Structural Characterisation Of SNARE Protein Complexes Involved In Insulin-regulated Glucose Transport
Funder
National Health and Medical Research Council
Funding Amount
$320,803.00
Summary
Insulin-regulated glucose transportation is defective in type 2 diabetes, a disease that is a major health problem worldwide and in some cases can lead to death. The aim of this work is to investigate the molecular structure and function of proteins critical to the transportation and delivery of glucose to muscle and fat cells, which will lead to the validation of new therapeutic targets and the development of new treatments for diabetes.
Neuronal communication relies on the process of exocytosis by which neurons release a neurotransmitter. Exocytosis is critical for the simplest muscle movement to complex tasks such as learning and memory, and is altered in several neurodegenerative pathologies. We will investigate how the protein Munc18 controls exocytosis. This research will be important for understanding how neurons communicate in health and disease and will be relevant to other processes such as insulin release in diabetes.
Macrophages are important cells at the front-line of immunity where one of their main roles is to release anti-bacterial proteins. We will study the macrophage molecules, subcellular organelles and pathways that help to release these proteins to kill bacteria and fight infection. Our studies will identify new cellular targets for boosting immunity and treating inherited diseases with defective macrophage function.
Modulating Neuronal Secretion By The PI3-kinase Pathway
Funder
National Health and Medical Research Council
Funding Amount
$516,855.00
Summary
Neuronal communication relies on the process of exocytosis by which neurons release neurotransmitter. Exocytosis is critical for the simplest reflex movement to complex tasks such as learning and memory, and is altered in several neurodegenerative pathologies. We will investigate how certain lipids control exocytosis. This research is important for understanding how neurons communicate in health and disease and is relevant to other processes such as insulin release in diabetes.
Control Of SNARE-mediated Granule Fusion In Mast Cells
Funder
National Health and Medical Research Council
Funding Amount
$196,527.00
Summary
Asthma is an allergic disease affecting two million Australians. A major player in asthma is the mast cell which releases histamine when the cell is stimulated by antigen. The process by which histamine is released involves fusion of cytoplasmic granules containing the histamine with the cell surface membrane. The mechanism of this fusion process appears to be different in mast cells compared with other cells studied, raising the possibility that release of histamine, and hence the acute allergi ....Asthma is an allergic disease affecting two million Australians. A major player in asthma is the mast cell which releases histamine when the cell is stimulated by antigen. The process by which histamine is released involves fusion of cytoplasmic granules containing the histamine with the cell surface membrane. The mechanism of this fusion process appears to be different in mast cells compared with other cells studied, raising the possibility that release of histamine, and hence the acute allergic response, could be controlled if more were understood about the fusion process. This project aims to define the mechanism by which granules dock and then fuse with the cell surface. These are the two apects most likely to be unique in mast cells.Read moreRead less
Structural Studies On SNARE Proteins Involved In Insulin Action
Funder
National Health and Medical Research Council
Funding Amount
$308,263.00
Summary
Diabetes mellitus, a disease characterised by high blood glucose levels, is caused by a relative or absolute deficiency in the activity of insulin. The blood-glucose lowering action of insulin is a result of its ability to stimulate glucose uptake by fat and muscle cells. A major goal of Professor James' laboratory is to identify molecules that are involved in this insulin-regulated uptake of glucose. Professor James has identified and characterised the glucose transporter, GLUT4, a protein that ....Diabetes mellitus, a disease characterised by high blood glucose levels, is caused by a relative or absolute deficiency in the activity of insulin. The blood-glucose lowering action of insulin is a result of its ability to stimulate glucose uptake by fat and muscle cells. A major goal of Professor James' laboratory is to identify molecules that are involved in this insulin-regulated uptake of glucose. Professor James has identified and characterised the glucose transporter, GLUT4, a protein that is normally stored inside muscle and fat cells. In response to insulin stimulation, GLUT4 moves to the cell surface where it functions to transport glucose into the cell. Over the past 5 years Professor James laboratory has, in conjunction with other groups, discovered several key proteins that are involved in the insulin-regulated movement of GLUT4 within the cell. We plan to exploit the therapeutic potential of this biological system by obtaining high resolution three dimensional structures of these key proteins. The resulting structural information will allow us to develop compounds that modify the function of these key proteins. Such compounds could prove useful as novel therapeutic agents in the treatment of diabetes. The purpose of this proposal is to begin to implement this goal. By combining the knowledge and reagents coming out of the work on insulin-regulated glucose transport in Professor James' laboratory with the molecular and structural biology expertise in Dr Martin's, Dr Halliday's and Prof Craik's laboratories we are in a unique position to achieve this highly significant goal.Read moreRead less
