Mechanism Of Action Of Sec1p-like Proteins In Membrane Trafficking
Funder
National Health and Medical Research Council
Funding Amount
$234,936.00
Summary
One of the most important evolutionary changes that has occurred is the development of intracellular compartments. All eukaryotic cells possess numerous membrane-encased structures which provide the basis for intracellular specialisation. For example, in order to degrade unwanted components cells have developed degradative enzymes. It is vital for the cell that these enzymes are sequestered away from other cellular components to avoid destruction of valuable molecules. In addition, the cell has ....One of the most important evolutionary changes that has occurred is the development of intracellular compartments. All eukaryotic cells possess numerous membrane-encased structures which provide the basis for intracellular specialisation. For example, in order to degrade unwanted components cells have developed degradative enzymes. It is vital for the cell that these enzymes are sequestered away from other cellular components to avoid destruction of valuable molecules. In addition, the cell has developed a complex assembly line of modifications that are added to proteins in a specific order as they travel to their final destination within the cell. This necessitates the accurate passage of molecules between compartments, a process known as vesicle transport. To orchestrate the complex network of vesicular transport steps between all of the various intracellular compartments it is necessary to employ complex machinery to guide and check that these steps occur with high fidelity. The goal of our research proposal is to define the function of one of the molecules involved in this control process, the so-called Sec1p proteins. The strength of our proposal lies in the diversity of our approach. We intend to explore the molecular advantages of a relatively simple eukaryotic organism, a yeast cell, and apply the findings obtained from this cell to a more complex but highly related vesicular transport process; that of the insulin-regulated movement of a glucose transporter in mammalian fat and muscle cells. While we intend to apply our findings to the treatment of patients with diabetes, it is our ultimate goal to be able to learn more about this fundamental cell biological process so that we can apply our knowledge to understanding many different disease states.Read moreRead less
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