Analysis Of The Role Of Vesicle Docking/Fusion Proteins In Trafficking Of The Glut4 Glucose Transporter In Adipocytes
Funder
National Health and Medical Research Council
Funding Amount
$212,036.00
Summary
The objective of these studies is to understand the molecular mechanisms that are involved in the control of blood glucose levels by the hormone insulin. Elevated blood glucose levels following a meal stimulate the pancreas to release insulin into the circulation. Insulin acts to reduce blood sugar levels by stimulating the uptake of glucose into fat and muscle and suppressing glucose production by the liver. Defects in insulin action in these tissues are the primary cause of Type II diabetes. T ....The objective of these studies is to understand the molecular mechanisms that are involved in the control of blood glucose levels by the hormone insulin. Elevated blood glucose levels following a meal stimulate the pancreas to release insulin into the circulation. Insulin acts to reduce blood sugar levels by stimulating the uptake of glucose into fat and muscle and suppressing glucose production by the liver. Defects in insulin action in these tissues are the primary cause of Type II diabetes. The debilitating effects of Type II diabetes, the dramatic increase its incidence, and the expense of treating the symptoms of diabetic complications have lead to the realization that the disease represents a major health problem requiring substantial research and development efforts. The project will focus on insulin regulation of glucose uptake in fat cells. Insulin promotes glucose uptake into fat by activating an intracellular signaling pathway that triggers the translocation of a unique glucose transporter protein (Glut4) from storage sites inside the cell to the cell surface. Glut4 translocation is mediated by small membrane vesicles that function to sequester the glucose transporter inside cells in the absence of insulin, and to shuttle Glut4 to the cell surface in response to the hormone. Despite the central importance of this event to the maintenance of normal blood glucose levels, it is poorly understood. The studies will be directed towards investigating the cellular machinery involved in the latter stages of insulin-stimulated glucose uptake- the vesicle-mediated delivery of Glut4 to the cell surface. The objective of these studies is to better understand the molecular basis for Glut4 translocation, and regulation by the insulin signaling cascade. Accomplishment of this goal may suggest potential drug intervention strategies aimed at enhancing insulin-stimulated Glut4 translocation and promoting improved control of blood glucose levels in Type II diabetes.Read moreRead less
Insulin resistance (the inability of ordinarily insulin-sensitive tissues such as muscle and adipose tissue to respond to insulin) contributes to a number of diseases including diabetes and obesity. A key metabolic step in these tissues is the uptake of glucose from the blood stream. This step is accelerated by insulin thus allowing efficient clearance of glucose from the bloodstream after a meal. Our laboratory has played a major role in showing that insulin regulates glucose uptake into muscle ....Insulin resistance (the inability of ordinarily insulin-sensitive tissues such as muscle and adipose tissue to respond to insulin) contributes to a number of diseases including diabetes and obesity. A key metabolic step in these tissues is the uptake of glucose from the blood stream. This step is accelerated by insulin thus allowing efficient clearance of glucose from the bloodstream after a meal. Our laboratory has played a major role in showing that insulin regulates glucose uptake into muscle and adipose tissue by stimulating the movement of a glucose transport protein from inside the cell to the cell surface (see http:--www.imb.uq.edu.au-groups-james-glut4 for an animated description of this process). The purpose of this proposal is to dissect the molecular mechanisms by which this glucose transporter can be held inside the cell in the absence of insulin and then allowed to be released from this site moving to the surface in the presence of insulin. Our studies over the past 5 years have brought us much closer to understanding this process in detail. The identification of the molecules responsible for this regulatory step will not only aid our understanding of this process but it will also provide a valuable target for development of therapeutic agents that can be used to combat insulin resistance.Read moreRead less
Mechanism Of Action Of Sec1p-like Proteins In Membrane Trafficking.
