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
LPS-regulated SNAREs And Control Of Cytokine Secretion In Macrophages.
Funder
National Health and Medical Research Council
Funding Amount
$470,750.00
Summary
TNF(tumour necrosis factor alpha) is a potent proinflammatory cytokine secreted by immune activated macrophages. TNF has essential roles in host defense, tumour killing and energy metabolism. Excessive secretion of TNF in acute and chronic inflammatory conditions, such as septic shock, Crohn s disease, rheumatoid arthritis and in cancer has many severe, even fatal, consequences. Improved anti-TNF therapeutics are needed for clinical management in all of these conditions. Our studies are focused ....TNF(tumour necrosis factor alpha) is a potent proinflammatory cytokine secreted by immune activated macrophages. TNF has essential roles in host defense, tumour killing and energy metabolism. Excessive secretion of TNF in acute and chronic inflammatory conditions, such as septic shock, Crohn s disease, rheumatoid arthritis and in cancer has many severe, even fatal, consequences. Improved anti-TNF therapeutics are needed for clinical management in all of these conditions. Our studies are focused on investigating how macrophages synthesize and secrete TNF, with the ultimate goal of characterizing the molecules and vesicles in the TNF secretory pathway. Our recent findings show the expression of SNARE proteins, part of the vesicle docking and fusion machinery, is regulated in concert with cytokine secretion and other trafficking changes in activated macrophages. We identified the proteins Syntaxin4, Munc-18c and SNAP-23 as the specific t-SNARE complex that regulates TNF delivery to the cell surface. In the proposed studies we will investigate how SNAREs are regulated during macrophage activation by studying their gene expression and protein modifications. We have developed a single-cell assay to measure TNF trafficking in macrophages; this allows the identification of molecules with roles in TNF secretion and it will be used in a series of experiments to identify the specific v-SNARE proteins that partner the t-SNARE for TNF delivery. Finally we will use live cell imaging to investigate how and where TNF is delivered to the macrophage cell surface and membrane fractionation to examine a role for membrane microdomains in organizing SNARE-mediated TNF secretion. Manipulation of SNAREs, using data generated by these studies, holds potential for the development of new anti-TNF therapies.Read moreRead less
The Role Of Plasma Membrane Microdomains In Regulating Ras-dependent Raf Activation
Funder
National Health and Medical Research Council
Funding Amount
$216,100.00
Summary
In human cancers one or more of the signaling pathways leading from growth factor receptors at the cell surface to the nucleus where cell division is initiated are subverted. For example, a protein called Ras, that regulates a series of major signaling pathways, is mutated in 25% of all human tumours. This leaves Ras and the signaling pathways permanently switched on causing uncontrolled cell proliferation. Our previous work has demonstrated that Ras must be attached to the inner surface of the ....In human cancers one or more of the signaling pathways leading from growth factor receptors at the cell surface to the nucleus where cell division is initiated are subverted. For example, a protein called Ras, that regulates a series of major signaling pathways, is mutated in 25% of all human tumours. This leaves Ras and the signaling pathways permanently switched on causing uncontrolled cell proliferation. Our previous work has demonstrated that Ras must be attached to the inner surface of the cell membrane in order to function properly. This project now seeks to understand exactly how Ras attaches to and interacts with specific sites in the plasma membrane. Its is becoming clear that different isoforms of Ras, called H-, N- and K-ras have different functions in the cell which may in turn result from their different sites of attachment to the cell membrane. This is important because by understanding the precise micro-environment in which the different Ras proteins operate and how they activate subsequent proteins in their signaling networks we will be in a good position to design drugs that selectively compromise the function of each specific Ras isoform. A highly relevant example is provided by K-ras which is mutated in 90% of all pancreatic cancers and 50% of all colon cancers. Clearly the clinical impact of a drug that could selectively neutralise K-Ras function in these tumours is potentially enormous.Read moreRead less
Myofibroblast differentiation: from haemopoietic cells to smooth muscle. Until very recently the ability of adult cells with specific differentiated functions to re-differentiate for another function was thought to be extremely limited. However we have shown that cells ultimately derived from the bone marrow can differentiate into fibroblasts, then into myofibroblasts and then into smooth muscle cells. This project will build on these unique findings and determine the molecular mechanisms cont ....Myofibroblast differentiation: from haemopoietic cells to smooth muscle. Until very recently the ability of adult cells with specific differentiated functions to re-differentiate for another function was thought to be extremely limited. However we have shown that cells ultimately derived from the bone marrow can differentiate into fibroblasts, then into myofibroblasts and then into smooth muscle cells. This project will build on these unique findings and determine the molecular mechanisms controlling this process. We hypothesise that the local environment of a cell is critical and will involve a combination of particular extracellular matrix and growth factors as well as mechanical tension and the presence of other cell types.Read moreRead less
