Defining The Insulin-signalling Defect In Human Insulin Resistance And Type 2 Diabetes
Funder
National Health and Medical Research Council
Funding Amount
$94,280.00
Summary
Problems with the way insulin removes glucose from the circulation contribute to developing type 2 diabetes. Despite research to date, controversy remains regarding the nature of known defects in insulin action and their relevance to humans. We plan to measure molecules involved in insulin action in muscle of people with insulin resistance, which is linked to diabetes. These studies will define new defects that cause insulin resistance and type 2 diabetes in humans.
Characterization Of The Phosphoinositide 5-phosphatase SKIP.
Funder
National Health and Medical Research Council
Funding Amount
$505,523.00
Summary
Growth factors and insulin stimulate a complex array of signals inside the cell, which are important for both cell survival and metabolism. A central intracellular signaling enzyme that initiates lipid messages that promote glucose uptake into the cell and promote cell survival is that generated by the PI3-kinase. This enzyme has increased activity in many cancers, and is also important in diabetes when the enzyme may be suppressed. Our grant proposes to investigate the function of another enzym ....Growth factors and insulin stimulate a complex array of signals inside the cell, which are important for both cell survival and metabolism. A central intracellular signaling enzyme that initiates lipid messages that promote glucose uptake into the cell and promote cell survival is that generated by the PI3-kinase. This enzyme has increased activity in many cancers, and is also important in diabetes when the enzyme may be suppressed. Our grant proposes to investigate the function of another enzyme called SKIP which acts within the cell to oppose the functions of the PI3-kinase. Several lines of evidence indicate SKIP may be important in both development and cancer. SKIP has been identified as a putative candidate gene for a developmental disorder known as Miller Dieker syndrome. This disease is associated with facial and significant brain abnormalities. In addition the SKIP gene is located on a chromosome that is frequently deleted in breast and colon cancer. SKIP is an enzyme that functions to remove phosphate molecules from PI3-kinase signaling molecules. SKIP has been shown to prevent glucose uptake into the cell by breaking down PI3-kinase signals. We have recently demonstrated SKIP phosphatase activity can be inhibited by binding to another protein called suppressor of death domains (SODD). We plan to investigate the effects this complex has on SKIP enzyme activity, and how this complex plays a role in regulating PI3-kinase signals that promote glucose uptake. Secondly, we plan to investigate the function of SKIP in an intact animal by making mice which lack SKIP(knock out mice). Given SKIP is implicated in a developmental syndrome and insulin signaling, we can delineate the functional significance of SKIP and the molecular pathways regulated by this enzyme.Read moreRead less
Molecular Characterization Of E-cadherin-activated Rac Signaling
Funder
National Health and Medical Research Council
Funding Amount
$220,500.00
Summary
Interactions between cells and their neighbouring cells control many important processes in the body. The adhesion molecule, E-cadherin, is a major protein that controls interactions between cells in epithelial tissues (e.g. breast, lung, gut). E-cadherin is essential for these tissues to form normally, and loss of E-cadherin function contributes to the progression of many human cancers (especially common cancers such as breast and lung). Understanding how E-cadherin controls normal epithelial c ....Interactions between cells and their neighbouring cells control many important processes in the body. The adhesion molecule, E-cadherin, is a major protein that controls interactions between cells in epithelial tissues (e.g. breast, lung, gut). E-cadherin is essential for these tissues to form normally, and loss of E-cadherin function contributes to the progression of many human cancers (especially common cancers such as breast and lung). Understanding how E-cadherin controls normal epithelial cell function will therefore provide key insights into the bases for tumor progression. In this study we will examine how E-cadherin signals to the interior of cells. We have recently discovered a new signaling pathway that is turned on when E-cadherin is activated. Understanding the fundamental elements of this signaling pathway will provide invaluable insights into how cells recognize one another during health and disease.Read moreRead less
