Leukaemia-cancer cells have altered biochemical properties resulting in their high rate of growth compared to normal cells. One of these is augmented activity of enzymes called tyrosine kinases including members of the Src family. One called Lyn has been implicated in several leukaemias as well as cancer. We have identified a novel mechanism of down-regulating this family of enzymes mediated by small proteins. These may allow us to develop novel therapeutics for cancer-leukaemia treatment.
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
Signalling Networks As Targets For Antibody Therapy In Glioma.
Funder
National Health and Medical Research Council
Funding Amount
$526,683.00
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. It is also possible to generate antibodies that bind to receptors on the surface of can ....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. It is also possible to generate antibodies that bind to receptors on the surface of cancer cells and block their function. If you target a receptor critical to the growth or survival of a cancer cell in this way, then swtiching-off this signal may inhibit tumor growth. In this proposal we plan to test a panel antibodies that recognize receptors important to the growth of brain cancer. Two of these antibodies have been generated and the other two will be made as part of this proposal. A key aspect of this proposal will be testing these antibodies in combination to determine how many receptors need to be targeted in order to get complete tumor regressions in animal models. Overall this work will help us identify new therapeutic strategies for the treatment of brain cancer. Finally, we will also analyze the way different receptors interact together in brain cancer cells.Read moreRead less
Mature red cells develop from hemopoietic stem cells in the adult bone marrow. The production of red blood cells is primarily controlled by the hormone erythropoietin (Epo). Previously we had identified that the protein Lyn must be present inside primitive red blood cells for Epo to stimulate them to become mature functional cells. We will determine the role of several molecules that interact with Lyn including Cbp, Liar and LACM, towards apects of red blood cell development.
Molecular Mechanisms Of Receptor Activation And Signalling
Funder
National Health and Medical Research Council
Funding Amount
$571,980.00
Summary
Fundamental to our ability to respond to both immediate and long-term environmental changes and stresses is the coordinated regulation of cellular functions by hormonal and neurotransmitter stimuli. The great majority of such stimuli are sensed by G-protein coupled receptors (GPCR), complex glycoprotein molecules on the surface of most cells that selectively bind and are activated by various hormones and neurotransmitters. Although GPCRs are a superfamily of proteins that now compromise several ....Fundamental to our ability to respond to both immediate and long-term environmental changes and stresses is the coordinated regulation of cellular functions by hormonal and neurotransmitter stimuli. The great majority of such stimuli are sensed by G-protein coupled receptors (GPCR), complex glycoprotein molecules on the surface of most cells that selectively bind and are activated by various hormones and neurotransmitters. Although GPCRs are a superfamily of proteins that now compromise several hundred distinct but structurally-related members, the molecular mechanisms involved in their activation and, thus, their regulation of vital cellular functions, remains unclear. Based on insights that we have gained from the development and characterisation of several alpha1-adrenergic receptor mutants, we have developed a model of receptor activation. In this application we are proposing to further test and to extend the hypotheses underlying this model. Importantly, the functions regulated by GPCR include vital responses, such as the maintenance of circulatory homeostasis by augmenting heart pump function and by constricting vascular smooth muscle to maintain blood pressure. In addition, disordered cellular regulation by GPCR has been implicated in a wide variety of diseases, including hypertension, congestive heart failure and cardiac hypertrophy. Thus, the studies detailed here to further understand the molecular mechanisms of receptor activation have broad implications for our knowledge of critical physiological control systems, and may lead to novel therapeutic approaches to treat a variety of diseases.Read moreRead less
Cytokine Signalling And Insulin Resistance In Obesity.
Funder
National Health and Medical Research Council
Funding Amount
$512,065.00
Summary
Western communities are experiencing an epidemic of obesity that is contributing to diabetes, heart disease, and premature death. This project is investigating why being overweight and obese causes diabetes. Improved understanding about how hormones regulates the body's storage and breakdown of fat and responsiveness to insulin will enable the development of new medicines for the treatment of obesity and the prevention of diabetes.
