The Interaction Between CD46 And PSD-95/Dlg-4: Roles In Cell Polarisation And CD46 Signalling.
Funder
National Health and Medical Research Council
Funding Amount
$70,000.00
Summary
Immune defence against pathogens is primarily achieved by the activities of a range of blood cells, including T cells. T cells have specialised functions involving direct killing of the pathogen, and recruitment and activation of other immune cells. Many of these functions require the lymphocyte to become polarised, or asymmetric, in order to concentrate the appropriate cellular machinery towards the site of activity. Examples of polarisation in lymphocytes includes (i) the formation of a single ....Immune defence against pathogens is primarily achieved by the activities of a range of blood cells, including T cells. T cells have specialised functions involving direct killing of the pathogen, and recruitment and activation of other immune cells. Many of these functions require the lymphocyte to become polarised, or asymmetric, in order to concentrate the appropriate cellular machinery towards the site of activity. Examples of polarisation in lymphocytes includes (i) the formation of a single protrusion, or uropod, that forms the basis for cell-cell interactions, (ii) the formation of an immune synapse which allows a T cell to recognise a pathogen, and (iii) the direction of the cellular killing machinery towards the target. The process of cell polarisation is best characterised in neurons and epithelial cells, both of which are asymmetric. In each cell type, a major mechanism of regulating polarisation is the expression and targeting of a family of proteins containing regions called PDZ domains. PDZ domains mediate protein-protein interactions and so allow the assembly of large molecular scaffolds which hold proteins in specific cell sites. The loss of cell polarity in some cells is thought to cause uncontrolled proliferation and tumour progression, and some of the PDZ-containing proteins are tumour suppressors. We have identified a PDZ-containing protein that is polarised in T cells, and have evidence that this protein interacts with and controls the polarisation of a cell surface receptor whose functions include the regulation of T cell function and proliferation. The aim of this proposal is to determine the mechanisms and functional consequences of polarisation of these two proteins in T cells, and to determine whether their interaction or polarisation is important for T cell proliferation.Read moreRead less
Immune defence against pathogens is primarily achieved by the activities of a range of blood cells, including T cells. T cells have specialised functions involving direct killing of the pathogen, and recruitment and activation of other immune cells. Many of these functions require the lymphocyte to become polarised, or asymmetric, in order to concentrate the appropriate cellular machinery towards the site of activity. Examples of polarisation in lymphocytes includes (i) the formation of a single ....Immune defence against pathogens is primarily achieved by the activities of a range of blood cells, including T cells. T cells have specialised functions involving direct killing of the pathogen, and recruitment and activation of other immune cells. Many of these functions require the lymphocyte to become polarised, or asymmetric, in order to concentrate the appropriate cellular machinery towards the site of activity. Examples of polarisation in lymphocytes includes (i) the formation of a single protrusion, or uropod, that forms the basis for cell-cell interactions, (ii) the formation of an immune synapse which allows a T cell to recognise a pathogen, and (iii) the direction of the cellular killing machinery towards the target. The process of cell polarisation is best characterised in neurons and epithelial cells, both of which are asymmetric. In each cell type, a major mechanism of regulating polarisation is the expression and targeting of a family of proteins containing regions called PDZ domains. PDZ domains mediate protein-protein interactions and so allow the assembly of large molecular scaffolds which hold proteins in specific cell sites. The loss of cell polarity in some cells is thought to cause uncontrolled proliferation and tumour progression, and some of the PDZ-containing proteins are tumour suppressors. We have identified a PDZ-containing protein that is polarised in T cells, and have evidence that this protein interacts with and controls the polarisation of a cell surface receptor whose functions include the regulation of T cell function and proliferation. The aim of this proposal is to determine the mechanisms and functional consequences of polarisation of these two proteins in T cells, and to determine whether their interaction or polarisation is important for T cell proliferation.Read moreRead less
Investigating The Physiological And Biochemical Role Of SOCS5 In The Immune System
Funder
National Health and Medical Research Council
Funding Amount
$405,940.00
Summary
Asthma affects millions of people worldwide and is a complex inflammatory disease of the lung. Asthma manifests as recurrent episodes of wheezing, breathlessness, chest tightening, and coughing. Three key proteins called; interleukin 4 (IL-4), interleukin 13 (IL-13) and interleukin 5 (IL-5) are produced by a subset of white blood cells (T helper cells; Th2) and are thought to be responsible for the asthma response. Normally these proteins act to coordinate the body s immune defence against paras ....Asthma affects millions of people worldwide and is a complex inflammatory disease of the lung. Asthma manifests as recurrent episodes of wheezing, breathlessness, chest tightening, and coughing. Three key proteins called; interleukin 4 (IL-4), interleukin 13 (IL-13) and interleukin 5 (IL-5) are produced by a subset of white blood cells (T helper cells; Th2) and are thought to be responsible for the asthma response. Normally these proteins act to coordinate the body s immune defence against parasite infection. In other words, asthma is thought to arise through inappropriate IL-4 and IL-13 activity in the absence of a parasite infection. Extra IL-13 is commonly found in the lungs of asthmatics and is thought to help trigger asthma attacks. IL-13 is a validated target for drugs that could be used in the treatment of asthma. The SOCS genes were discovered in our laboratory and by genetically deleting the genes in mice we have demonstrated a critical role for SOCS1, SOCS2 and SOCS3 in regulating the immune response and the action of growth hormone. My hypothesis is that SOCS5 is an important physiologic regulator of the asthma response. This proposal will investigate the basic biochemical processes underlying the regulation of IL-4 and IL-13 action and the relationship to development of asthma and immune disease. I plan to induce asthma attacks in mice that lack the genes for SOCS4 and SOCS5. If the severity of the attacks is greater in the absence of these proteins this will indicate that SOCS4 and-or SOCS5 are important negative regulators of IL-4 and IL-13. This has the potential to open up a completely new strategy for the development of drugs that could be used in the prevention and treatment of asthma.Read moreRead less
The regulated movement of membrane receptors and ligands between the cell surface and intracellular compartments is vital to many cellular operations, including communication between cells and their environment. However, the molecular details of these sorting events remain poorly defined. Determination of the mechanisms that control the cellular distribution of receptors is critical for understanding normal cellular processes and in pathological processes like tumorigenesis.
