-3QL affects the velocity of OSM-3. In summary, we show that in C. elegans the Golgin protein SQL-1 plays an important role in maintaining the stability of the IFT complex.