RUI: The role of mitotic trafficking in cell fate specification

在发育中的胚胎中，一个细胞变成的组织类型主要取决于每个细胞从其邻居那里接收到的信号。 这些相同的信号也调节成年组织中功能齐全的细胞的行为。 细胞信号传导的缺陷是许多出生缺陷的原因，也可能导致癌细胞形成。 虽然在理解细胞信号传导的分子基础方面已经取得了很大的进步，但大多数工作都是在不分裂的细胞中进行的。 细胞分裂对细胞对信号反应的影响仍然知之甚少。 该项目将通过研究细胞分裂和信号之间的相互作用来填补这一关键空白。 拟议的实验将研究从邻近细胞接收信号的蛋白质如何在分裂细胞内移动。 由于癌细胞和胚胎细胞都经常分裂，这些信号接收蛋白在细胞分裂过程中的分布可能在创造胚胎细胞身份和促进癌细胞行为方面发挥关键作用。这项建议还将促进对不同的本科研究人员进行设计和开展独立研究项目的强化培训。 该项目还将通过与费城地区许多成熟的外展计划的互动来促进公众教育。技术段落：细胞命运诱导受信号成分贩运的影响。 最近的研究推翻了长期以来的假设，即膜运输在有丝分裂期间关闭。 因此，有丝分裂运输的信号成分可能发挥了深刻的，很大程度上未被认识到的作用，在细胞命运的规范。 PI的长期目标是了解细胞分裂如何影响感应信号处理。 这个问题是通过检查心脏祖细胞诱导的基础脊索动物，玻璃海鞘。 PI利用玻璃海鞘胚胎的极端细胞简单性来进行诱导信号传导机制的高分辨率体内分析，并专注于心脏祖细胞谱系的成纤维细胞生长因子（FGF）依赖性诱导。 FGF受体（FGFRs）的有丝分裂再分布被发现促进差异心脏祖细胞诱导。 PI假设有丝分裂激酶调节富含FGFR的粘附结构域的运输，并将通过以下具体目的来检验该假设：1）通过活的完整胚胎中标记蛋白的图像分析来表征富含FGFR的信号传导结构域的有丝分裂运输; 2）通过共定位分析使用通路-内吞通路描绘特异性内吞通路在信号传导结构域再分布中的作用。3）确定有丝分裂激酶如何通过激酶活性的靶向破坏来影响富含FGFR的结构域的内吞运输。 完成拟议的研究将提供关于胚胎和干细胞中分裂和信号传导之间相互作用的基本见解。

Non-Technical Paragraph:In developing embryos, the type of tissue that a cell becomes is primarily determined by signals each cell receives from its neighbors. These same signals also regulate the behavior of fully functional cells in adult tissues. Defects in cell signaling are the cause of many birth defects and can also cause cancer cells to form. Although great strides have been made in understanding the molecular basis of cell signaling, most of this work has been conducted in cells that are not dividing. The effect of cell division on cell response to signals remains poorly understood. This project will help fill this crucial gap by examining the interplay between cell division and signaling. The proposed experiments will examine how proteins that receive signals from neighboring cells are moved around inside dividing cells. Because both cancer cells and embryonic cells frequently divide, the distribution of these signal-receiver proteins during cell division is likely to play a crucial role in creating embryonic cell identity and in promoting cancerous cell behaviors. This proposal will also promote intensive training of diverse undergraduate researchers in designing and carrying out independent research projects. The project will also promote public education through interactions with many well-established outreach programs in the Philadelphia area.Technical Paragraph:Cell fate induction is affected by trafficking of signal components. Recent studies have overturned the long-held assumption that membrane trafficking is shut down during mitosis. Thus, mitotic trafficking of signaling components may play a profound, largely unrecognized role in cell fate specification. The long-term goal of the PI is to understand how cell division affects inductive signal processing. This question is addressed by examining heart progenitor induction in the basal chordate, Ciona intestinalis. The PI has exploited the extreme cellular simplicity of Ciona embryos to perform high-resolution, in vivo analysis of inductive signaling mechanisms, and focuses on Fibroblast Growth Factor (FGF)-dependent induction of the heart progenitor lineage. Mitotic redistribution of FGF receptors (FGFRs) was found to promote differential heart progenitor induction. The PI hypothesizes that mitotic kinases regulate trafficking of FGFR-enriched adherent domains, and will test this hypothesis through the following specific aims: 1) Characterization of mitotic trafficking of FGFR-enriched signaling domains through image analysis of tagged proteins in live, intact embryos; 2) Delineation of the role of specific endocytic pathways in signaling domain redistribution through co-localization analysis using pathway-specific markers and targeted disruption of pathway-specific components; 3) Determination of how mitotic kinases affect endocytic trafficking of FGFR-enriched domains through targeted disruption of kinase activity. Completion of the proposed studies will provide fundamental insights regarding the interplay between division and signaling in both embryonic and stem cells.