Structural Studies On Cell Signalling Via The LIF Receptor And Gp130
Funder
National Health and Medical Research Council
Funding Amount
$453,943.00
Summary
The cytokines play important roles in the immune system during blood cell development and inflammation, and in nerve growth, bone remodeling, reproduction and heart development. Cell responses are initiated by a cytokine bringing together on the cell surface a receptor complex made up of multiple molecules. This project will investigate the atomic structure of the cell surface macromolecular complex, and hence the underlying mechanism by which cytokine signals are initiated.
The Structural Basis Of Ligand-Induced Activation Of The Insulin Receptor
Funder
National Health and Medical Research Council
Funding Amount
$640,825.00
Summary
We aim to understand how insulin binds to and activates its cell-surface receptor. This information has implications for the design of anti-diabetic agents targetted directly to the insulin receptor. Diabetes is a global health problem and is classified by the World Health Organization as an epidemic. The results also have implications for the insulin-like growth factor receptor system and the design of anti-cancer therapeutics directed towards it .
The Interactions Of Dengue Virus RNA Dependent RNA Polymerase (NS5) With Other Viral And Host Factors.
Funder
National Health and Medical Research Council
Funding Amount
$170,165.00
Summary
Dengue fever is a mosquito-borne disease that is prevalent in tropical countries. It is estimated that 40% of the global population is at risk of dengue infection. Classical dengue fever is not life threatening. However, the more serious disease, dengue haemorrhagic fever-shock syndrome requires intensive medical attention to prevent fatality. A significant number of deaths are recorded each year especially in the underdeveloped countries. Dengue is periodically also a problem in northern Austra ....Dengue fever is a mosquito-borne disease that is prevalent in tropical countries. It is estimated that 40% of the global population is at risk of dengue infection. Classical dengue fever is not life threatening. However, the more serious disease, dengue haemorrhagic fever-shock syndrome requires intensive medical attention to prevent fatality. A significant number of deaths are recorded each year especially in the underdeveloped countries. Dengue is periodically also a problem in northern Australia. There is no cure for dengue fever. The present research aims to use a knowledge-based approach to develop novel antiviral strategies based on preventing the critical protein interactions required for the normal virus life cycle. Two of the most important proteins involved in dengue virus replication are called the NS3 and NS5 proteins. The protein-protein interaction (contact) that occurs between NS5 and NS3 is crucial for the replication of the virus. Little is known about this interaction at present, and the studies we propose will directly address this issue. We have previously shown that a 37 amino acid in the middle of NS5 contains a nuclear localisation signal that can target the normally cytoplasmic protein to the nucleus of the infected cell. What the function of this protein is in the nucleus is not known. We will use a technique called the yeast two-hybrid test to address the question of dengue virus protein interactions in the common bakers yeast. This method is very sensitive and powerful and will provide important insights that will contribute to the development of a rapid high-throughput test to screen the extensive extract collection from Australia's marine biodiversity, held by the Australian Institute of Marine Sciences, to discover suitable inhibitors of NS3-NS5 interaction.Read moreRead less
Sorting Nexins And Their Role In Endosomal Trafficking
Funder
National Health and Medical Research Council
Funding Amount
$331,000.00
Summary
Cells are able to internalise molecules via membrane-bound vesicles, a process known as endocytosis. Endocytosis is fundamental for many cellular processes, including receptor signalling, uptake of many essential nutrients and the ability to mount an effective lymphocyte response to foreign antigens. Once internalised, cargo is then sorted to different intracellular destinations of the endosomal transport system. The ultimate destination depends on the particular cargo molecule. The importance o ....Cells are able to internalise molecules via membrane-bound vesicles, a process known as endocytosis. Endocytosis is fundamental for many cellular processes, including receptor signalling, uptake of many essential nutrients and the ability to mount an effective lymphocyte response to foreign antigens. Once internalised, cargo is then sorted to different intracellular destinations of the endosomal transport system. The ultimate destination depends on the particular cargo molecule. The importance of the endosomal transport system is also highlighted by the discovery that many human diseases, including various cancers, lysosomal storage diseases and hypercholesterolemia, are linked to defects in trafficking along the endocytic pathway. Furthermore, a number of viral pathogens, such as HIV, and toxins, such as shiga toxin, exploit the endosomal system to gain entry into a cell. Understanding the molecular details of the sorting events within the endosomal system is necessary to be able to consider therapeutic manipulation of the trafficking of specific cargo molecules. The study seeks to understand the molecular details of the endosomal sorting machinery, knowledge that will underpin future efforts to develop drugs to manipulate movement of proteins within the endosomal system. In the long term, this could allow for the manipulation of a variety of cellular functions including the inhibition of proliferative signals in tumour cells.Read moreRead less
This established team of investigators will research into the molecular control of white blood cell formation and function, using a multidisciplinary, team approach to fundamental biological questions with a focus on potential clinical and commercial outcomes. The team will also attempt to identify new validated targets for therapeutic intervention by using both forward and reverse genetic approaches in mice coupled with complete phenotypic analyses of the blood cell system.