Vesicular Transport Mechanisms in Centrosome Regulation and Ciliogenesis

中心体是直接影响间期的微管、成核和组织细胞器。 微管阵列、有丝分裂纺锤体和纤毛。尽管它们在发展和联系方面具有重要意义 癌症、纤毛疾病和出生缺陷等疾病，中心体功能的基本方面和 人们对复制仍然知之甚少。例如，细胞器中的一些蛋白质充当了它的屏障 复制，而另一些则抑制纤毛的组装，因此，必须在 细胞周期来实现这些事件的循序渐进。目前，人们认为扩散是 解释了大多数中心体蛋白质的交换。然而，中心体蛋白的运输 靠近或远离中心体是一种看似合理但相对未被探索的控制机制 中心体复制与纤毛发生。之前，我们展示了内吞调节蛋白， EHD1是一种纤毛发生的调节因子，它通过介导中心体上远端附件小泡的融合来调节纤毛的发生 形成睫状囊。我们的数据支持EHD1在控制中心体方面的额外作用 复制周期，通过促进Cep215、CP110和周中心素(PCNT)的重新分布 在有丝分裂过程中，中心体转移到纺锤体中体，有效地消除了这些蛋白质障碍 中心体复制。我们的发现还涉及到几个与EHD1互动的合作伙伴，包括 Retromer和Mical-L1。值得注意的是，我们现在发现Mical-L1锚定在中心体/中心粒上 通过与微管蛋白结合，突出了它可能作为EHD1到 中心体。这项申请的目的是确定囊泡运输是否是一种新的 中心体复制周期和纤毛形成的基本调节器。我们的中心假设是 EHD1/Mical-L1/Retmer循环复合体促进囊泡传输机制来剥离 来自中心体的特定调节蛋白，从而使中心体复制和 纤毛发生。我们的具体目标是：1.)阐明内吞囊泡排出的机制 中心体中的中心粒和PCM蛋白。我们假设EHD1(细胞质的存在 内吞泡面)与中心粒的远端附属物对接，可能通过Mical-L1， 与中心粒蛋白CP110和PCM蛋白Cep215和PCNT相互作用，促进 这些调节蛋白作为囊状货物重新分布到纺锤体中体。2.)审问 EHD1及其胞内相互作用伙伴调控纤毛发生的机制。我们将测试 假设EHD1/Mical-L1/Retromer复合体协调导致纤毛发生的步骤。影响： 了解这些过程的机制可以在内吞和转运之间建立新的联系。 中心体生物学，并将指导未来的研究，以探索中心体功能障碍的病因学 肿瘤发生和纤毛病变。

Centrosomes are microtubule nucleating and organizing organelles that directly affect the interphase microtubule array, mitotic spindles and cilia. Despite their significance in development and linkage to diseases such as cancer, ciliopathies and birth defects, fundamental aspects of centrosome function and duplication remain poorly understood. For example, some proteins within the organelle act as barriers to its duplication while others inhibit the assembly of cilia, and, thus, must be eliminated at specific points in the cell cycle to enable the step-wise progression of these events. At present, it is assumed that diffusion accounts for the exchange of most centrosomal proteins. However, trafficking of centrosomal proteins toward or away from centrosomes is a plausible but relatively unexplored mechanism for controlling centrosome duplication and ciliogenesis. Previously, we showed that the endocytic regulatory protein, EHD1, is a regulator of ciliogenesis by mediating the fusion of distal appendage vesicles on centrosomes to form the ciliary vesicle. Our data support an additional role for EHD1 in controlling the centrosome duplication cycle, by promoting the redistribution of Cep215, CP110 and pericentrin (PCNT) from centrosomes to the spindle midbody during mitosis, effectively removing these protein barriers of centrosome duplication. Our findings also implicate several EHD1-interacting partners, including the retromer and MICAL-L1. Remarkably, we now find that MICAL-L1 is anchored to the centrosome/centrioles by binding to tubulins, highlighting the possibility that it may serve as a recruiter of EHD1 to the centrosome. The objective of this application is to determine whether vesicular trafficking is a novel fundamental regulator of the centrosome duplication cycle and cilia formation. Our central hypothesis is that the EHD1/MICAL-L1/retromer recycling complex promotes a vesicular transport mechanism to strip specific regulatory proteins from centrosomes, thereby enabling key steps in centrosome duplication and ciliogenesis. Our specific aims are: 1.) Elucidate the mechanism by which endocytic vesicles remove centriolar and PCM proteins from centrosomes. We hypothesize that EHD1 (present of the cytoplasmic face of endocytic vesicles) docks with the distal appendages of centrioles, potentially via MICAL-L1, interacts with centriolar protein CP110 and PCM proteins Cep215 and PCNT, and facilitates the redistribution of these regulatory proteins to the spindle midbody as vesicular cargo. 2.) Interrogate the mechanisms by which EHD1 and its endocytic interaction partners regulate ciliogenesis. We will test the hypothesis that a EHD1/MICAL-L1/retromer complex coordinate the steps leading to ciliogenesis. Impact: Understanding the mechanisms of these processes forges a novel link between endocytic trafficking and centrosome biology, and will guide future studies to explore the etiology of centrosome dysfunction during tumorigenesis and ciliopathy.