The Role Of Membrane Condensation In T Lymphocyte Activation And Signal Transduction
Funder
National Health and Medical Research Council
Funding Amount
$82,421.00
Summary
T cell lymphocytes are essential cells in our immune system. They respond to signals from foreign bodies to mount an immune response. Many diseases arise from errors in their activation processes. The key steps in the translation of the initial arrival of a foreign-body to a T cell into an immune response will be examined in these studies, where we will look at the cooperation of components of the cell membrane during T cell activation. This will help us to understand and treat immune disorders.
Functional Characterization Of Caveolae And Caveolins
Funder
National Health and Medical Research Council
Funding Amount
$140,660.00
Summary
This project aims to study the cellular machinery that allows a cell to respond to its external environment. Specifically, this project focusses on the function of a family of membrane proteins, called caveolins, which are the major protein components of caveolae small pits which cover the surface of many mammalian cells. Caveolins are believed to regulate signalling from the external environment to the cell interior and loss of this regulation leads to uncontrolled growth leading to cancer. Sig ....This project aims to study the cellular machinery that allows a cell to respond to its external environment. Specifically, this project focusses on the function of a family of membrane proteins, called caveolins, which are the major protein components of caveolae small pits which cover the surface of many mammalian cells. Caveolins are believed to regulate signalling from the external environment to the cell interior and loss of this regulation leads to uncontrolled growth leading to cancer. Signalling from the cell surface relies on organisation of signalling components into modules. Our studies suggest that these modules are dependent on specific lipid molecules which form discrete patches, called lipid rafts, on the cell surface. We have hypothesised that caveolins control the lipid molecules associated with lipid rafts and so, indirectly, control signalling pathways. In particular, we have shown that caveolin is important in the regulation of cellular cholesterol, a vital molecule involved in maintaining the function of lipid raft domains. As numerous human diseases are associated with cholesterol imbalance, studies of caveolins can give fundamental new insights into this process, and the previously unidentified links between the cellular lipid balance and signal transduction. This project aims to use mutant caveolin molecules to disrupt caveolin function and so determine the role of caveolin in lipid regulation and in signal transduction. We will then use a lower vertebrate model system, which is amenable to experimental manipulation, to determine the role of caveolins and rafts in the development of the whole embryo.Read moreRead less
The Role Of The 72 KDa Inositol Polyphosphate 5-phosphatase In Cellular Function.
Funder
National Health and Medical Research Council
Funding Amount
$549,196.00
Summary
Cells respond to external signals and the environment to undergo cell growth, secretion and-or other specialized functions including control of cell death and-or cell size. We have identified a new enzyme (72kDa 5-phosphatase) which resides inside the cell and regulates signals generated by an enzyme called PI3-kinase. Two of the PI3-kinase signals have been demonstrated to regulate the activity of an oncogene involved in breast and ovarian cancer. We aim to determine the specific role each of t ....Cells respond to external signals and the environment to undergo cell growth, secretion and-or other specialized functions including control of cell death and-or cell size. We have identified a new enzyme (72kDa 5-phosphatase) which resides inside the cell and regulates signals generated by an enzyme called PI3-kinase. Two of the PI3-kinase signals have been demonstrated to regulate the activity of an oncogene involved in breast and ovarian cancer. We aim to determine the specific role each of these PI3-kinase signals plays in the activation of the oncogene. In addition the levels of the 72kDa enzyme is altered in some cervical and lymphoma cancers. We will image live cells containing specific fluorescent probes under