Type 2 diabetes represents an escalating global health problem. In Australia 7.2% of the population has diabetes but an additional 16% have difficulty handling glucose, a problem which frequently precedes the development of diabetes. Resistance of tissues to the action of insulin is an essential pre-requisite for type 2 diabetes but is also closely associated with the syndrome of obesity, dyslipidaemia, hypertension and cardiovascular diseases (Syndrome X). Genetic factors combined with a high c ....Type 2 diabetes represents an escalating global health problem. In Australia 7.2% of the population has diabetes but an additional 16% have difficulty handling glucose, a problem which frequently precedes the development of diabetes. Resistance of tissues to the action of insulin is an essential pre-requisite for type 2 diabetes but is also closely associated with the syndrome of obesity, dyslipidaemia, hypertension and cardiovascular diseases (Syndrome X). Genetic factors combined with a high caloric intake and a sedentary lifestyle are together responsible for the development of insulin resistance. From evidence that we and others have obtained in recent years it is evident that an important mediator of insulin resistance is the amount of fat which accumulates in muscle and liver. One way in which this abnormality seems to cause insulin resistance is through interference with the normal signalling mechanism which causes increased glucose metabolism in response to insulin. While experiments in cell systems have identified some candidate molecules that may be involved, a need exists to demonstrate whether their dysregulation actually causes the insulin resistance in the whole animal or human, or are merely associated with it. We will use novel techniques to manipulate the levels of one of these candidate genes, protein kinase B-Akt, and its regulators in the muscle of rodents. We will then examine the effects of these manipulations on insulin resistance using a combination of metabolic and molecular tests. Building upon earlier work we will also determine how important different subtypes of this molecule are for both normal and abnormal insulin-glucose metabolism, and whether these molecules or others in the pathway are more important in insulin resistance. This knowledge will be invaluable in tailoring specific novel treatment strategies or drugs for prevention or treatment of insulin resistance, and thus reducing the burden of type 2 diabetes and Syndrome X.Read moreRead less
Role Of The Inositol Polyphosphate 4-phosphatase Type 2 In Human Breast Cancer
Funder
National Health and Medical Research Council
Funding Amount
$611,032.00
Summary
Breast cancer is the most invasive cancer in females, affecting 1 in 9 women before the age of 85. Normally cells only divide when they receive a stimulus from a hormone or growth factor. The PI3K pathway responds to these stimuli and has been implicated in cancer when cells divide uncontrollably and invade surrounding tissue. We have identified a potential cancer suppressing gene, 4-ptase-2 that turns off the PI3K growth signals. We aim to characterize the role of 4-ptase-2 in breast cancer.
In the asthmatic lung structural changes, such as increased deposition of proteins which form the scaffolding of the airways (the extracellular matrix proteins), and an increased mass of bronchial smooth muscle cells occur. Many of these critical structural changes are not reversed or prevented with current asthma therapy, thus we need to investigate, by using lung cells and tissues , why they happen and how we can prevent them.
Understanding SOCS3 Inhibition Of JAK Activity In Myeloproliferative Disorders
Funder
National Health and Medical Research Council
Funding Amount
$524,820.00
Summary
The myeloproliferative disorders are diseases in which abnormal blood cell development leads to a risk of stroke, thrombosis, hemorrhage and leukemia. Remarkably, three of these disorders are caused by an error in a single enzyme that makes it over active. The enzyme, JAK2, controls how cells respond to hormone-like messengers called cytokines. We are investigating a cellular pathway that inhibits this enzyme in order to understand the progression and potential treatment of the disorders.
Akt Kinase Signalling, Regulated Vesicular Transport And Lipid Metabolism
Funder
National Health and Medical Research Council
Funding Amount
$337,850.00
Summary
How do metabolic cues tell cancer cells to make more membranes, or fat cells to make more fat? These are some of the questions that underpin this project, which explores the link between cell signalling, protein trafficking and fat metabolism. Specifically, we aim to define the role of an important signalling molecule (Akt) in intracellular transport and activation of a key integrator of fat metabolism (SREBP). This work will have wide-ranging implications for human health and disease.