Deciphering The Molecular Basis Of SM Regulation Of Exocytosis
Funder
National Health and Medical Research Council
Funding Amount
$515,564.00
Summary
Diabetes, obesity, heart disease and physical inactivity are major and escalating health problems within western societies. These problems are all linked to, or aggravate, the condition known as insulin resistance. Insulin resistance occurs when normal levels of insulin are insufficient to remove glucose from the blood. In the normal situation, insulin regulates glucose uptake into muscle and fat cells by stimulating the movement of a glucose transport protein from inside the cell to the cell su ....Diabetes, obesity, heart disease and physical inactivity are major and escalating health problems within western societies. These problems are all linked to, or aggravate, the condition known as insulin resistance. Insulin resistance occurs when normal levels of insulin are insufficient to remove glucose from the blood. In the normal situation, insulin regulates glucose uptake into muscle and fat cells by stimulating the movement of a glucose transport protein from inside the cell to the cell surface. The trafficking of this protein is somehow disrupted in insulin resistance. The purpose of this research is to follow up our exciting preliminary results on this system to shed light on the molecular processes that regulate the trafficking of the glucose transporter. Information resulting from our studies will lead to a better understanding of insulin-stimulated glucose transport and may also unravel the details of a related cellular secretion system that regulates neurotransmission. Our hope is that by understanding at the molecular level how cells regulate secretion, we can in the future develop therapeutics to counteract many of today s major health problems.Read moreRead less
Deciphering The Molecular Steps Leading To The Potentiation Of Neuronal Exocytosis By Arachidonic Acid
Funder
National Health and Medical Research Council
Funding Amount
$273,000.00
Summary
Release of hormones and neurotransmitters relies on a process called exocytosis which involves SNARE proteins: syntaxin1A and SNAP-25 on the target plasma membrane and VAMP on the vesicular membrane. Availability of the t-SNARE on the plasma membrane is believed to play a major role in controlling the amount of exocytosis. Syntaxin1A bound to Munc18 constitute an 'unproductive-reserve' pool of closed Syntaxin that cannot interact with SNAP-25. Intracellular messengers capable of releasing Syntax ....Release of hormones and neurotransmitters relies on a process called exocytosis which involves SNARE proteins: syntaxin1A and SNAP-25 on the target plasma membrane and VAMP on the vesicular membrane. Availability of the t-SNARE on the plasma membrane is believed to play a major role in controlling the amount of exocytosis. Syntaxin1A bound to Munc18 constitute an 'unproductive-reserve' pool of closed Syntaxin that cannot interact with SNAP-25. Intracellular messengers capable of releasing Syntaxin1A from Munc18 thereby making it available to interact with SNAP-25, are foreseen to play a major role in potentiating exocytosis - a process with ramification for memory and learning. We have identified arachidonic acid, a lipidic messenger which fullfil this role. For the first time we are in a position to manipulate at the molecular level different pools of SNARE proteins with direct implications for our understanding of the mechanism of secretion. Very few models are currently available to understand how learning and memory occur in the brain. Our research points to a new direction: the amount of 'active' and 'unproductive-reserve' pools of SNARE proteins present on the plasma membrane of neurosecretory cells are in dynamic equilibrium and arachidonic acid, a second messenger capable of trans-synaptic action, can modify this equilibrium resulting in an increase of the amount of 'active' SNARE thereby potentiating the amount of transmitter-hormone released by exocytosis. Importantly, this research lays the basis for a dynamic view of the secretory mechanism with important implications for treatment of diseases such as diabetes and neurodegenerative diseases. Our hope is that by understanding at the molecular level how secretory cells regulate the amount of their secretion, we will be in a position to modify these parameters in order to counteract illnesses of the nervous system.Read moreRead less