Regulation of apical constriction of bottle cells by the RhoGEF protein Plekhg5 during gastrulation morphogenesis

原肠胚形态发生过程中 RhoGEF 蛋白 Plekhg5 对瓶细胞顶端收缩的调节

• 批准号: 10359811
• 负责人: CHENBEI CHANG
• 金额: $ 32.17万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-03-01 至 2025-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10359811
• 关键词: Actins; Activins; Actomyosin; Address; Adhesions; Adult; Affect; Apical; Architecture; Behavior; Binding; Biochemical; Blastopores; Cadherins; Cell Adhesion; Cell Adhesion Molecules; Cell Shape; Cell physiology; Cell surface; Cells; Complex; Cytoskeleton; Data; Defect; Development; Developmental Biology; Disease; Ectoderm; Embryo; Embryonic Development; Epithelial; Epithelial Cells; Etiology; Event; F-Actin; Failure; Geometry; Goals; Grant; Guanine Nucleotide Exchange Factors; Human; Investigation; Knowledge; Lip structure; Membrane; Molecular; Molecular Analysis; Morphogenesis; Myosin ATPase; Neural Tube Closure; Neural Tube Defects; Organ; PLEKHG5 gene; Pathway interactions; Phospholipids; Process; Proteins; Regulation; Research; Role; Sensory; Shapes; Signal Transduction; Structure; Surface; Testing; Time; Tissues; Tubular formation; Vertebrates; Xenopus; apical membrane; base; constriction; gastrulation; human disease; insight; knock-down; member; movie; prevent; recruit; rho; rho GTPase-activating protein; wound healing

Apical constriction is a cell shape change that associates with cell ingression, bending of epithelial sheet, and formation of tubular structures. It is found in many morphogenetic processes, such as gastrulation, neural tube closure, and sensory organ formation. Failure in apical constriction can cause human congenital diseases, such as neural tube defects. Despite the importance of apical constriction in multiple developmental contexts, molecular regulators of apical constriction are not understood completely. Rho signaling has been implicated previously in apical constriction during vertebrate neural tube closure and sensory placode invagination. However, general activation of Rho throughout a cell does not lead to apical constriction, underscoring that polarized stimulation of Rho within particular subcellular compartment is crucial. Spatial regulation of Rho activities is normally achieved by Rho regulators GEFs and GAPs. Over 20 members each of RhoGEFs and RhoGAPs perform diverse cellular functions. The identity of Rho regulators in apical constriction in vertebrates is not well defined, and the mechanisms via which Rho regulators act to control cell shape changes are not described in detail. This knowledge gap, combined with the importance of apical constriction in embryogenesis, demands further investigation about molecular machinery controlling apical constriction. In our current study, we identified plekhg5 as a RhoGEF expressed in the bottle cells of the blastopore lip during Xenopus gastrulation and had a function in regulating apical constriction of the bottle cells. Plekhg5 protein is apically localized and stimulates apical actomyosin assembly to induce ectopic blastopore lip in a Rho-dependent fashion when ectopically expressed. Knockdown of plekhg5 blocks apical constriction of bottle cells at the blastopore lip and prevents activin from inducing blastopore lip in the ectoderm. Plekhg5 is thus an endogenous RhoGEF in bottle cells that participates in regulation of apical constriction during gastrulation. The activity of plekhg5 provides us an excellent opportunity to address some of the key issues regarding apical constriction in any tissue contexts, namely how Rho regulators are recruited to particular subcellular compartment(s) to exert their function (aim 1); how they modulate dynamic actomyosin organization to coordinate reduction of apical cell surface and adhesion complex remodeling (aim 2); and how different downstream effectors are involved in regulating distinct aspects of actomyosin dynamics and cell shape changes (aim 3). Completion of the proposed studies will offer us deeper insight into molecular control of apical constriction and provide us a platform to investigate and compare molecular mechanisms governing apical constriction in diverse tissue contexts. The results may also contribute to our understanding of human diseases caused by abnormal epithelial morphogenesis due to defects in apical constriction.

顶部收缩是一种细胞形状的变化，与细胞的融合，上皮的弯曲相关联 薄板和管状结构的形成。它在许多形态发生过程中发现，例如 胃结构，神经管闭合和感觉器官形成。顶部收缩的失败可以 引起人类先天性疾病，例如神经管缺陷。尽管根尖很重要 在多种发育环境中的收缩，顶部收缩的分子调节因子不是 完全理解。 RHO信号传导先前涉及到顶端收缩 脊椎动物神经管闭合和感觉置换座不知所措。但是，RHO的一般激活 在整个细胞中不会导致顶端收缩，强调了对Rho的极化刺激 在特定的亚细胞室内至关重要。 RHO活动的空间调节通常是 由Rho调节器GEF和GAPS实现。超过20名Rhogefs和Rhogaps的成员 执行各种细胞功能。 Rho调节剂在脊椎动物中的顶部收缩中的身份 定义不当，Rho调节器控制细胞形状的机制变化的机制 未详细描述。这种知识差距，结合了根尖收缩的重要性 在胚胎发生中，需要进一步研究控制顶端的分子机械 收缩。在当前的研究中，我们确定了plekhg5为在 异武胃期间的胚孔唇，并在调节顶端收缩方面起作用 瓶单元。 plekhg5蛋白是顶端局部的，并刺激顶端肌动球蛋白组装到 当异位表达时，以Rho依赖性的方式诱导异位胚型唇。击倒 plekhg5阻止胚嘴唇部瓶细胞的顶部收缩，并防止激活素 在外胚层诱导胚孔唇。因此 参与胃结构期间顶端收缩的调节。 Plekhg5的活动为我们提供了 解决有关任何组织中根尖收缩的一些关键问题的绝佳机会 上下文，即如何招募Rho调节剂到特定的亚细胞室以发挥作用 它们的功能（AIM 1）；他们如何调节动态肌动球蛋白组织以协调还原 顶端细胞表面和粘附复合物重塑（AIM 2）；以及下游的不同 效应子参与调节肌球蛋白动力学和细胞形状变化的不同方面 （目标3）。拟议研究的完成将为我们提供对顶端分子控制的更深入的了解 收缩并为我们提供一个平台来调查和比较分子机制 在各种组织环境中的根尖收缩。结果也可能有助于我们对 由于根尖收缩缺陷，由异常上皮形态发生引起的人类疾病。