Impaired Bone Remodelling Leads To Failure Of Orthopaedic Prostheses
Funder
National Health and Medical Research Council
Funding Amount
$515,917.00
Summary
The failure of bone prostheses is becoming a major health problem. More than 26,000 hip, and an equal number of knee, replacements were performed in Australia in 2002 with the number increasing between 5%-10% each year for the previous 10 years. Disturbingly, the incidence of revision hip surgery in Australia is now more than 15%, meaning that, despite the impressive success of joint replacement surgery, a significant number of arthroplasties fail. It is becoming more common for young, active in ....The failure of bone prostheses is becoming a major health problem. More than 26,000 hip, and an equal number of knee, replacements were performed in Australia in 2002 with the number increasing between 5%-10% each year for the previous 10 years. Disturbingly, the incidence of revision hip surgery in Australia is now more than 15%, meaning that, despite the impressive success of joint replacement surgery, a significant number of arthroplasties fail. It is becoming more common for young, active individuals to receive joint replacement surgery to improve their quality of life. This, combined with increasing life expectancy, and the known higher rate of failure of joint replacements in younger patients, means that the morbidity of a failed replacement, and the mobidity and associated mortality of revision surgery, will become an increasingly important health issue, with a major impact upon health budgets. The overwhelming majority of hip and knee prostheses have metal or ceramic on polyethylene bearing surfaces. It is now apparent that most implants fail due to bone loss around them leading to loosening, and evidence is accumulating that polyethylene wear particles are a major contributing factor to this process. It is therefore vital that we obtain better understanding of the causes of implant failure in order to extend the life of these implants and this project is designed to do so.Read moreRead less
Urotensin-II In Human Heart: Investigation Of Mechanisms Involved In Cardiac Function
Funder
National Health and Medical Research Council
Funding Amount
$255,990.00
Summary
The normal function of the body is maintained by naturally occurring compounds. Some for example affect the heart, fine tuning it to make it beat faster or slower, or beat with greater or less force when required in different situations in health and disease. We were the first to show just recently that a small protein which occurs naturally in the body, called urotensin-II can affect the way the heart beats. We showed that extremely tiny amounts increase the force of the heart beat. Our finding ....The normal function of the body is maintained by naturally occurring compounds. Some for example affect the heart, fine tuning it to make it beat faster or slower, or beat with greater or less force when required in different situations in health and disease. We were the first to show just recently that a small protein which occurs naturally in the body, called urotensin-II can affect the way the heart beats. We showed that extremely tiny amounts increase the force of the heart beat. Our findings indicate that urotensin-II is the most potent heart stimulator identified to date. In patients with heart failure, short term stimulation of heart contraction is beneficial, supplying the heart and other organs with vital oxygen and nutrients. However, in the long term excessive stimulation causes worsening of the patients condition. Very little is currently known about the way in which urotensin-II alters heart function. The goal of our study is to understand the mechanism involved in urotensin-II mediated effects on the heart. This will involve identifying the location of urotensin-II and its receptors in the heart, and determining what signalling changes occur after the interaction of urotensin-II with its receptors. Urotensin-II must first be cleaved from a larger drug. We will determine where in the heart this cleavage occurs and whether the process is crucial to the ability of urotensin-II to stimulate contraction of the heart. Since stimulators of heart contraction are detrimental to patients with heart failure in the long term, we will determine whether these patients have more urotensin-II in their blood than patients who do not have heart failure. If the levels of urotensin-II are higher in heart failure patients, it may indicate a need to interfere with the interaction of urotensin-II with its receptors.Read moreRead less
Structural Studies On Cell Signalling Via The LIF Receptor And Gp130
Funder
National Health and Medical Research Council
Funding Amount
$453,943.00
Summary
The cytokines play important roles in the immune system during blood cell development and inflammation, and in nerve growth, bone remodeling, reproduction and heart development. Cell responses are initiated by a cytokine bringing together on the cell surface a receptor complex made up of multiple molecules. This project will investigate the atomic structure of the cell surface macromolecular complex, and hence the underlying mechanism by which cytokine signals are initiated.
Molecular Regulation Of Metabolism And Body Composition By Ski Via Crosstalk With Nuclear Hormone Receptor Signalling.
Funder
National Health and Medical Research Council
Funding Amount
$558,441.00
Summary
Obesity is a common and burdensome health problem in the community which leads to diabetes and heart disease. A number of factors, including hormones play important roles in determing risk of obesity. This study proposes to investigate whether the Ski gene which is a regulatory factor for many hormones affects metabolism in transgenic mouse models of altered Ski function. The proposed studies may identify Ski as a target for therapy for obesity and improvement in sketal muscle metabolism.