Functional Characterisation Of N4WBP5 And N4WBP5A, Novel Nedd4-interacting Proteins
Funder
National Health and Medical Research Council
Funding Amount
$480,750.00
Summary
The proteins that make up a cell must be correctly localised in order to perform their normal function. Specialised cellular activities are carried out in distinct compartments within a cell and proteins must correctly localise in them and traffic between them. Intracellular protein trafficking is a highly regulated process involving many components. Recent findings have shown that intracellular trafficking is regulated in many cases by distinct protein modifications. One such modification is ta ....The proteins that make up a cell must be correctly localised in order to perform their normal function. Specialised cellular activities are carried out in distinct compartments within a cell and proteins must correctly localise in them and traffic between them. Intracellular protein trafficking is a highly regulated process involving many components. Recent findings have shown that intracellular trafficking is regulated in many cases by distinct protein modifications. One such modification is tagging of a small protein called ubiquitin to proteins that are being trafficked. A focus of research in our laboratory is the study of a protein, called Nedd4, which directly tags proteins with ubiquitin. We have recently identified two novel proteins that interact with Nedd4 and localise to distinct subcellular compartments that are sites for the correct sorting and delivery of proteins trafficking within the cell. The main aim of our proposal is to characterise how these proteins function. We propose that these proteins are involved in intracellular trafficking and that they may function by targeting Nedd4 to the cellular trafficking machinery. This may be required for Nedd4 to tag molecules with ubiquitin that are involved in intracellular trafficking. Our experiments will test the functional relationship between Nedd4 and the novel proteins and determine the particular trafficking pathways in which these proteins are involved. Defects in cellular processes regulated by Nedd4 and other similar proteins cause a number of human diseases including an inherited form of hypertension and a specific group of cancers. In addition, a large number of human diseases result directly from defects which disrupt intracellular trafficking pathways. The results of this study will provide further insight into this essential cellular process and may ultimately contribute to the development of therapies for diseases resulting from defects in intracellular trafficking.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
Tumor Specific Variants Of The EGFR: Characterization, Function And Target For Immunotherapy.
Funder
National Health and Medical Research Council
Funding Amount
$140,880.00
Summary
Antibodies are a major component of the bodies immune system that bind (i.e. stick) to foreign substances such as viruses. Once bound, these antibodies can activate other parts of the immune system, which help destroy the foreign substance. Analogous to the situation above, a number of institutions are testing antibodies that bind to cancer cells, in order to determine if they are able to destroy these cells. This therapeutic approach requires an antibody that specifically binds to cancer cells ....Antibodies are a major component of the bodies immune system that bind (i.e. stick) to foreign substances such as viruses. Once bound, these antibodies can activate other parts of the immune system, which help destroy the foreign substance. Analogous to the situation above, a number of institutions are testing antibodies that bind to cancer cells, in order to determine if they are able to destroy these cells. This therapeutic approach requires an antibody that specifically binds to cancer cells but not normal cells. In this proposal, we wish to test a novel antibody that binds to a protein on the cell surface called the EGF receptor. While the EGF receptor is found on the surface on many cells, our antibody recognizes a modified version of the EGF receptor that is found exclusively on cancer cells. Previous EGF receptor antibodies tested in the clinic all recognized the normal EGF receptor and thus proved unsuitable as they bound to cells in the liver causing significant side effects. It is anticipated that the specificity of our novel antibodies will overcome this problem. Eventually this antibody could be used to treat patients with brain, breast, prostate and lung cancer. We will also conduct a number of studies to determine the function of this modified receptor. This work will improve our understanding of those events associated with development of tumors.Read moreRead less
Fluorescence Analysis Of The EGFreceptor Signalling Network
Funder
National Health and Medical Research Council
Funding Amount
$490,750.00
Summary
Receptors are cell-surface molecules that enable the cell to receive chemical messages from the outside environment and transmit these signals to the inside of cell. These messages tell the cells to grow, divide or die. The Epidermal Growth Factor Receptor is linked to a variety of cell signalling pathways that are critical to the normal functioning of cells. Conversely, abberations in Epidermal Growth Factor-mediated cell signalling leads to many types of cancers. A basic understanding of how t ....Receptors are cell-surface molecules that enable the cell to receive chemical messages from the outside environment and transmit these signals to the inside of cell. These messages tell the cells to grow, divide or die. The Epidermal Growth Factor Receptor is linked to a variety of cell signalling pathways that are critical to the normal functioning of cells. Conversely, abberations in Epidermal Growth Factor-mediated cell signalling leads to many types of cancers. A basic understanding of how the receptor is turned off or on is essential to designing drugs that can specifically inhibit its hyperproliferative response. High resolution structures of a key part of the Epidermal Growth Factor Receptor have identified several structural forms of the receptor that are providing valuable clues as to the structural basis for receptor activation. Armed with this information and advanced microscopic imaging technology we are in the unique position to probe receptor activation in living cells. This project seeks to determine which structural form of the receptor is responsible for transmission of cellular messages and how it is impaired in cancerous cells.Read moreRead less
C-Kit Signalling And Cellular Responses In Haemopoietic Cells
Funder
National Health and Medical Research Council
Funding Amount
$731,115.00
Summary
Growth factors acting on cell surface receptors activate multiple intracellular signalling pathways that regulate cellular growth and function. Mutations in the genes that code for these receptors or their downstream signalling pathways contribute to many human cancers. The contributions of different signalling pathways linked to these receptors to the various cellular responses (growth, maturation, functional activation) are not understood. In this project we aim to use cell and molecular biolo ....Growth factors acting on cell surface receptors activate multiple intracellular signalling pathways that regulate cellular growth and function. Mutations in the genes that code for these receptors or their downstream signalling pathways contribute to many human cancers. The contributions of different signalling pathways linked to these receptors to the various cellular responses (growth, maturation, functional activation) are not understood. In this project we aim to use cell and molecular biology approaches to determine the role of different signalling pathways in cellular responses mediated by the growth factor receptor c-Kit. The c-Kit receptor has essential functions in blood cell development, skin and hair pigmentation, gut function and the reproductive system. It is also essential for the development and function of mast cells which trigger allergic responses such as asthma and eczema. Mutant forms of the receptor have been identified in certain leukaemias and colon cancers. Many new drugs that target specific intracellular signalling pathways have recently been developed and are beginning to be evaluated in clinical trials. Better understanding of how individual pathways contribute to the function of c-Kit and other receptors is essential for optimal use of these new drugs. For example, it may enable the choice of drugs to block c-Kit dependent cancer cell growth or allergic reactions without affecting the growth of normal blood cells.Read moreRead less