The body tightly controls when and where proteins are made. Likewise once a protein has performed its function, it must be removed. Targeted proteolysis serves to reset the cell so that it can respond anew to stimuli that trigger growth and cell development. The Siah proteins are a family of proteins that control the turnover of other proteins. Siah proteins are remarkably highly conserved in evolution, and counterparts of the human proteins can be found in fruitflies, worms and plants. There ar ....The body tightly controls when and where proteins are made. Likewise once a protein has performed its function, it must be removed. Targeted proteolysis serves to reset the cell so that it can respond anew to stimuli that trigger growth and cell development. The Siah proteins are a family of proteins that control the turnover of other proteins. Siah proteins are remarkably highly conserved in evolution, and counterparts of the human proteins can be found in fruitflies, worms and plants. There are three different types of Siah protein in mice and this study investigates the function of the each protein by creating mice that lack one or more of these proteins. Our work to date has revealed that the Siah genes are involved in growth and fertility of mammals. The genes are also important for cell division, which implicates them in proliferative diseases such as cancer.Read moreRead less
Receptor Signalling Through Intracellular Calcium Stores In Chromaffin Cells
Funder
National Health and Medical Research Council
Funding Amount
$461,000.00
Summary
The function of cells in the body is controlled by many hormones and neurotransmitters acting on the cell's surface. Hormones and transmitters mediate their effects by producing chemical signals within the cell that regulate its activities. One key cell signalling chemical is calcium, especially in nerve cells which have developed sophisticated mechanisms for using calcium to control their function. Recently, new levels of complexity have been discovered, both in how cell calcium levels are modi ....The function of cells in the body is controlled by many hormones and neurotransmitters acting on the cell's surface. Hormones and transmitters mediate their effects by producing chemical signals within the cell that regulate its activities. One key cell signalling chemical is calcium, especially in nerve cells which have developed sophisticated mechanisms for using calcium to control their function. Recently, new levels of complexity have been discovered, both in how cell calcium levels are modified by hormones and transmitters and in how these complex calcium signals are used by cells to control their function. This project will investigate how hormones and transmitters can produce different types of calcium signals in nerve cells, and how these signals affect different aspects of the nerve cell's function. In particular, it will establish how two different types of specialised calcium stores within nerve cells are used by different classes of hormone and transmitter, and the distinct cellular functions these two calcium stores can regulate. The results will provide fundamental new information on how nerve cells control their activity and may help identify potential new targets for drugs.Read moreRead less
Regulation Of PtdIns(3,4)P2 Signalling By Inositol Polyphosphate 4-phosphatase-1
Funder
National Health and Medical Research Council
Funding Amount
$557,939.00
Summary
Normally cells only divide when they receive a stimulus such as from a hormone or growth factor. One of the signaling pathways which responds to growth factor stimulation is the PI3-kinase pathway. This pathway has been implicated in many different human cancers which occur when cells divide uncontrollably and invade into the surrounding tissues. We have idenitified a novel enzyme called the inositol polyphosphate 4-phosphatase that appears to regulate cell proliferation and differentiation.
Signalling To Telomeres: Mechanisms Of Action Of TGFb
Funder
National Health and Medical Research Council
Funding Amount
$438,520.00
Summary
Cell lifespan is controlled by the enzyme called telomerase. High telomerase activity makes cell immortal as seen in cancer. We recently show that high telomerase activity can be inhibited by transforming growth factor b (TGFb). This may partly explain why TGFb inhibits cancer and induces cell ageing. This project furthers our investigation into the mechanism(s) by which TGFb inhibits telomerase. We recently noted for the first time that TGFb binds to telomerase gene directly, and this is contro ....Cell lifespan is controlled by the enzyme called telomerase. High telomerase activity makes cell immortal as seen in cancer. We recently show that high telomerase activity can be inhibited by transforming growth factor b (TGFb). This may partly explain why TGFb inhibits cancer and induces cell ageing. This project furthers our investigation into the mechanism(s) by which TGFb inhibits telomerase. We recently noted for the first time that TGFb binds to telomerase gene directly, and this is controlled by another protein called c-myc. This work will determine how telomerase is controlled by a balance between TGFb and c-myc in order to find ways to control telomerase and therefore cancer. We will use a combination of sophisticated techniques of cell molecular biology and biochemistry to pinpoint and target different molecules implicated in the actions of TGFb. This study will serve as an important baseline for more applied research in controlling ageing and cancer from development.Read moreRead less
C-Cbl-directed Leukaemogenesis: The Roles Of Core-Binding Factors And PI 3-kinase Signalling.