different conditions and study the activation and location of these probes in order to understand how different PI3-kinase signals are regulated in time and space. In addition to regulating signals that are involved in cancer, PI3-kinase controls signals that are important for proper immune function. Phagocytosis is a biological process where specialised immune cells (macrophages) take up and remove harmful particles such as bacteria or tumour cells from the circulation. This process depends on PI3-kinase and the signals it produces. We will determine whether the 72 kDa enzyme, which is expressed in macrophages, plays a role in regulating these signals during phagocytosis. We have shown that the 72 kDa enzyme can interact with several different proteins which may affect its location and activity within the cell. We will examine the effect of these interactions on the PI3-kinase signals which are involved in cell survival and immune responses. We will study the function of the enzyme in the intact animal by producing mice which lack this enzyme. Given the possible role of this enzyme in cancer, these mice will be examined for their susceptibility to develop tumours.Read moreRead less
Elucidation Of The Molecular Requirements Of The Low Affinity 'state' Of The Beta1-adrenoceptor
Funder
National Health and Medical Research Council
Funding Amount
$535,500.00
Summary
Beta-blockers are used for the management of cardiovascular diseases including heart failure, ischaemic heart disease and high blood pressure. Beta-blockers mostly work by blocking the effects of a naturally occuring chemical called noradrenaline. Beta-blockers can be used to prevent noradrenaline induced increases in the rate and force of human heart contraction. We have discovered that one group of beta-blockers exemplified by CGP 12177 has the remarkable property of not only being able to blo ....Beta-blockers are used for the management of cardiovascular diseases including heart failure, ischaemic heart disease and high blood pressure. Beta-blockers mostly work by blocking the effects of a naturally occuring chemical called noradrenaline. Beta-blockers can be used to prevent noradrenaline induced increases in the rate and force of human heart contraction. We have discovered that one group of beta-blockers exemplified by CGP 12177 has the remarkable property of not only being able to block beta-receptors but they can also stimulate them at higher concentrations. Thus low concentrations block the effects of noradrenaline, but higher concentrations stimulate the receptor. More puzzling is that the stimulant effects of this group of beta-blockers cannot be easily blocked. To explain this we hypothesize that human beta-receptors can exist in two different 'states'. One 'state' can be stimulated by noradrenaline and blocked by low concentrations of beta-blockers such as propranolol and CGP 12177. Another 'state' of the same receptor is resistant to blockade by beta-blockers such as propranolol but can be stimulated by beta-blockers such as CGP 12177. This project seeks to investigate the molecular basis of the beta-adrenoceptor that is responsible for stimulant effects of beta-blockers. Specifically it explores the components of the beta-adrenoceptor that are critically and uniquely important for interacting with the stimulant beta-blockers. This project is an important increment in our laboratories research program to increase our understanding of the effects of beta-blockers. Our long term goal is to be able to develop beta-blockers that can block both states of the beta-adrenoceptor to provide a more effective block of the receptor and in particular for the improved management of heart failure.Read moreRead less
Molecular Attributes And Physiological Significance Of Beta1L-adrenoceptors
Funder
National Health and Medical Research Council
Funding Amount
$754,353.00
Summary
Beta-blockers are used for the management of cardiovascular diseases including heart failure. We have discovered that one group of beta-blockers not only blocks the receptor but stimulates it. To explain this we hypothesize that human beta-adrenoceptors exist in two different 'states' , high and low. We are now determining whether 1. the low state causes progression of heart failure, 2. the molecular basis of the two states and 3. we can make new compounds to block the low state.
