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
Nuclear Functions Of Dengue NS5 Protein: Role In Disease
Funder
National Health and Medical Research Council
Funding Amount
$736,953.00
Summary
Our work indicates that the NS5 protein from Dengue virus (DV) has distinct sequences that enable it to traffic into and out of the host cell nucleus to exert pathogenic effects on transcription and thereby impair the host cell anti-viral and immune responses. We aim to characterise these properties in detail, and demonstrate their importance to DV pathogenicity using a novel animal model of the disease.
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
Novel Microtubule Association Sequences From Rabies Virus; Subversion Of Antiviral Responses And Use In Drug Delivery
Funder
National Health and Medical Research Council
Funding Amount
$529,632.00
Summary
The P-protein from rabies virus (RV) has distinct sequences that enable it to exploit the cellular skeleton (cytoskeleton) to localise efficiently in the host cell nucleus to exert pathogenic effects, or to perturb the cytoskeleton and thereby impair the host cell anti-viral response and immune response generally. We aim to characterise these properties in detail, demonstrate their importance to RV pathogenicity, and test the utility of the P-protein sequences in drug delivery.
Targeting TRPV4 Activation Mechanisms To Reveal Novel Pain Therapies
Funder
National Health and Medical Research Council
Funding Amount
$580,938.00
Summary
Pain nerves sense painful chemical and physical stimuli, by opening protein "ion channels" which let small electric currents traverse the cell membrane. This pain signal is transmitted to the spinal cord and then the brain, where it is perceived as pain and elicits a reaction. But we don't know how the ion channels open. This project will investigate how receptors for painful substances open ion channels to cause pain. Understanding this mechanism will help us to make new drugs to treat pain.
The Role Of Phosphorylation And Signalling For Invasion Of Plasmodium Falciparum Into Human Erythrocytes.
Funder
National Health and Medical Research Council
Funding Amount
$307,946.00
Summary
The intracellular signals that govern Plasmodium falciparum malaria invasion of the red blood cell are poorly understood. It is likely calcium dependent phosphorylation leads to recruitment and activation of a cascade of proteins. This study combines a break-through in purification of viable P. falciparum merozoites with proteomic analysis of phosphorylation states to assess intracellular signalling. It is expected the processes identified will be unique to P. falciparum and targetable by drugs.
Examining The Intracellular Pathways Regulated By GM-CSF In Macrophages And The Role In Diseases Such Arthritis.
Funder
National Health and Medical Research Council
Funding Amount
$63,567.00
Summary
A protein, termed GM-CSF, has been shown to be important in inflammatory conditions, like rheumatoid arthritis. GM-CSF can modify the properties of a key white blood cell, the macrophage, causing macrophages to produce factors harmful to host tissue. Various therapies are being developed to block GM-CSF, however discovering other drugs that block the intracellular actions of GM-CSF in macrophages are needed. Therefore the molecular pathways governing these actions need to be defined.