Funder
National Health and Medical Research Council
Funding Amount
$636,199.00
Summary
Myeloid leukaemia remains a major health problem with only about one third of patients being cured. More effective treatments are therefore needed. For these treatments to be developed more knowledge is required about the genetic and biochemical changes that cause myeloid leukaemia. This project aims to increase this knowledge by studying how cancer-causing proteins are involved in the development of myeloid leukaemia and how targeting these proteins can be used to develop new treatments.
Regulation Of TNF Receptor Expression By Omega-6 And Omega-3 Polyunsaturated Fatty Acids
Funder
National Health and Medical Research Council
Funding Amount
$226,320.00
Summary
This project looks at two major molecules which our body generates in trying to combat infections, a protein called tumor necrosis factor (TNF) and a fatty acid called arachidonic acid. In some cases the persistent production of elevated amounts of these molecules leads to highly crippling and debilitating diseases , such as rheumatoid arthritis, which pose a huge burden to our community. To develop medication to combat these diseases be it either vaccination or antiinflammatory drugs, there is ....This project looks at two major molecules which our body generates in trying to combat infections, a protein called tumor necrosis factor (TNF) and a fatty acid called arachidonic acid. In some cases the persistent production of elevated amounts of these molecules leads to highly crippling and debilitating diseases , such as rheumatoid arthritis, which pose a huge burden to our community. To develop medication to combat these diseases be it either vaccination or antiinflammatory drugs, there is a need to clearly define key components of the inflammatory response. Since TNF acts through a receptor we propose that a critical issue in the regulation of this inflammatory response is the changes in the expression of these receptors on cells of the immune system. Our preliminary work suggests that lipid molecules such as arachidonic acid (omega-6 fat) interacts with phagocytic cells and causes drammatic changes to the expression of this receptor. Our research proposal will look at this in more detail and place the observation into perspective in terms of parameters of the inflammatory reaction and associated diseases. Furthermore this concept will be examined in relation to the protective effects which the omega-3 fats found in fish oil have on these inflammatory diseases.Read moreRead less
The Role Of The Inositol Polyphosphate 4-phosphatase In Cellular Signalling
Funder
National Health and Medical Research Council
Funding Amount
$454,500.00
Summary
Cells respond to hormones, stress, growth factors and other environmental stimuli resulting in secretion, cell growth, cell division and other specialized functions. These cellular responses are dependent on the generation of intracellular signals that send messages either to the nucleus, the cytoskeleton or membrane compartments and thereby elicit a specific response. A specific subset of signalling molecules that are localized on membrane compartments are called phosphoinositides. We plan to i ....Cells respond to hormones, stress, growth factors and other environmental stimuli resulting in secretion, cell growth, cell division and other specialized functions. These cellular responses are dependent on the generation of intracellular signals that send messages either to the nucleus, the cytoskeleton or membrane compartments and thereby elicit a specific response. A specific subset of signalling molecules that are localized on membrane compartments are called phosphoinositides. We plan to investigate the role of a specific lipid called PtdIns(3,4)P2 that recruits signalling proteins to specific cellular membranes including the inner wall of the plasma membrane and vesicles found within the cell. We have identified and are currently characterizing a novel enzyme called the inositol polyphosphate 4-phosphatase that terminates the signals generated by PtdIns(3,4)P2. We are characterizing mice which lack this enzyme. 4-phosphatase deficient mice demonstrate significant abnormalities in the brain and bone marrow. These mice appear unable to make circulating platelets, small anucleate cells which are vital in preventing bleeding. We will determine how the 4-phosphatase functions in regulating platelet production, by examining the bone marrow and blood of these mice. These studies are significant as platelet production is essential for prevention of blood loss following trauma and also is of vital importance in conditions associated with blood clotting including heart attack and stroke. Secondly we have identified a related enzyme to the 4-phosphatase designated P-Rex-1 which is highly expressed in brain and nerve cells. This proposal aims to determine if P-Rex-1 promotes nerve development.Read moreRead less
