Molecular Interactions Of The Tetraspanins CD37, TSSC6 And CD151 In T Cells
Funder
National Health and Medical Research Council
Funding Amount
$566,575.00
Summary
The tetraspanins are a new type of protein that are found at the surface of cells. Cells of the immune system, such as white blood cells, display at their surface, up to 20 different tetraspanin proteins. However, the precise contributions of these tetraspanin proteins to immunity is still not clear, nor is it clear exactly how tetraspanin proteins differ from one another and why white blood cells need to display so many different tetraspanins. Using genetic technology we have created mice which ....The tetraspanins are a new type of protein that are found at the surface of cells. Cells of the immune system, such as white blood cells, display at their surface, up to 20 different tetraspanin proteins. However, the precise contributions of these tetraspanin proteins to immunity is still not clear, nor is it clear exactly how tetraspanin proteins differ from one another and why white blood cells need to display so many different tetraspanins. Using genetic technology we have created mice which are unable to express certain individual tetraspanin proteins at their cell surface. Excitingly, the immune systems of these mice are not normal, in particular one type of white blood cell, the T cell responds in an exaggerated manner to stimulation. These results suggest a role for tetraspanins in the control and regulation of the immune system. This project will extend these results and work out the precise molecular mechanism by which the tetraspanins exert this control. In the future, a full understanding of how tetraspanins control T cells may ultimately lead to novel ways of controlling the immune system.Read moreRead less
Characterisation Of The Molecular Mechanisms Of Abeta-induced Proteolysis Of The Neural Cell Adhesion Molecule 2 (NCAM2)
Funder
National Health and Medical Research Council
Funding Amount
$374,666.00
Summary
Neurons in the brain are connected by synaptic contacts. Amyloid beta peptide accumulating in the brain in Alzheimer’s disease destroys synaptic contacts by degrading synaptic cell adhesion molecules which maintain the structure of the contacts. The aim of the project is to characterise the molecular mechanisms of amyloid beta-dependent degradation of synaptic cell adhesion molecules. The project will identify strategies that can be used to inhibit synapse loss in Alzheimer’s disease.
Identifying An Autism Gene Network Governing Stem Cell Division, Neurogenesis And Cortical Malformation
Funder
National Health and Medical Research Council
Funding Amount
$1,003,589.00
Summary
Failure to produce neural stem cells and new neurons in the embryonic cortex results in cortical malformations and autism, and thus has profound consequences for the individual's survival and quality of life. Here we explore how a unique network of autism proteins maintains stem cell activity and neuronal production, thereby ensuring the fidelity of cortical development.
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
How The Dosage Of A Down Syndrome Candidate Gene Affects Neural Circuitry And Behaviour
Funder
National Health and Medical Research Council
Funding Amount
$414,961.00
Summary
In Down syndrome, an extra copy of chromosome 21 increases gene expression and leads to brain defects. We hypothesise that one candidate gene, Dscam2, changes its function with increased expression. This causes brain cells that normally stick to each other to repel each other, leading to inappropriate connections in the brain. We will test this model in the fruit fly and demonstrate for the first time a mechanism dependent on gene expression that can lead to brain abnormalities in Down syndrome.
Dendritic cells are a very rare type of white blood cell which play a critical role in the initiation of the immune response. They are of particular interest to scientists interested in vaccination, as for a vaccine to work effectively, the vaccine must be presented to the rest of the immune system by the dendritic cell. It has only recently become apparent that there are several types of dendritic cell, and these different types of dendritic cell vary in their ability to present a vaccine to th ....Dendritic cells are a very rare type of white blood cell which play a critical role in the initiation of the immune response. They are of particular interest to scientists interested in vaccination, as for a vaccine to work effectively, the vaccine must be presented to the rest of the immune system by the dendritic cell. It has only recently become apparent that there are several types of dendritic cell, and these different types of dendritic cell vary in their ability to present a vaccine to the immune system. We have already identified some proteins that are expressed on the surface of only one type of dendritic cell. We will explore the possible use of these proteins as a means of delivering a vaccine to only one type of dendritic cell. This project will also identify new genes that are expressed in some types of dendritic cells but not others. These new genes whose expression does differ amongst the dendritic cells are potential targets for manipulating the immune system and ensuring more efficient vaccination.Read moreRead less
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
Targeting The Hypoxia Sensing Pathway To Improve Hematopoietic Stem Cell Mobilisation And Transplantation
Funder
National Health and Medical Research Council
Funding Amount
$653,313.00
Summary
Transplantation of patients’ own blood stem cells is used to treat many blood cancers. It increases the chance of cure. However the damage caused by chemotherapies used to combat the cancer can compromise stem cell collection and transplantation. Without transplant, these patients are less likely to survive cancer. This project is to test new drugs that enhance the harvest of blood stem cells for transplantation. These will increase the success rates of transplants and cure in these cancer patie ....Transplantation of patients’ own blood stem cells is used to treat many blood cancers. It increases the chance of cure. However the damage caused by chemotherapies used to combat the cancer can compromise stem cell collection and transplantation. Without transplant, these patients are less likely to survive cancer. This project is to test new drugs that enhance the harvest of blood stem cells for transplantation. These will increase the success rates of transplants and cure in these cancer patients.Read moreRead less