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.
Recycling Endosomes Governing Cell Polarity And Cytokine Secretion.
Funder
National Health and Medical Research Council
Funding Amount
$958,412.00
Summary
Cytokines are chemical messengers released by cells to mount inflammatory responses to fight infections. The timing and direction of cytokine release must be tightly regulated. We investigate the cellular compartments and molecules that control cytokine secretion using sophisticated live cell imaging. Uncontrolled cytokine release is the main cause of ongoing inflammation in arthritis and inflammatory bowel disease and our studies aim to identify cellular targets for new drug development.
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
Ras Signalling And Cholesterol Efflux From Late Endosomes
Funder
National Health and Medical Research Council
Funding Amount
$276,598.00
Summary
Accumulation of cholesterol is a hallmark of early atherosclerotic lesions, known as foam cell formation. Hence the stimulation of cholesterol removal (efflux) from macrophages has great therapeutic potential. High Density Lipoproteins (HDL) and apolipoprotein A-I (apoA-I) stimulate efflux via activation of HDL-apoA-I receptors and poorly understood signalling pathways. This application is investigating the role of the Ras-MAPK signalling pathway in promoting efflux from late endosomes.
Molecular Determinants Of Subcellular Localisation And Function Of The Transmembrane 4 Superfamily Protein, PETA-3
Funder
National Health and Medical Research Council
Funding Amount
$322,911.00
Summary
Several years ago we identified the cell membrane protein PETA-3-CD151 based on its ability to cause activation of blood platelets, suggesting a role in thrombosis. More recently we found that the protein is present in a variety of tissues, although its distribution in those tissues is often restricted. It is abundant in a variety of cancer cells, and is present on tissue mast cells that mediate allergic reactions. PETA-3-CD151 forms complexes with molecules (integrins) that are associated with ....Several years ago we identified the cell membrane protein PETA-3-CD151 based on its ability to cause activation of blood platelets, suggesting a role in thrombosis. More recently we found that the protein is present in a variety of tissues, although its distribution in those tissues is often restricted. It is abundant in a variety of cancer cells, and is present on tissue mast cells that mediate allergic reactions. PETA-3-CD151 forms complexes with molecules (integrins) that are associated with cell adhesion and migration, and antibodies to this protein inhibit cell movement. Thus PETA-3-CD151 appears to be involved in cellular interactions that are critical for normal tissue development and function, and may be involved in several disease processes including cancer invasion and metastasis. The molecular basis of PETA-3-CD151 function is not understood and is the focus of this application.Read moreRead less
Inside our cells is a complex traffic system. The vehicles are vesicles that come in different shapes and sizes and travel to specific destinations in the cell to deliver cargo such as: surface growth factor receptors that are to have their signalling terminated, proteins and lipids destined for the cell wall for growth or development (like neurite outgrowth) and proteins and hormones destined for secretion (like neurotransmitter release). More than 100 human genetic disorders map to defects in ....Inside our cells is a complex traffic system. The vehicles are vesicles that come in different shapes and sizes and travel to specific destinations in the cell to deliver cargo such as: surface growth factor receptors that are to have their signalling terminated, proteins and lipids destined for the cell wall for growth or development (like neurite outgrowth) and proteins and hormones destined for secretion (like neurotransmitter release). More than 100 human genetic disorders map to defects in one of the components of this system. Proteins called small GTPases provide order for this traffic and allow specific cargo to reach specific destinations. They regulate cell functions by acting as switches, turning biochemical processes on and off inside the cell. Ral is a small GTPase enzyme found in brain and broadly distributed in other cells. We have discovered that Ral is part of a large signalling complex. When activated Ral stimulates effectors, either the exocyst or RalBP1. In turn, mild oxidative stress controls a Ral inhibitor protein called ERp57. The research proposed aims to establish the functional role for the Ral signalling complex in cells. We will determine with which vesicle trafficking events Ral is associated, which effector it utilises in that pathway, and how that effector directs the traffic. We will also map the steps that may lead to inactivation of Ral via ERp57 in cells, and propose that this is mediated by mild oxidative stress. Techniques of molecular biology, biochemistry, molecular biology, proteomics and microscopy will be used to establish these functions. The research will lead to increased knowledge of the significance of this protein to cellular and particularly neuronal cell function. This forms the basis for understanding normal cell function and for identification of further factors causing diseases of vesicle transport. In time, such research aids in the development of specific therapies for sufferers of such diseases.Read moreRead less
Genetic Approaches To Understand How Imbalanced Cytokine Signalling Drives The Pathogenesis Of Emphysema
Funder
National Health and Medical Research Council
Funding Amount
$519,715.00
Summary
Emphysema is a major component of Chronic Obstructive Pulmonary Disease (COPD), the fifth leading cause of death in Australia for which there is no effective treatment. We have discovered a specific mutation in a gene called gp130 that results in the formation of emphysema in mice. This finding allows us to understand the exact mechanisms by which this mutation causes emphysema, and therefore has the potential to uncover new strategies to design novel therapies against emphysema in humans.
Cross-talk Between Cytokine And Pathogen Recognition Receptor Networks In The Pathogenesis Of Gastric Cancer
Funder
National Health and Medical Research Council
Funding Amount
$174,800.00
Summary
Stomach cancer is the second most common cause of cancer-related deaths worldwide, and results in the yearly death of several thousand people in Australia alone. We have discovered a specific mutation in a gene called gp130 that results in the formation of gastritis and stomach cancer in mice. We are now aiming to understand the exact molecular events by which this mutation results in chronic inflammation and the subsequent uncontrolled growth of epithelial cells that line the stomach wall.