Polarized Trafficking Of E-cadherin In Epithelial Cells.
Funder
National Health and Medical Research Council
Funding Amount
$515,564.00
Summary
The cell adhesion protein E-cadherin is expressed in all epithelial tissues of the body where it has essential functions during development and in the adult in establishing and maintaining polarized cell monolayers. E-cadherin is also a vital tumour suppressor, its normal function guarantees that cells or even early tumours cannot metastasise; in contrast E-cadherin is always lost or malfunctions in malignant tumours. Earlier studies showed that E-cadherin is constantly moved, or trafficked, to ....The cell adhesion protein E-cadherin is expressed in all epithelial tissues of the body where it has essential functions during development and in the adult in establishing and maintaining polarized cell monolayers. E-cadherin is also a vital tumour suppressor, its normal function guarantees that cells or even early tumours cannot metastasise; in contrast E-cadherin is always lost or malfunctions in malignant tumours. Earlier studies showed that E-cadherin is constantly moved, or trafficked, to and from the surface of epithelial cells. This trafficking has dual roles, firstly in delivering newly-made E-cadherin to the surface where it functions and secondly, in regulating its adhesive function. Our research in this project is focussed on the molecules and intracellular compartments that control the delivery of E-cadherin to the cell surface. E-cadherin must be sorted in order to be delivered to the correct side of the cell. Having previously discovered the sorting signal in E-cadherin, we will now identify the cognate adaptor protein(s) that accomplish this sorting. New imaging techniques allow us to study protein trafficking inside live cells. Such studies have recently revealed that E-cadherin passes through a recycling endosome compartment on its way to the cell surface. This unexpected route, and the structure and role of the recycling endosome will now be studied in detail in live cells. Finally we will compare the sorting and trafficking of E-cadherin with the closely-related N-cadherin protein, to determine whether there are inherent differences in their trafficking that could explain their opposite roles in tumour cells, where N-cadherin is substituted for E-cadherin and allows metastatic behaviour. These studies will provide important information for understanding the adhesive and tumour suppressive roles of E-cadherin. In addition our findings will generate information fundamental to our understanding of cell polarity and protein sorting.Read moreRead less
PrtFII, A Streptococcus Pyogenes Fibronectin Binding Protein, And Invasive Diseases.
Funder
National Health and Medical Research Council
Funding Amount
$296,540.00
Summary
Our recent work revealed that, in the Aboriginal population, young age is a risk factor for severe invasive diseases caused by group A streptococcus. For group A streptococcus infection to occur, bacterial attachment is the first step. The bacterium attaches to host cells through interactions involving host fibronectin and the pathogen's fibronectin-binding proteins. We have found that streptococcal strains from severe disease cases are more likely to have the gene for PrtFII, a fibronectin bind ....Our recent work revealed that, in the Aboriginal population, young age is a risk factor for severe invasive diseases caused by group A streptococcus. For group A streptococcus infection to occur, bacterial attachment is the first step. The bacterium attaches to host cells through interactions involving host fibronectin and the pathogen's fibronectin-binding proteins. We have found that streptococcal strains from severe disease cases are more likely to have the gene for PrtFII, a fibronectin binding protein, than those from uncomplicated skin sores. In this application we propose to extend this observation and compare biochemical properties of PrtFII from strains belonging to the above two sets of collections. We hypothesise that PrtFII from invasive strains bind to fibronectin more tightly than the proteins from strains that cause uncomplicated infection. We also will test whether sera from invasive disease cases have lower titre of antibodies to the conserved region of PrtFII than sera from uncomplicated cases. A streptococcal vaccine by necessity has to be a multi-component vaccine to cover a wide spectrum of diseases and epidemiological differences. The study proposed here may provide a basis to argue whether or not to include PrtFII in such a multi-component vaccine.Read moreRead less
Control of actin assembly by cell-cell adhesion: molecular effectors and higher order function. Functional cooperation between the actin cytoskeleton and cadherin cell-cell adhesion molecules plays critical roles during development and morphogenesis. This proposal builds on my lab's recent discovery that E-cadherin interacts with and regulates the Arp2/3 actin nucleator complex, a central determinant of actin assembly in cells. We will explore key implications of this finding, concentrating on d ....Control of actin assembly by cell-cell adhesion: molecular effectors and higher order function. Functional cooperation between the actin cytoskeleton and cadherin cell-cell adhesion molecules plays critical roles during development and morphogenesis. This proposal builds on my lab's recent discovery that E-cadherin interacts with and regulates the Arp2/3 actin nucleator complex, a central determinant of actin assembly in cells. We will explore key implications of this finding, concentrating on defining the molecular mechanisms that regulate Arp2/3 and actin assembly in cadherin-based adhesion. Our work combines molecular characterization of regulatory mechanisms and proteomic searches for new regulators, with tests of the higher-order function of this novel process in cell adhesion and recognition.Read moreRead less
Balancing cadherin-actin cooperation: the key regulatory role of Ena/VASP proteins. This project analyses a fundamental mechanism of how cells work together in tissues. Understanding the fundamental mechanisms of how cells work will provide important basic scientific information to enrich the scientific expertise in Australia and its part in the international community, generate insights relevant for understanding human disease and physical degeneration, and support the training of young scienti ....Balancing cadherin-actin cooperation: the key regulatory role of Ena/VASP proteins. This project analyses a fundamental mechanism of how cells work together in tissues. Understanding the fundamental mechanisms of how cells work will provide important basic scientific information to enrich the scientific expertise in Australia and its part in the international community, generate insights relevant for understanding human disease and physical degeneration, and support the training of young scientists in Australia.Read moreRead less
E-Cadherin Endocytosis In Morphogenesis: Recycling And Growth Factor Induced Uptake.
