Regulation of Flagellar Assembly in Chlamydomonas

描述(申请人提供)：这项研究的长期目标是了解真核细胞用来调节纤毛和鞭毛组装的机制。衣藻的鞭毛保持恒定的长度，但LF1、LF2、LF3和LF4四个不同基因的突变会导致细胞失去组装控制，鞭毛生长到正常长度的三倍。这些基因中的两个编码了研究得很好的基因家族的成员：一个是MAP激酶，另一个是CDK家族的一个激酶。对四个LF基因的分析得出结论：LF4是一种新的MAP激酶，它通过缩短鞭毛来加强鞭毛长度的控制。LF1、LF2和LF3似乎共同调节长度，可能是通过调节逆行鞭毛内转运(IFT)。在接下来的项目期间，这个项目的具体目标将解决以下问题：L)什么蛋白质调节由LF4基因编码的MAP激酶酶，LF4p磷酸化什么蛋白质？2)假定的LF1/LF2/LF3细胞质复合体中的蛋白质如何相互作用，这个复合体如何调节LF2蛋白激酶？3)LF2蛋白激酶的蛋白质底物是什么，这些靶标的磷酸化如何调节鞭毛长度？4)长鞭毛突变体在鞭毛内运输(IFT)中显示变化吗？纤毛和鞭毛长期以来一直被认为在涉及液体在表面上移动或细胞在液体中移动的过程中发挥关键作用。最近，纤毛和鞭毛在发育早期具有关键功能已变得很清楚。纤毛和鞭毛的组装缺陷与多囊肾病、视网膜变性、倒位等哺乳动物发育过程中的问题有关。了解衣藻鞭毛组装的调节为理解哺乳动物系统中的这种组装提供了一个强大的模型。

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.