The Role Of Ryk/AF6/Eph Complexes In Neuronal Pathfinding/fasciculation
Funder
National Health and Medical Research Council
Funding Amount
$422,036.00
Summary
During embryonic development nerve cells in the central nervous system have to find the right connections to make with other nerve cells. The process by which nerve cells find the right partners to make connections with is called neuronal pathfinding. Once some nerve cells have made the right connections, other nerve cells attach to these cells and form bundles of nerve fibres. This process is called fasciculation or bundling. This whole process is vital to the normal development and function of ....During embryonic development nerve cells in the central nervous system have to find the right connections to make with other nerve cells. The process by which nerve cells find the right partners to make connections with is called neuronal pathfinding. Once some nerve cells have made the right connections, other nerve cells attach to these cells and form bundles of nerve fibres. This process is called fasciculation or bundling. This whole process is vital to the normal development and function of the central nervous system and the brain. Without the right connections between nerves, information could not be received, processed or sent to organs in the body. We are now starting to discover some of the molecules which control the process of nerve cell pathfinding during development. It has been known for some time that proteins called Eph receptors play an important role in neuronal pathfinding and development of the head region in mice. We have now discovered that two other proteins called Ryk and AF-6 are able to bind to Eph receptors. We have very recently created mice which lack the Ryk protein and these mice have defects in their head deveopment strikingly similarto the head defects seen in mice that lack Eph receptors. We now wish to see whether Ryk mice have defects in neuronal pathfinding and fasciculation as do mice lacking Eph receptors. We also think that Ryk, Af-6 and Eph receptors form a protein complex which can modify cell function. We now wish to explore how this protein complex can do this.Read moreRead less
Loss Of Cytostatic Regulation By TGF-beta During EGFR-driven Tumor Development
Funder
National Health and Medical Research Council
Funding Amount
$605,031.00
Summary
Growth factor and cytokine signalling networks control many aspects of cell behaviour such as proliferation, survival, migration, invasive capabilities, transformation and differentiation. In normal cells, these complex signalling pathways are tightly regulated. Alterations of these signals are often found to cause, directly or indirectly, tumour formation. Transforming Growth Factor-b (TGF-b) and Epidermal Growth Factor (EGF) signalling pathways are both independently implicated as key regulato ....Growth factor and cytokine signalling networks control many aspects of cell behaviour such as proliferation, survival, migration, invasive capabilities, transformation and differentiation. In normal cells, these complex signalling pathways are tightly regulated. Alterations of these signals are often found to cause, directly or indirectly, tumour formation. Transforming Growth Factor-b (TGF-b) and Epidermal Growth Factor (EGF) signalling pathways are both independently implicated as key regulators in tumour formation and as such they are potential therapeutic targets. However, while both pathways have been studied extensively, little is known about the cross-talk between the TGF-b and EGF pathways. This project will establish the generality of a new tumor signaling axis, namely EGFR-Stat3-Smad7-TGF-b in EGFR-overexpressing tumors. Practically, it will provide guidelines for the development of new approaches for treating effectively the EGFR-driven tumors.Read moreRead less
Validation Of Stat3 As A Therapeutic Target In Diseases Arising From Its Inappropriate Activation By Gp130 Cytokines
Funder
National Health and Medical Research Council
Funding Amount
$674,142.00
Summary
Stomach cancer is the third most prevalent cancer in the Western World and result in the yearly death of several thousand people in Australia alone. We have discovered a specifice gene mutation of a receptor molecule called gp130 that results in the formation of stomach cancer in mice. We are now aiming to understand the exact molecular events by which this mutation results in the uncontrolled growth of stomach lining cells. We will employ a number of strategies to establish molecularly the exte ....Stomach cancer is the third most prevalent cancer in the Western World and result in the yearly death of several thousand people in Australia alone. We have discovered a specifice gene mutation of a receptor molecule called gp130 that results in the formation of stomach cancer in mice. We are now aiming to understand the exact molecular events by which this mutation results in the uncontrolled growth of stomach lining cells. We will employ a number of strategies to establish molecularly the extent to which this mouse model is informative for gastric cancer inhuman. In aprticular we will identify the genes that are involved in the progression of the disease. One important focus of the project is to see whether or not the moelcule (called Stat3) whose aberrant activation triggers the disease in the mouse could provide a future pharmacological target for intervention with the disease. Similarly with expertise of CIB, we will investigate with novel proteomics techniques whther we can identify a protein in the serum of these mice, which could give us aclue of whether or not the mouse ahs already developed disease. Such a protein could be of potentail diagnostic importance in the future to screen human for gastric cancer which in its eraly stages is usually without any clinical symptoms. In a related Aim we will find out the gene that can genetically cooperate with Stat3 and that is required to enable survival of newborn mice. It may well turn out mOur proposal combines the expertise of the two investigators in signal transduction and that this gene may be an important determinant to ensure that Stat3 triggers physiological rather than pathological responses in many differnet organs.Read moreRead less