The Activation Of Lipoprotein Lipase By Apolipoprotein C-II
Funder
National Health and Medical Research Council
Funding Amount
$250,500.00
Summary
Abnormalities in blood lipid levels are common in our society. Treatment of these conditions adds a heavy burden to national health-care costs. Lipoprotein lipase is a plasma enzyme that plays a central role in maintaining safe blood lipid levels. The action of lipoprotein lipase in subjects on a western diet leads to the hydrolysis of about 150g of plasma triacylglycerol daily. Naturally occurring mutations in lipoprotein lipase, associated with a complete loss of enzyme activity, result in a h ....Abnormalities in blood lipid levels are common in our society. Treatment of these conditions adds a heavy burden to national health-care costs. Lipoprotein lipase is a plasma enzyme that plays a central role in maintaining safe blood lipid levels. The action of lipoprotein lipase in subjects on a western diet leads to the hydrolysis of about 150g of plasma triacylglycerol daily. Naturally occurring mutations in lipoprotein lipase, associated with a complete loss of enzyme activity, result in a high blood-lipids that can lead to premature atherosclerosis. Regulation of lipoprotein lipase occurs via an interaction with the regulatory protein apolipoprotein C-II. Individuals with apolipoprotein C-II deficiency also exhibit abnormal plasma lipid levels with an associated increased risk of coronary heart disease. These considerations demonstrate that the activation of lipoprotein lipase by apolipoprotein C-II is pivotal to the maintenance of normal blood lipid levels. The present proposal will establish the structure and orientation of apolipoprotein C-II in a lipid environment and provide a structural model for the activation of lipoprotein lipase by apolipoprotein C-II. These molecular details will serve as a model for the regulatory interactions of other apolipoproteins within lipoprotein particles and will generate leads for the development of new strategies for the treatment of blood lipid irregularities.Read moreRead less
Characterization Of 72 And 52 KDa Inositol Polyphosphate 5-phosphatases: Role In Vesicular Trafficking And Cell Death
Funder
National Health and Medical Research Council
Funding Amount
$408,055.00
Summary
Cells respond to the external environment, stress, hormones and grow th factors by generating messages inside the cell that send a signal to the nucleus that stimulates cell growth. One such signalling network is that produced by membrane lipids known as phosphoinositides. Enzymes or kinases that modify these membrane lipids in particular an enzyme known as the PI 3-kinase generate potent signalling molecules that regulate cell growth. It has been shown by many studies that signals generated by ....Cells respond to the external environment, stress, hormones and grow th factors by generating messages inside the cell that send a signal to the nucleus that stimulates cell growth. One such signalling network is that produced by membrane lipids known as phosphoinositides. Enzymes or kinases that modify these membrane lipids in particular an enzyme known as the PI 3-kinase generate potent signalling molecules that regulate cell growth. It has been shown by many studies that signals generated by the PI 3-kinase are amplified in certain human cancers. Inherited cancer syndromes have been described in which the cell has lost the ability to switch off these lipid messenger molecules. The current project aims to investigate two recently identified enzymes called 5-phosphases that have the ability to terminate PI 3-kinase membrane signals. Both these enzymes were isolated and characterized by the host laboratory and it is predicted they will play distinct roles in the cell. The 72 kDa 5-phosphatase is predicted to regulate protein and vesicular trafficking to the surface of cell. This proposal aims to investigate if the 72 kDa 5-phosphatase can regulate the intracellular sorting of new proteins within the cell. We have also noted the 72 kDa 5-phosphatase may play a role in the development of the nervous system in particular the ability of nerves to send branches out and differentiate. This proposal will investigate this hypothesis. The second enzyme that we have isolated is a 52 kDa 5-phosphatase. This enzyme is present in many cells. We have compelling evidence that the enzyme forms a complex with a recently decribed protein called SODD that stops cells from dying in response to inappropropirate signals. We predict the 52 kDa 5-phosphatase may function to prevent prolonged cell survival as is observed in cancer. We will investigate if this enzyme regulates the cell death pathway and if increased or decreased levels of the 52 kDa 5-phosphatase alter cell survivalRead moreRead less
Using the fractionation of hydrogen and carbon isotopes to analyse the mechanisms of the primary processes of photosynthesis. The primary processes of CO2 fixation and reduction in photosynthesis leave their signatures in the isotopic composition of organic matter. Although these signatures are used widely in geochemistry, biology and climatology to infer the dynamics and history of the biosphere, the information they provide about the mechanisms of the processes that produce them has not been e ....Using the fractionation of hydrogen and carbon isotopes to analyse the mechanisms of the primary processes of photosynthesis. The primary processes of CO2 fixation and reduction in photosynthesis leave their signatures in the isotopic composition of organic matter. Although these signatures are used widely in geochemistry, biology and climatology to infer the dynamics and history of the biosphere, the information they provide about the mechanisms of the processes that produce them has not been exploited fully. We propose to map the underlying biochemistry responsible for fractionation of hydrogen isotopes, to assess its ability to indicate the water relations of plants, and to use carbon-isotope discrimination to probe the catalytic chemistry of the CO2-fixing enzyme, Rubisco.Read moreRead less
Enantioselective nitrilases from filamentous fungi. The optical characteristics (chirality) of chemical precursors are important for many fine chemicals. Chiral intermediates are in high demand by the pharmaceutical and agrochemical industries for the preparation of bulk drug intermediates and agricultural products. Nitriles are attractive starting points but their conversion to corresponding amides and carboxylic acids generates significant wastes. Their hydrolysis can be performed under mil ....Enantioselective nitrilases from filamentous fungi. The optical characteristics (chirality) of chemical precursors are important for many fine chemicals. Chiral intermediates are in high demand by the pharmaceutical and agrochemical industries for the preparation of bulk drug intermediates and agricultural products. Nitriles are attractive starting points but their conversion to corresponding amides and carboxylic acids generates significant wastes. Their hydrolysis can be performed under mild conditions by enzymes termed nitrilases. We will work on fungal nitrilases as they present a globally attractive, yet untapped commercial target. The outcome for Applimex will be a suite of biocatalysts specific for the production of key intermediates for drug and agrochemical syntheses.Read moreRead less