Regulation Of The Sarcolemmal Na-K Pump By FXYD Proteins
Funder
National Health and Medical Research Council
Funding Amount
$268,264.00
Summary
Background. Pump molecules embedded in the membranes of all cells maintain a difference in composition between the cell content and the surrounding tissue fluids. Of these, the membrane sodium-potassium pump (Na+-K+ pump) is the most important. It uses metabolic energy generated in the cell to transport 3Na+ out in exchange for 2K+ transported in, and maintains a low concentration of Na+ and a high concentration of K+ within cells. The opposite applies to the surrounding tissue fluids. The conce ....Background. Pump molecules embedded in the membranes of all cells maintain a difference in composition between the cell content and the surrounding tissue fluids. Of these, the membrane sodium-potassium pump (Na+-K+ pump) is the most important. It uses metabolic energy generated in the cell to transport 3Na+ out in exchange for 2K+ transported in, and maintains a low concentration of Na+ and a high concentration of K+ within cells. The opposite applies to the surrounding tissue fluids. The concentration gradient for Na+ serves in mechanisms that couple transport of other ions and molecules to the downhill movement of Na+ in the direction determined by its concentration gradient. The transport of ions and molecules directly and indirectly due to the operation of the membrane Na+-K+ pump is very important for the function of all cells. Objectives. It is poorly understood how cells regulate the activity of their membrane Na+-K+ pumps. We will examine if small molecules (FXYD proteins) in the cell membrane, closely associated with the pump, regulate its activity. Methods. We will use a whole-cell patch clamping technique to attach small glass pipettes to single heart cells and replace their content with solutions in the pipettes. The technique allows real-time measurement of Na+-K+ pump activity because the 3:2 Na+:K+ exchange ratio generates an electrical current that can be measured in the single cells. The FXYD proteins will be produced in bacteria, purified and introduced into the heart cells by inclusion in the pipette solution that replace the cell content. Expected outcomes. Achieving this project's objectives will greatly enhance our understanding of Na+-K+ pump regulation. This is important because high levels of Na+ in heart cells is a pivotal abnormality in heart disease. Understanding the Na+-K+ pump can be activated to reduce cell Na+ levels should help design of treatments.Read moreRead less
Regulation Of PtdIns(3,4,5)P3 By Inositol Polyphosphate 5-phosphatases
Funder
National Health and Medical Research Council
Funding Amount
$200,880.00
Summary
Growing cells respond to growth factors by dividing and proliferating. Uncontrolled cell growth leads to cancer. Signals are released from the cell membrane following growth factor stimulation, that communicate via a complex network of intracellular signalling molecules, that instruct the nucleus to divide. One critical signalling network that mediates cell growth are the phosphoinositide messenger molecules. These signals are switched off by a family of proteins called inositol polyphosphate 5- ....Growing cells respond to growth factors by dividing and proliferating. Uncontrolled cell growth leads to cancer. Signals are released from the cell membrane following growth factor stimulation, that communicate via a complex network of intracellular signalling molecules, that instruct the nucleus to divide. One critical signalling network that mediates cell growth are the phosphoinositide messenger molecules. These signals are switched off by a family of proteins called inositol polyphosphate 5-phosphatases. We propose the 5-phosphatases are essential for normal cell growth. Several studies have suggested in their absence tumour formation may occurr. We have identified a new member of this enzyme family called SHIP-2. This proposal aims to investigate the mechanisms by which this enzyme family metabolises signalling molecules and thereby regulates cell growth. We will also characterize how the 5-phosphatases control the normal pathways by which primitive cells differeniate into mature cells.Read moreRead less
Post Synaptic Density Scaffold Proteins In The Growth Cone: Homer And Shank, Crucial For Calcium Signaling.
Funder
National Health and Medical Research Council
Funding Amount
$237,909.00
Summary
Our brain is a complex, yet precise electrical circuit. Understanding how the embryonic brain is wired has direct implications for all aspects of life, from the growing foetus in mother's womb, to learning algebra and for maintaining the active memories of our ageing population. This project aims to provide new insight into understanding how the embryonic brain is wired, crucial information for future pharmacological or gene therapy approaches to mental illness, ageing, and neuronal injury.