The role of the protease inhibitor Serpinb9 in antigen cross-presentation by dendritic cells. This project will provide fundamental new insights into antigen cross-presentation, a crucial facet of the immune system's response to viral infection or neoplastic cells. It will also provide a basis for future studies into mechanisms of immune tolerance and enhance our understanding of autoimmune disease.
Molecular mechanisms of catalysis and the basis of substrate specificity in polysaccharide hydrolases. Reaction intermediates along hydrolytic pathways and molecular determinants of substrate specificity of barley B-glucan exo- and endohydrolases will be defined using crystallographic and kinetic analyses. These enzymes are of central importance in cell wall metabolism during development of higher plants, and in plant-pathogen interactions. Realization of the project objectives will not only pro ....Molecular mechanisms of catalysis and the basis of substrate specificity in polysaccharide hydrolases. Reaction intermediates along hydrolytic pathways and molecular determinants of substrate specificity of barley B-glucan exo- and endohydrolases will be defined using crystallographic and kinetic analyses. These enzymes are of central importance in cell wall metabolism during development of higher plants, and in plant-pathogen interactions. Realization of the project objectives will not only provide fundamental information on catalytic mechanisms, but will also provide opportunities to manipulate enzyme specificity. Further, site-directed mutagenesis of the enzymes will be used to generate glycosynthases, which will be evaluated for their ability to synthesise novel oligosaccharide and polysaccharide products, some of which might show immunomodulating activity.Read moreRead less
Structures and Functions of Bacterial Replisomal Proteins. DNA replication in all organisms requires many proteins to interact in a structure called the replisome. The bacterial replisome is assembled about the DnaB helicase, a motor protein that moves along DNA, separating the strands of duplex regions in its path. This project aims to develop understanding of the chemistry of DnaB and other replisomal proteins: their structures, how they work, and how they interact to assemble the replisome. T ....Structures and Functions of Bacterial Replisomal Proteins. DNA replication in all organisms requires many proteins to interact in a structure called the replisome. The bacterial replisome is assembled about the DnaB helicase, a motor protein that moves along DNA, separating the strands of duplex regions in its path. This project aims to develop understanding of the chemistry of DnaB and other replisomal proteins: their structures, how they work, and how they interact to assemble the replisome. This has the potential to lead to design of new antibacterial drugs.
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The regulation of signalling molecules in Saccharomyces Cerevisiae by inositol polyphosphate 5-phosphatases. Phosphoinositide signalling molecules regulate the actin cytoskeleton, secretion, vesicular trafficking and cell growth and death. We have identified, cloned and characterised a family of signal terminating enzymes called inositol polyphosphate 5-phosphatases (5-phosphatases) that regulate phosphoinositide signalling molecules. We have cloned and characterised four distinct 5-phosphatases ....The regulation of signalling molecules in Saccharomyces Cerevisiae by inositol polyphosphate 5-phosphatases. Phosphoinositide signalling molecules regulate the actin cytoskeleton, secretion, vesicular trafficking and cell growth and death. We have identified, cloned and characterised a family of signal terminating enzymes called inositol polyphosphate 5-phosphatases (5-phosphatases) that regulate phosphoinositide signalling molecules. We have cloned and characterised four distinct 5-phosphatases in the yeast Saccharomyces Cerevisiae and demonstrated by both deletion and overexpression studies that these enzymes regulate the actin cytoskeleton, endocytosis and secretion. This research proposal aims to investigate the signalling complexes the 5-phosphatases form with specific actin binding and or regulatory proteins, investigate the complex interactions of phosphoinositide lipid phosphatases and the roles they play in regulating secretion from the endoplasmic reticulum and finally characterize a novel 5-phosphatase that we have recently identified. Collectively the outcome of these studies will provide novel information about the functionallly significant signalling pathways regulated by this important enzyme family.Read moreRead less
The role of PtdIns(4,5)P2 in cellular responses in Saccharomyces cerevisiae. This grant application falls under the criteria of frontier technologies in genomics/phenomics and complex systems. We are characterizing a highly conserved network of signaling molecules regulated by complex large families of enzymes that regulate the bending of membranes, and cellular events including cell division in plants, yeast and mammalian cells. We have developed cutting edge novel technologies to localize sign ....The role of PtdIns(4,5)P2 in cellular responses in Saccharomyces cerevisiae. This grant application falls under the criteria of frontier technologies in genomics/phenomics and complex systems. We are characterizing a highly conserved network of signaling molecules regulated by complex large families of enzymes that regulate the bending of membranes, and cellular events including cell division in plants, yeast and mammalian cells. We have developed cutting edge novel technologies to localize signaling on specific intracellular membranes and visualise the role cellular lipids play in forming tubules in cells. This project will result in the presentation of Australian research at international forums and support the training of PhD students.Read moreRead less
A novel link between metabolism and host defence. This project aims to delineate how a protein modification that consists of the addition of a small sugar to cellular proteins, known as O-GlcNAcylation, provides a link between metabolism and complex cell functions. The model for these studies is a cell type of the immune system known as dendritic cells. Upon encountering pathogens these cells undergo metabolic changes that increase the rate of O-GlcNAcylation of proteins involved in immune respo ....A novel link between metabolism and host defence. This project aims to delineate how a protein modification that consists of the addition of a small sugar to cellular proteins, known as O-GlcNAcylation, provides a link between metabolism and complex cell functions. The model for these studies is a cell type of the immune system known as dendritic cells. Upon encountering pathogens these cells undergo metabolic changes that increase the rate of O-GlcNAcylation of proteins involved in immune responses, altering their function. This project will study how O-GlcNAcylation works and is regulated. The project expects to develop new technology and provide high-level training, increasing the competitiveness of the strategic biotechnology sector in AustraliaRead moreRead less
Structural basis of the neuroendocrine enzyme GAD65-mediated autoimmunity in Type 1 Diabetes. More than 80 per cent of patients with Type 1 Diabetes develop antibodies against the neuroendocrine enzyme GAD65. This project will use state-of-the art techniques to study the interaction of GAD65 with antibodies in molecular detail. This will provide key insights into the molecular mechanisms of autoimmune disease.
Angiogenic defects in mutant growth plate cartilage reveal new modulators of vascular invasion. Converting cartilage to bone requires blood vessel invasion from the bony interface. This project will test, in vitro and in vivo, the hypothesis that collagen fragments regulate blood vessel invasion into cartilage. This data will have implications for processes requiring new blood vessels such as bone growth, cancer, inflammation and ischemia.
Monolayer crystallization of membrane proteins. Membrane proteins comprise 25-40% of all proteins and conduct a myriad of finely tuned reactions in every cell. Despite their importance and diversity only ~40 membrane protein structures have been solved, due to the difficulty of producing high quality 2D and 3D crystals. We propose to develop and use the new monolayer crystallization technique, which employs a lipid monolayer as a crystallization template for 2D crystal production. A number of ....Monolayer crystallization of membrane proteins. Membrane proteins comprise 25-40% of all proteins and conduct a myriad of finely tuned reactions in every cell. Despite their importance and diversity only ~40 membrane protein structures have been solved, due to the difficulty of producing high quality 2D and 3D crystals. We propose to develop and use the new monolayer crystallization technique, which employs a lipid monolayer as a crystallization template for 2D crystal production. A number of important membrane proteins are available for these structural studies including ABC transporters, Caveolin-3 and the NS1 protein of Dengue virus, all of which are difficult to crystallize using conventional techniques.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