Mammalian histidine kinase: its characterisation and role in hepatic cellular proliferation. Protein kinases regulate all aspects of cellular metabolism, but there is a class of protein kinase, histidine kinases, which exists in mammalian cells, about which remarkably little is understood. This project will be the first detailed characterisation of such an enzyme and investigation of its cellular function. The enzyme to be characterised is hepatic and it has been implicated in the regulation of ....Mammalian histidine kinase: its characterisation and role in hepatic cellular proliferation. Protein kinases regulate all aspects of cellular metabolism, but there is a class of protein kinase, histidine kinases, which exists in mammalian cells, about which remarkably little is understood. This project will be the first detailed characterisation of such an enzyme and investigation of its cellular function. The enzyme to be characterised is hepatic and it has been implicated in the regulation of DNA replication in regenerating liver. We shall obtain a detailed picture of the role of this histidine kinase in liver cell biology and an insight into the more general biological role of this class of enzyme.Read moreRead less
A global approach to structure, assembly and function of yeast mitochondrial ATP synthase. ATP synthase is responsible for the synthesis of the ubiquitous energy substance ATP in living cells. This multisubunit enzyme complex is a molecular rotatory motor whose mechanism relies on functional dynamic interactions of the component protein subunits of the complex. Using a combination of powerful and sophisticated molecular biology techniques the functional and dynamic contacts made by subunits wi ....A global approach to structure, assembly and function of yeast mitochondrial ATP synthase. ATP synthase is responsible for the synthesis of the ubiquitous energy substance ATP in living cells. This multisubunit enzyme complex is a molecular rotatory motor whose mechanism relies on functional dynamic interactions of the component protein subunits of the complex. Using a combination of powerful and sophisticated molecular biology techniques the functional and dynamic contacts made by subunits within the complex, or between ATP synthase and other enzyme complex involved in energy production (including other ATP synthase complexes) will be investigated. New and significant insights into one of the most fundamental and challenging enzymes of life will be obtained.Read moreRead less
The Structure Function and Biology of Serpins. The serpin family of proteins control protease activity, in a variety of biological systems, via a dramatic conformational change. We are 4 leaders in the serpin reseacrh field using an integrated approach of biochemistry, biophysics, molecular biology, cell biology, structural biology and bioinformatics to analyse every facet of serpin structure, function and biology. We will apply and develop novel technologies that will determine how these confor ....The Structure Function and Biology of Serpins. The serpin family of proteins control protease activity, in a variety of biological systems, via a dramatic conformational change. We are 4 leaders in the serpin reseacrh field using an integrated approach of biochemistry, biophysics, molecular biology, cell biology, structural biology and bioinformatics to analyse every facet of serpin structure, function and biology. We will apply and develop novel technologies that will determine how these conformational changes are achieved and how they are controlled. Our increased understanding of this inhibitor - enzyme interaction will have implications to other proteins which undergo conformational change and biotechnology.Read moreRead less
Structural and functional studies on prokaryote serpins. Proteins are the machines of life, many of which undergo complex movements to achieve function. The basic research described in this proposal will result in major outcomes in understanding how proteins fold, undergo complex changes in conformation, and misfold to dysfunctional states. As a result, the study will contribute fundamental knowledge that will underpin research in the fields of structural biology, protein design and protein fo ....Structural and functional studies on prokaryote serpins. Proteins are the machines of life, many of which undergo complex movements to achieve function. The basic research described in this proposal will result in major outcomes in understanding how proteins fold, undergo complex changes in conformation, and misfold to dysfunctional states. As a result, the study will contribute fundamental knowledge that will underpin research in the fields of structural biology, protein design and protein folding. Through providing insight into protein misfolding, the work will will contribute to our understanding of degenerative misfolding pathologies that affect the ageing population and thus targets the 'ageing well ageing productively' priority goal.Read moreRead less
Characterisation of a powerful molecular motor, the FtsK DNA translocase. The FtsK protein is a fast and powerful molecular motor, a pump that can, and does, move an entire bacterial chromosome. This project will uncover the detail of the mechanism used by this motor to convert the cell's chemical energy source Adenosine Triphosphate (ATP) into movement of DNA; revealing the molecular detail of a fast and powerful motor.
Modulation of cellular metabolism by protein and peptide peroxides. Oxidation of peptides and proteins by a wide range of reactive radicals and other oxidants, in the presence of oxygen, generates protein peroxides. These species are now recognised to be key intermediates in both the deterioration of foods (e.g. development of rancidity and off-flavours, changes in colour and texture) and a number of human diseases, including cancer, heart disease and ageing. How these peroxides cause biological ....Modulation of cellular metabolism by protein and peptide peroxides. Oxidation of peptides and proteins by a wide range of reactive radicals and other oxidants, in the presence of oxygen, generates protein peroxides. These species are now recognised to be key intermediates in both the deterioration of foods (e.g. development of rancidity and off-flavours, changes in colour and texture) and a number of human diseases, including cancer, heart disease and ageing. How these peroxides cause biological perturbations is poorly understood. The proposed studies will provide valuable information as to how these peroxides affect cellular metabolism and provide key leads as to strategies which may prevent such damage.Read moreRead less