Regulation of Flagellar Assembly in Chlamydomonas

描述（由申请人提供）：本研究的长期目标是了解真核细胞用于调节纤毛和鞭毛组装的机制。衣原体的鞭毛保持恒定的长度，但四种不同基因的突变：LF1，LF2，LF3和LF4，导致细胞失去对组装的控制，鞭毛长到正常长度的三倍。这些基因中的两个编码被充分研究的基因家族的成员：MAP激酶和CDK家族的激酶。四个LF基因的分析得出的结论是，LF4，一种新的MAP激酶，通过缩短鞭毛来执行鞭毛长度控制。LF1，LF2和LF3似乎共同作用，以调节长度，可能通过调节逆行鞭毛内运输（IFT）。在下一个项目期间，该项目的具体目标将解决以下问题：l）哪些蛋白质调节LF4基因编码的MAP激酶，LF4p磷酸化哪些蛋白质？2)推定的LF1/LF2/LF3胞质复合物中的蛋白质如何相互作用，以及该复合物如何调节LF2蛋白激酶？3)LF2蛋白激酶的蛋白质底物是什么？这些靶点的磷酸化如何调节鞭毛长度？4)长鞭毛突变体是否显示鞭毛内转运（IFT）的改变？纤毛和鞭毛长期以来一直被认为在涉及液体在表面上的运动或细胞在液体中的运动的过程中发挥关键作用。最近已经清楚纤毛和鞭毛在发育早期具有关键功能。纤毛和鞭毛装配的缺陷与多囊肾病、视网膜变性、反位和哺乳动物发育中的其他问题有关。了解鞭毛组装在衣原体的调节提供了一个强大的模型，了解这种组装在哺乳动物系统。

DESCRIPTION (provided by applicant): The long-term goal of this research is to understand the mechanisms eukaryotic cells use to regulate the assembly of cilia and flagella. The flagella of Chlamydomonas are maintained at a constant length, but mutations in four different genes: LF1, LF2, LF3 and LF4, cause the cells to lose control of assembly and grow flagella up to three times normal length. Two of these genes encode members of well-studied gene families: a MAP kinase and a kinase of the CDK family. Analysis of the four LF genes leads to the conclusion that LF4, a novel MAP kinase, acts to enforce flagellar length control by shortening the flagella. LF1, LF2 and LF3 appear to act together to regulate length, perhaps by regulating retrograde intraflagellar transport (IFT). During the next project period the specific aims of this project will address the following questions:l) What proteins regulate the MAP kinase enzyme encoded by the LF4 gene, and what proteins does LF4p phosphorylate? 2) How do the proteins in the putative LF1/LF2/LF3 cytoplasmic complex interact, and how does this complex regulate the LF2 protein kinase? 3) What are the protein substrates of the LF2 protein kinase and how does phosphorylation of these targets regulate flagellar length? 4) Do the long-flagella mutants show alterations in intraflagellar transport (IFT)? Cilia and flagella have long been known to play key roles in processes that involve the movement of fluids over surfaces or the movement of cells through fluids. More recently it has become clear that cilia and flagella have critical functions early in development. Defects in the assembly of cilia and flagella have been connected to polycystic kidney disease retinal degeneration, situs inversus, and other problems in mammalian development. Understanding the regulation of flagellar assembly in Chlamydomonas provides a powerful model for understanding this assembly in mammalian systems.