Structure and Function of the Ciliary Pore Complex

 描述（由申请人提供）：纤毛是基于微管的细胞器，参与多种细胞过程，包括信号传导和运动。蛋白质进入纤毛是一个严格调控的过程，纤毛定位蛋白质的缺陷被认为是许多纤毛病的根本原因，这些纤毛病表现为囊性肾病、色素性视网膜炎和/或其他缺陷。进入纤毛的蛋白质似乎是控制在纤毛基地，纤毛孔假设存在。我们的研究小组提出睫状孔在分子组成和调节机制上与核孔高度相似。特别是，我们已经证明了已知参与核运输的蛋白质--小GTCRan Ran、其结合伙伴importins和核孔蛋白--存在于纤毛基部或纤毛内 并调节蛋白质进入睫状室。基于我们的初步数据，我们现在提出了一个模型，其中两个不同的机制调节进入睫状室：进入胞质蛋白质是由核孔蛋白的睫状孔复合体（CPC），并需要驱动蛋白马达和鞭毛内运输（IFT），而进入膜蛋白的过渡区（TZ）的分子调节，是IFT独立。我们将测试这个模型，结合活细胞，单分子和超分辨率显微镜技术，使用核孔蛋白和驱动蛋白运动功能的诱导抑制。这些研究将引导该领域的理解纤毛门控机制，并将在确定纤毛孔的性质及其与核孔的关系方面取得重要进展。

 DESCRIPTION (provided by applicant): Cilia are microtubule-based organelles that are involved in multiple cellular processes including signaling and motility. Protein entry into cilia s a tightly regulated process and defects in cilia-localized proteins are felt to be a root cause of many ciliopathies that manifest as cystic kidney disease, retinitis pigmentosa and/or other defects. The entry of proteins into cilia appears to be controlled at the cilia base where a ciliar pore is hypothesized to exist. Our group has proposed that the ciliary pore is highly analogous to the nuclear pore in its molecular composition and regulatory mechanism. In particular, we have demonstrated that proteins known to be involved in nuclear trafficking - the small GTPase Ran, its binding partners the importins, and nucleoporins - are present at the base or within cilia and regulate protein entry into the ciliary compartment. Based on our Preliminary Data, we now propose a model where two distinct mechanisms regulate entry into the ciliary compartment: entry of cytosolic proteins is regulated by nucleoporins of the ciliary pore complex (CPC) and requires kinesin motors and intraflagellar transport (IFT) whereas entry of membrane proteins is regulated by molecules of the transition zone (TZ) and is IFT-independent. We will test this model using inducible inhibition of nucleoporin and kinesin motor function combined with live-cell, single-molecule, and super-resolution microscopy techniques. These studies will lead the field forward in understanding ciliary gating mechanisms and will make important inroads in defining the nature of the cilia pore and its relation to the nuclear pore.