Funder
National Health and Medical Research Council
Funding Amount
$498,088.00
Summary
E-cadherin is a cell-cell adhesion protein expressed in all epithelia with essential roles in establishing cell polarity and in tissue patterning during development. In the adult, E-cadherin functions to maintain epithelial integrity. E-cadherin is also a vital tumour suppressor, protecting cells against metastatic transformation. Our earlier studies showed that E-cadherin is constantly moved, or trafficked, to and from the surface of epithelial cells. The endocytosis or internalisation of cell ....E-cadherin is a cell-cell adhesion protein expressed in all epithelia with essential roles in establishing cell polarity and in tissue patterning during development. In the adult, E-cadherin functions to maintain epithelial integrity. E-cadherin is also a vital tumour suppressor, protecting cells against metastatic transformation. Our earlier studies showed that E-cadherin is constantly moved, or trafficked, to and from the surface of epithelial cells. The endocytosis or internalisation of cell surface E-cadherin serves to regulate its role in adhesion. More recently, we and others have shown that E-cadherin is endocytosed in response to growth factors, in conjunction with the activated growth factor receptors themselves. E-cadherin can influence the trafficking and signaling of these receptor tyrosine kinases. This joint endocytosis is an elegant mechanism for the simultaneous downregulation of cell adhesion and activation of signaling for cell growth and motility. The growth and differentiation of epithelial cells during tissue patterning or morphogenesis relies critically on these endocytic pathways. Our research is aimed at defining the endosomes and cellular machinery involved in E-cadherin-receptor endocytosis, moreover we will pursue initial findings suggesting that there are different pathways and fates for E-cadherin endocytosed at the behest of different growth factors. We will study endocytosis during the processes of epithelial cyst formation and tubulation of cysts as an in vitro model for mammalian morphogenesis. These studies will provide important and novel information for understanding the roles of E-cadherin in adhesion and in growth factor signaling during epithelial morphogenesis. Ultimately these findings will be of relevance to epithelial development and the prevention of cancer.Read moreRead less
Discovery Early Career Researcher Award - Grant ID: DE210101144
Funder
Australian Research Council
Funding Amount
$429,450.00
Summary
Understanding crosstalks between Natural Killer cells and Dendritic Cells. This project aims to investigate the interactions between two populations of immune cells: natural killer cells and dendritic cells. This proposal will advance basic knowledge in immunology by innovating in considering the heterogeneity and diversity of these two immune populations and combining interdisciplinary approaches using cutting-edge technologies. Expected outcomes from this proposal include the identification of ....Understanding crosstalks between Natural Killer cells and Dendritic Cells. This project aims to investigate the interactions between two populations of immune cells: natural killer cells and dendritic cells. This proposal will advance basic knowledge in immunology by innovating in considering the heterogeneity and diversity of these two immune populations and combining interdisciplinary approaches using cutting-edge technologies. Expected outcomes from this proposal include the identification of new immunoregulatory pathways, the development of new scientific theories, and enhancement of Australia’s research capacity through international collaborations and student training. This project will provide significant benefits such as the identification of biological targets for development of new biotechnologies. Read moreRead less
Tissue tension homeostasis by junctional mechanosensing. This project examines how tissues use mechanical tension to preserve their integrity. This comes from the recent appreciation that cells pull on the connections between each other to generate tension. Further, molecular mechanisms exist for cells to sense changes in this tension and then to enlist the appropriate responses to restore tension. The project aims to test how local changes in tension are detected and corrected, when tissue inte ....Tissue tension homeostasis by junctional mechanosensing. This project examines how tissues use mechanical tension to preserve their integrity. This comes from the recent appreciation that cells pull on the connections between each other to generate tension. Further, molecular mechanisms exist for cells to sense changes in this tension and then to enlist the appropriate responses to restore tension. The project aims to test how local changes in tension are detected and corrected, when tissue integrity is compromised by very different causes. The project endeavours to establish a new conceptual paradigm for understanding tissue homeostasis, based on cell biology and biomechanics, with implications for developmental biology and tissue engineering.Read moreRead less
Understanding the molecular mechanisms regulating neuronal fusion. Neurons are tightly connected individual cells that communicate through chemical and electrical signals, and this project aims to discover the key molecules that allow these cells to remain as individual units without fusing with each other. The nervous system, unlike other tissues, is made of discrete individual cells, connected by chemical and electrical synapses but not by cytoplasmic continuity. However, how this is achieved ....Understanding the molecular mechanisms regulating neuronal fusion. Neurons are tightly connected individual cells that communicate through chemical and electrical signals, and this project aims to discover the key molecules that allow these cells to remain as individual units without fusing with each other. The nervous system, unlike other tissues, is made of discrete individual cells, connected by chemical and electrical synapses but not by cytoplasmic continuity. However, how this is achieved and how neurons maintain their individuality during development, remodelling and ageing is unknown. The project aims to address this gap using a genetic approach and the nematode Caenorhabditis elegans as an experimental system. The results may provide insights into how the nervous system develops and functions.Read moreRead less