Antagonistic interaction of polarity complex proteins in cortical development

皮质发育中极性复合蛋白的拮抗相互作用

基本信息

批准号：
10386814
负责人：
Seonhee Kim
金额：
$ 34.67万
依托单位：
TEMPLE UNIV OF THE COMMONWEALTH
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-04-01 至 2025-03-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10386814
关键词：
Actomyosin Adherens Junction Apical Architecture Binding Cell Cycle Cell Cycle Progression Cell Polarity Cell division Cells Complex Cortical Malformation Defect Development Disease Epithelial Equilibrium Generations Genes Genetic Models Goals Hippocampus (Brain)Intellectual functioning disability Intercellular Junctions Lead Link Mediating Mediator of activation protein Microcephaly Molecular Mutant Strains Mice Myosin ATPase Neonatal Neurodevelopmental Disorder Neuroepithelial Neurofibromin 2 Neurologic Symptoms Neuronal Differentiation Neurons Output PARD6A gene Pathogenesis Pathway interactions Pharmacology Problem Solving Production Regulation Regulatory Pathway Research Side Signal Transduction Structure Testing Tight Junctions Time Transcription Coactivator antagonist insight migration mutant nerve stem cell neuroepithelium neurogenesis novel periventricular heterotopia prevent progenitor protein complex restoration stem stem cells

项目摘要

The overall goal of this proposal is to elucidate the mechanisms underlying the developmental defects leading to cortical malformation by characterizing the fundamental antagonistic interactions between evolutionarily conserved polarity complex proteins. Disruption of neuroepithelial structure causes abnormalities in neuronal outputs and cortical malformation that lead to a spectrum of neurodevelopmental disorders, including periventricular heterotopia (PH), microcephaly and ventriculomegaly. Asymmetrically distributed polarity protein complexes are critical for establishing and maintaining polarized cellular architecture and for determining unequal cell fate. Two complexes (Crb/Pals1/Patj and Mupp1; Par3/Par6/aPKC), termed apical polarity complex proteins, are localized at the apical side and one basal polarity complex (Lgl/DLG/Scb) is located basolaterally. Despite its critical importance for cortical epithelial structure and progenitor cell division, it is unclear whether a well-balanced interaction between them is required for cortical structure and neurogenesis, and the cellular and molecular machinery that mediates their functional interaction is also poorly understood. To identify their essential functional interactions and the underlying molecular mechanisms, we have generated a cortical-specific Llgl1 mutant characterized by massive PH and a cortical-specific Crb2 mutant with ventriculomegaly. Remarkably, Crb1/2 loss drastically reduces heterotopia in the Llg1 mutant. It has previously been shown that Llgl1 binds to myosin and regulates its activity, and that apical polarity complex proteins aPKC and Crb2 can inhibit myosin activity. Importantly, because cellular tension and junction defects are associated with the activation of mitogenic signals such as Yap/Taz transcription coactivator, downstream effectors of the Hippo pathway, this antagonism may also be linked to abnormal proliferation that produces the enlarged heterotopic cortex found in Llgl1 CKO. These observations lead us to hypothesize that the antagonistic interaction between basal and apical polarity complexes is required to establish/localize actomyosin at the apical junction and prevent activation of an abnormal Yap/Taz- dependent mitogenic signal. To test this hypothesis, in Aim1 we will define the antagonistic relationship between apical and basal complexes in cortical progenitor proliferation and junctional integrity by analyzing mutant mice. In Aim2 we will delineate the mechanism(s) by which polarity complex proteins regulate junctional integrity by investigating the antagonistic regulation of actomyosin. Lastly, in Aim3 we will determine whether Yap-Taz regulate mitogenic signaling after polarity disruption. Our study will increase understanding of polarity complex protein interactions in cortical progenitor cell division, which will provide new insights into the pathogenesis of cortical malformation and ultimately a basis for novel treatments.

该提案的总体目标是阐明导致发育缺陷的潜在机制通过表征进化之间的基本拮抗相互作用来治疗皮质畸形保守极性复合蛋白。神经上皮结构的破坏导致神经元异常输出和皮质畸形导致一系列神经发育障碍，包括脑室周围异位（PH）、小头畸形和脑室扩大。极性分布不对称蛋白质复合物对于建立和维持极化细胞结构以及决定不平等的细胞命运。两个复合体（Crb/Pals1/Patj 和 Mupp1；Par3/Par6/aPKC），称为顶端极性复合体蛋白，位于顶端侧，并且一种基础极性复合体（Lgl/DLG/Scb）是位于基底外侧。尽管它对于皮质上皮结构和祖细胞分裂至关重要，目前还不清楚皮质结构和皮质结构是否需要它们之间良好平衡的相互作用。神经发生以及介导其功能相互作用的细胞和分子机制也很差明白了。为了确定它们的基本功能相互作用和潜在的分子机制，我们产生了一种皮质特异性 Llgl1 突变体，其特征是大量 PH 和皮质特异性 Crb2 伴有脑室扩大的突变体。值得注意的是，Crb1/2 的缺失大大减少了 Llg1 突变体中的异位。它先前已证明 Llgl1 与肌球蛋白结合并调节其活性，并且顶端极性复合蛋白aPKC和Crb2可以抑制肌球蛋白活性。重要的是，因为细胞张力和连接缺陷与有丝分裂信号的激活有关，例如 Yap/Taz 转录共激活因子， Hippo 通路的下游效应子，这种拮抗作用也可能与异常增殖有关，产生 Llgl1 CKO 中发现的扩大的异位皮层。这些观察结果使我们推测需要基础极性复合物和顶端极性复合物之间的拮抗相互作用在顶端连接处建立/定位肌动球蛋白并防止异常 Yap/Taz 的激活依赖性有丝分裂信号。为了检验这个假设，在 Aim1 中我们将定义对抗关系通过分析顶部和基底复合物在皮质祖细胞增殖和连接完整性中的关系突变小鼠。在 Aim2 中，我们将描述极性复合蛋白调节连接的机制通过研究肌动球蛋白的拮抗调节来完整性。最后，在 Aim3 中我们将确定是否 Yap-Taz 在极性破坏后调节有丝分裂信号。我们的研究将增加对极性的理解皮质祖细胞分裂中复杂的蛋白质相互作用，这将为了解皮质畸形的发病机制，并最终为新疗法奠定基础。