Factors involved in release of cytochrome c from mitochondria during apoptosis. Mitochondria are energy-producing organelles that activate cell death by selective release of constituents, notably cytochrome c, which participate in death-signalling cascades. I aim to probe such mitochondrial release mechanisms in intact cells, by focussing on features of translocated proteins relevant to release. Cultured mouse cells lacking cytochrome c are uniquely suited to these studies. A series of cytochrom ....Factors involved in release of cytochrome c from mitochondria during apoptosis. Mitochondria are energy-producing organelles that activate cell death by selective release of constituents, notably cytochrome c, which participate in death-signalling cascades. I aim to probe such mitochondrial release mechanisms in intact cells, by focussing on features of translocated proteins relevant to release. Cultured mouse cells lacking cytochrome c are uniquely suited to these studies. A series of cytochrome c derivatives will be engineered in elongated or aggregated forms and their release studied (including interactions with putative release machinery components) following death-signal activation. The project will elucidate a central mechanism in the cell death process, highly significant in many biological contexts.Read moreRead less
Identification of Proteins that Regulate Apoptosis Through Interaction With IAPS. Apoptosis is the process by which multicellular organisms eliminate unwanted cells. Identifying proteins involved in cell death regulation is central to our understanding of disease states arising from aberrations in this process. The mammalian protein DIABLO, promotes cell death by interacting with and antagonising inhibitor of apoptosis proteins (IAPS). Given the existence of several IAP regulatory proteins (IRPs ....Identification of Proteins that Regulate Apoptosis Through Interaction With IAPS. Apoptosis is the process by which multicellular organisms eliminate unwanted cells. Identifying proteins involved in cell death regulation is central to our understanding of disease states arising from aberrations in this process. The mammalian protein DIABLO, promotes cell death by interacting with and antagonising inhibitor of apoptosis proteins (IAPS). Given the existence of several IAP regulatory proteins (IRPs) in insects, other mammalian IRPs probably also exist. These may be of equal importance in regulating apoptosis, especially in tissues where DIABLO is not expressed. The main aim of the proposed study is to idenitify and characterise other IRPs in mammalian cells.Read moreRead less
Linkage Infrastructure, Equipment And Facilities - Grant ID: LE0226463
Funder
Australian Research Council
Funding Amount
$160,000.00
Summary
Fluorescence Lifetime Imaging Facility. The aim of this proposal is to establish the first fluorescence lifetime imaging facility (FLIM) in Australia. The imaging technique provided by the new facility when combined with the use of novel fluorescent protein technology will enable many different events, represented by protein-protein interactions, to be non-invasively, visualised spatially and temporally inside the living cell. The new facility will provide timely state-of -the-art infrastructu ....Fluorescence Lifetime Imaging Facility. The aim of this proposal is to establish the first fluorescence lifetime imaging facility (FLIM) in Australia. The imaging technique provided by the new facility when combined with the use of novel fluorescent protein technology will enable many different events, represented by protein-protein interactions, to be non-invasively, visualised spatially and temporally inside the living cell. The new facility will provide timely state-of -the-art infrastructure necessary for research groups to further develop and maintain their international reputations, will build stronger research collaborations between partner institutions and will attract researchers from overseas.Read moreRead less
Combined genetic and cellular analysis of melanisation to study variation in human pigmentation. This investigation examines variations in the genes that are important determinants of human skin pigmentation and are likely to be associated with skin cancer risk. Our research program will form the basis of future diagnostics based on major genes that determine a persons skin type. Current skin cancer prevention strategies rely predominantly on broad spectrum campaigns that are aimed at increasi ....Combined genetic and cellular analysis of melanisation to study variation in human pigmentation. This investigation examines variations in the genes that are important determinants of human skin pigmentation and are likely to be associated with skin cancer risk. Our research program will form the basis of future diagnostics based on major genes that determine a persons skin type. Current skin cancer prevention strategies rely predominantly on broad spectrum campaigns that are aimed at increasing the general community awareness of the damaging effects of UV radiation. A better understanding of the genetic basis of UV-sensitive skin types will greatly enhance the targeting of such skin cancer-prevention campaigns, provide an understanding of changes that occur in skin pathology, and the mechanisms of sun induced tanning.Read moreRead less