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Mechanisms of basement membrane secretion and assembly

基底膜分泌和组装机制

基本信息

批准号：
10352423
负责人：
Sally Horne-Badovinac
金额：
$ 31.92万
依托单位：
UNIVERSITY OF CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-04-01 至 2023-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10352423
关键词：
Apical Architecture Basement membrane Binding Biochemical Biological Assay Biology Bulla Cell surface Cells Cytoplasm Data Defect Destinations Disease Drosophila genus Dystroglycan ECM receptor Ensure Epithelial Epithelial Cells Extracellular Matrix Genetic Goals Golgi Apparatus Gossypium Heart Homeostasis Image Kidney Diseases Kinesin Lateral Lead Location Logic Lung Mammary gland Mechanics Membrane Protein Traffic Membrane Proteins Molecular Monomeric GTP-Binding Proteins Morphogenesis Motion Motor Neoplasm Metastasis Organ Pathway interactions Play Proteins Research Role Salivary Glands Shapes Signal Transduction Site Skin Stroke Surface System Testing Three-Dimensional Imaging Tissue constructs Tissues Travel Tubular formation Variant Vesicle Vision Work biophysical techniques cell motility density egg imaging approach mechanical force membrane assembly migration network architecture novel programs recruit tool trafficking

项目摘要

PROJECT SUMMARY / ABSTRACT Basement membranes (BM) are specialized extracellular matrices found at the basal surface of all epithelial tissues. These sheet-like protein networks provide mechanical stability to the cells, promote cell-cell and cell- matrix signaling, and act as a physical barrier to metastasis. Moreover, defects in BM assembly lead to skin blistering, vision problems, nephropathy, and stroke. Some aspects of BM assembly are shared by all epithelia. For example, when new BM proteins are made by the epithelial cells, post-Golgi vesicles filled with BM proteins (BM vesicles) must be trafficked exclusively to basal cellular regions for secretion. Other aspects of BM assembly are tissue-specific. For example, local variations in BM composition and density direct the branching of the mammary gland, salivary gland and lung. However, despite their clear importance to epithelial biology, we know remarkably little about how BMs are built. The goals of this proposal are: (1) to identify the molecular logic underlying polarized BM secretion, and (2) to determine how the basic BM assembly program can be modified to create a specialized BM architecture for organ morphogenesis. To this end, we are studying the BM that surrounds the Drosophila egg chamber (the multi-cellular precursor to the egg). The epithelial cells that form the egg chamber’s outer layer (follicle cells) secrete their own BM that is easily visualized on the egg chamber’s surface. We and others previously used this system to identify two small GTPases, Rab10 and Rab8, that act as master regulators of polarized BM secretion. However, how these Rabs direct the transport of BM vesicles from their point of origin at the Golgi to the basal- most region of the cell where the BM needs to be assembled is unknown. We have identified two kinesins that, when depleted, cause BM proteins to be mis-secreted. In Aim 1, we will test the hypothesis that Rab10 and/or Rab8 recruit the kinesins to BM vesicles for directed transport. This work will identify fundamental mechanisms that determine where and how a BM is built and identify new guiding principles for polarized membrane traffic. The BM we study also has a specialized architecture that allows it to act as a “molecular corset” to elongate the egg chamber. The follicle cells collectively migrate along their BM, which remains stationary. We showed that this motion synergizes with new BM secretion to build an oriented array of fibrils into the planar BM that form the heart of the molecular corset. This work has now led us to hypothesize that there may be two BM secretion pathways, a Rab10-dependent pathway that builds the planar BM and a Rab8-dependent pathway that builds the fibrils. Aim 2 will test this hypothesis. Our supporting data further suggest that BM proteins that exit the cell via the fibril-forming pathway must be placed under tension by the migrating cells for linear fibrils to form. Aim 3 will test this hypothesis. By studying these two tissue-specific mechanisms for BM formation, we will identify general principles that cells can use to build a specialized BM architecture for organ morphogenesis and identify a new role for mechanical forces in BM assembly.

项目摘要/摘要