Funder
National Health and Medical Research Council
Funding Amount
$440,250.00
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
Co-ordinated Action of ATM and DNA-PK in DNA damage recognition. The aim of this project is to investigate the mechanism of repair of double straind breaks in DNA sustained after radiation damage. Specifically we will focus on two proteins ATM (mutated in the genetic disorder ataxia-telangiectasia) and DNA-PK mutated in scid mice. There two proteins recognize double straind breaks in DNA and signal this damage to the DNA repair machinery of the cell and to cell cycle checkpoints. The emphasis ....Co-ordinated Action of ATM and DNA-PK in DNA damage recognition. The aim of this project is to investigate the mechanism of repair of double straind breaks in DNA sustained after radiation damage. Specifically we will focus on two proteins ATM (mutated in the genetic disorder ataxia-telangiectasia) and DNA-PK mutated in scid mice. There two proteins recognize double straind breaks in DNA and signal this damage to the DNA repair machinery of the cell and to cell cycle checkpoints. The emphasis here will be in the relationship between the two proteins in co-ordinating the repair of breaks in DNA. This information will be important in understanding mechanisms for maintaining the integrity of the genome.Read moreRead less
To investigate the role of the protein kinase SMG-1 in the stress response. This project is included in the designated priority area of research Promoting and Maintaining Good Health and Ageing Well. It represents a mouse model to assist in the study of human disease. It is the first mouse model for SMG-1, a protein kinase that protects against a variety of different forms of stress. The strength of the model is that it can be combined with other mouse models to interrogate and elucidate the eve ....To investigate the role of the protein kinase SMG-1 in the stress response. This project is included in the designated priority area of research Promoting and Maintaining Good Health and Ageing Well. It represents a mouse model to assist in the study of human disease. It is the first mouse model for SMG-1, a protein kinase that protects against a variety of different forms of stress. The strength of the model is that it can be combined with other mouse models to interrogate and elucidate the events occurring in different pathways for stress. The expectation is that ground-breaking data will be generated with this model providing scientific leadership on the role of this protein. It will also assist in establishing new collaborations.Read moreRead less
Identification of functionally important autophosphorylation site(s) on ataxia telangiectasia and Rad 3 - related (ATR) protein kinase. The integrity of our genetic material must be maintained so that it can be passed on from one generation to the next and also to minimize the risk of cancer and other pathologies in an individual. There are multiple proteins involved in protecting our DNA including several enzymes that detect and signal DNA damage to a series of pathways involved in halting the ....Identification of functionally important autophosphorylation site(s) on ataxia telangiectasia and Rad 3 - related (ATR) protein kinase. The integrity of our genetic material must be maintained so that it can be passed on from one generation to the next and also to minimize the risk of cancer and other pathologies in an individual. There are multiple proteins involved in protecting our DNA including several enzymes that detect and signal DNA damage to a series of pathways involved in halting the passage of cells through the cell cycle so that repair can occur. This project studies the mechanism of action of one of these enzymes which will be of benefit in designing new compounds to fight disease. Read moreRead less
A study of the nongenomic action of Vitamin D: proposed role of the nuclear VDR and downstream signalling molecules. Vitamin D (1,25D) activates genes in the nucleus through the vitamin D receptor (VDR). 1,25D can also elicit rapid responses at the plasma membrane. This action is critical to the activation of nuclear genes. We hypothesise that a proportion of the nuclear VDR is located at the plasma membrane where it stimulates downstream signalling molecules eg Ras, ERK1/2 and ERK5. We plan to ....A study of the nongenomic action of Vitamin D: proposed role of the nuclear VDR and downstream signalling molecules. Vitamin D (1,25D) activates genes in the nucleus through the vitamin D receptor (VDR). 1,25D can also elicit rapid responses at the plasma membrane. This action is critical to the activation of nuclear genes. We hypothesise that a proportion of the nuclear VDR is located at the plasma membrane where it stimulates downstream signalling molecules eg Ras, ERK1/2 and ERK5. We plan to explore this hypothesis and to identify the signalling molecules. We will also investigate our novel finding that a specific Ras isoform is involved in ERK5 activation. The work will provide new information on signalling pathways.Read moreRead less
Characterisation of the novel mitochondrial protein (CABC1/ADCK3) and its role in protecting against oxidative stress. This is the first detailed characterisation and mechanistic study on a protein that protects against oxidative stress and neurodegeneration. Demonstrating the basis for this oxidative stress and its possible contribution to the cellular phenotype will be of benefit in understanding the disease process and ultimately designing approaches to minimise oxidative stress. An investiga ....Characterisation of the novel mitochondrial protein (CABC1/ADCK3) and its role in protecting against oxidative stress. This is the first detailed characterisation and mechanistic study on a protein that protects against oxidative stress and neurodegeneration. Demonstrating the basis for this oxidative stress and its possible contribution to the cellular phenotype will be of benefit in understanding the disease process and ultimately designing approaches to minimise oxidative stress. An investigation of this protein presents an opportunity for the investigator to work at the forefront in this field adding to Australia's scientific leadership in the area. It also represents an ideal project for post-graduate training and is a collaboration between groups in Brisbane and Melbourne. Read moreRead less
A novel role for SMG-1 protein kinase in stress granule formation and the stress response. Humans are constantly exposed to agents in the environment that threaten the integrity of their cells and increases the risk of cancer and other pathologies. Cells have developed repair mechanisms to cope with damage to their DNA and avoid long term effects. The emphasis in this application is to investigate the mechanisms by which stress affects the transcriptional machinery in the cell. A description of ....A novel role for SMG-1 protein kinase in stress granule formation and the stress response. Humans are constantly exposed to agents in the environment that threaten the integrity of their cells and increases the risk of cancer and other pathologies. Cells have developed repair mechanisms to cope with damage to their DNA and avoid long term effects. The emphasis in this application is to investigate the mechanisms by which stress affects the transcriptional machinery in the cell. A description of the processes involved will assist in understanding how specific disease states arise and will provide a means of devising compounds/drugs to assist the response to stress. Read moreRead less