Cellular Interactions in Patterning and Morphogenesis

细胞在模式形成和形态发生中的相互作用

• 批准号: 7988387
• 负责人: VICTOR HATINI
• 金额: $ 34.6万
• 依托单位: TUFTS UNIVERSITY BOSTON
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7988387
• 关键词: 1,2-diacylglycerol; Actins; Actomyosin; Adherence; Adhesives; Agreement; Apical; Back; Binding; Biological Assay; Biological Metamorphosis; Biosensor; Biotinylation; Cell membrane; Cell-Cell Adhesion; Cells; Development; Developmental Process; Diffuse Pattern; Diglycerides; Drosophila genus; Endosomes; Enzymes; Epithelial; Event; Fluorescence; Genes; Goals; Grant; Homologous Gene; In Situ Hybridization; Insecta; Joints; Leg; Light; Logic; Mediating; Microfilaments; Morphogenesis; Pathway interactions; Pattern; Phenotype; Process; Proteins; Recovery; Recycling; Retrieval; Role; Route; Site; Surface; System; Testing; Up-Regulation; Vertebrates; basolateral membrane; constriction; follow-up; gastrulation; loss of function; novel; p50rhoGAP; public health relevance; research study; rho GTP-Binding Proteins; trafficking

DESCRIPTION (provided by applicant): Apical constriction is an ancient developmental process that triggers key morphogenetic events such as neurulation in vertebrates and gastrulation in insects. However, the pathways involved are not fully understood. During pupariation, presumptive leg joints undergo apical constriction and epithelial invagination to initiate joint morphogenesis. We hypothesize that the process is mediated by an increase in actomyosin contractility and a decrease in cell-cell adhesion. The goal of this grant is to study the roles of the Rho GTPases Rho1, Rac1 and Cdc42 and their regulators, the RhoGEFs and RhoGAPs, in controlling the stability and turnover of adherence junctions (AJs), and the contribution of these genes to apical constriction and epithelial invagination during joint morphogenesis. We find that the inhibition of Rho1 or the activation of Rac1 or Cdc42 blocks joint morphogenesis. We also find that RhoGAP68F (GAP68F), a putative GAP for Cdc42, and RhoGAP5A (GAP5A), a putative GAP for Rac1, are expressed at presumptive joints and are required to initiate joint morphogenesis. We provide strong preliminary evidence to suggest that these regulators act through distinct pathways to control apical constriction. To test the role of the Rho GTPases and their regulators in apical constriction we propose the following specific AIMs: AIM1: We will test the hypothesis that Rho1, Cdc42 and Rac1 respectively regulate the influx, efflux and the stable pool of AJs at the ZA to promote apical constriction. AIM2: Large-scale interaction screens identified Rab4 and Sec3 as partners of GAP68F suggesting that GAP68F inhibits endocytic recycling from two distinct recycling routes to decrease the surface expression of AJs and thereby adhesive cell-cell contacts. In agreement, we find accumulation of GAP68F in the endocytic compartment. Therefore, we will test the hypothesis that GAP68F inhibits endocytic recycling and thereby adhesive cell-cell contacts to promote apical constriction. AIM3: We find that GAP5A is enriched at or near the zonula adherence (ZA). We will test the hypothesis that GAP5A acts at the ZA to decrease the stability of AJs and thereby adhesive cell-cell contacts to promote apical constriction. The successful completion of these studies will highlight the contribution of junctional stability and endocytic trafficking to apical constriction and epithelial invagination with implications to vertebrate systems. PUBLIC HEALTH RELEVANCE: The successful completion of the AIMs will help explain how the activities of the small RhoGTPases Rho1, Rac1 and Cdc42 are coordinated during development to control epithelial morphogenesis, and how the RhoGEFs and RhoGAPs regulate the activities of the RhoGTPases in topographically distinct subcellular sites to trigger changes in epithelial topology. Apical constriction is an evolutionarily conserved process and therefore these studies will have direct implications to vertebrate systems.

描述（由申请人提供）：顶部收缩是一个古老的发育过程，它会触发关键的形态发生事件，例如脊椎动物的神经性事件和昆虫的胃肠道。但是，涉及的途径尚未完全理解。在pupariation期间，推定的腿关节会经历顶端收缩和上皮内在，以引发关节形态发生。我们假设该过程是由肌动球蛋白收缩力增加和细胞粘附下降介导的。这笔赠款的目的是研究Rho GTPases Rho1，Rac1和Cdc42及其调节剂Rhogefs和Rhogaps的作用，在控制依从性连接（AJS）的稳定性和周转方面，以及这些基因对基因的狭窄和上皮开发过程的贡献。我们发现抑制Rho1或Rac1或Cdc42的激活阻断了关节形态发生。我们还发现，rhoGAP68F（GAP68F），一种用于CDC42的假定差距，Rhogap5a（GAP5A）是RAC1的假定差距，在推定关节上表达，需要启动关节形态发生。我们提供了有力的初步证据，以表明这些调节剂通过控制顶部收缩的不同途径作用。为了测试Rho GTPases及其调节剂在顶端收缩中的作用，我们提出了以下特定目的：AIM1：我们将测试Rho1，Cdc42和Rac1分别调节ZA上AJS的涌入，外排和稳定的AJ库的假设，以促进基本收缩。 AIM2：大规模相互作用屏幕将RAB4和SEC3鉴定为GAP68F的伙伴，这表明GAP68F抑制了两种不同的回收路线的内吞回收，以降低AJ的表面表达，从而降低粘合剂细胞细胞接触。总体而言，我们发现GAP68F在内吞区室中的积累。因此，我们将检验以下假设：GAP68F抑制内吞回收，从而抑制粘合细胞 - 细胞接触以促进顶端收缩。 AIM3：我们发现GAP5A在Zonula粘附（ZA）附近富集。我们将检验以下假设：GAP5A在ZA上起作用以降低AJ的稳定性，从而降低粘合剂细胞 - 细胞接触以促进顶端收缩。这些研究的成功完成将突出结合稳定性和内吞运输对顶端收缩和上皮内部的贡献，对脊椎动物系统的影响。 公共卫生相关性：成功完成目标将有助于解释小rhogtpases Rho1，Rac1和cdc42的活动如何在开发过程中协调以控制上皮形态发生，以及Rhogefs和Rhogaps如何调节rhogtpass在地形上不同的亚细胞位点中的Rhogtpass的活动，从而在上皮层次上触发上皮的拓扑结构。根尖的狭窄是一个进化保守的过程，因此这些研究将对脊椎动物系统产生直接影响。