Characterization Of The 72 KDa Inositol Polyphosphate 5-phosphatase
Funder
National Health and Medical Research Council
Funding Amount
$454,050.00
Summary
Cells respond to external signals and the enviroment to undergo cell growth, secretion and or other specialized functions including control of cell death and or cell size. We have identified a new enzyme (72 kDa 5-phosphatase) which resides inside the cell, which we have evidence plays a role in regulating both the movement of intracellular vesicles and also lipid signals stimulated by insulin. We have characterised the phospholipids that the enzyme cleaves and demonstrated the generation of new ....Cells respond to external signals and the enviroment to undergo cell growth, secretion and or other specialized functions including control of cell death and or cell size. We have identified a new enzyme (72 kDa 5-phosphatase) which resides inside the cell, which we have evidence plays a role in regulating both the movement of intracellular vesicles and also lipid signals stimulated by insulin. We have characterised the phospholipids that the enzyme cleaves and demonstrated the generation of new cell signals at specific subcellular localizations on intracellular membranes. We predict the generation of these specific lipid signals may play a significant role in controlling the transport of intracellular cargo to specific sites in the cell. In this grant proposal we aim to examine the regulation of specialised cargo called the glucose transporter, which is found in fat and muscle cells, and also the mannose 6-phosphate receptor, which regulates the trafficking of specific enzymes which mediate digestion of proteins. These studies include the clarification of which phospholipid signals the enzyme terminates and where in the cell this occurs. Secondly, we will examine the movement of the glucose transporter GLUT-4 in unstimulated cells and in response to insulin and furthermore how expression of the novel enzyme regulates its movement. We will also examine the movement of the mannose 6-phosphate receptor and the specific phospholipid signals which control the route the receptor traffics, using inhibitors of lipid signals and expression of lipid phosphatases and kinases. We will also examine how our novel enzyme forms complexes with other molecules in the cell and characterise these novel molecules using basic biochemical assessment of enzyme activity and function. Finally we will examine the regulation of intracellular messages by our novel enzyme following insulin stimulation, which facilitates glucose uptake into the cell.Read moreRead less
Biochemical Analysis Of Akt 3-specific Signal Transduction
Funder
National Health and Medical Research Council
Funding Amount
$349,375.00
Summary
The Akt family of enzymes consists of 3 protein kinases (Akt 1,2 and 3) and has been shown to regulate many normal cellular processes such as cell proliferation, growth, survival and motility, as well as the growth of new blood vessels. All these processes are critical for cancers to grow. However, few studies have distinguished the roles of the individual family members. Our preliminary data revealed Akt3 is far more active than the other two forms. Furthermore, using our unique Akt3 specific a ....The Akt family of enzymes consists of 3 protein kinases (Akt 1,2 and 3) and has been shown to regulate many normal cellular processes such as cell proliferation, growth, survival and motility, as well as the growth of new blood vessels. All these processes are critical for cancers to grow. However, few studies have distinguished the roles of the individual family members. Our preliminary data revealed Akt3 is far more active than the other two forms. Furthermore, using our unique Akt3 specific antibody, we find Akt 3 protein and activity levels are high in rapidly proliferating ovarian cancer cell lines and in primary ovarian tumours. The aim of this proposal is to characterise the mode and role of signalling via Akt3, including the identification of targeted substrates and signaling pathways and the outcomes of Akt3 driven signaling on cellular properties. These studies will provide important clues to understanding how this family member functions in both health and disease. Elucidation of the basis of Akt3 dependent signalling will open the possibility for the development of drugs that interfere with Akt3 function (for example in high Akt 3 expressing tumours like those of the ovary). In the long term, extension of our profiling studies to other tumour types will give a novel insight into the extent of Akt3 de-regulation as a key mediator of cancer formation.Read moreRead less
Structural Investigation Into The Regulation Of The Colony Stimulating Factor Receptor, C-FMS.
Funder
National Health and Medical Research Council
Funding Amount
$287,321.00
Summary
The colony stimulating factor receptor, c-FMS is a member of a family of protein signalling molecules expressed on the cell surface that are implicated in the development of serious diseases in humans, such as inflammatory diseases and cancer. A number of important proteins bind to and regulate c-FMS in different ways. I intend to visualise these interactions to further understand how c-FMS activity is controlled by alternative means.
Developing orthogonal synthetic signaling cascades. This project proposes a generic approach for the construction of molecular switches based on artificially autoinhibited proteases. The bottom-up design of protein-based signaling networks is a key goal of synthetic biology. Yet, this remains elusive due to our inability to tailor-make signal transducers and receptors that can be readily compiled into defined signaling networks. Using structure-guided design and directed protein evolution, a set ....Developing orthogonal synthetic signaling cascades. This project proposes a generic approach for the construction of molecular switches based on artificially autoinhibited proteases. The bottom-up design of protein-based signaling networks is a key goal of synthetic biology. Yet, this remains elusive due to our inability to tailor-make signal transducers and receptors that can be readily compiled into defined signaling networks. Using structure-guided design and directed protein evolution, a set of protease-based signal transducers and ligand activated allosteric receptors will be created. The developed components are intended to be used to construct artificial signaling networks in mammalian cells that are orthogonal to the endogenous signaling cascades.Read moreRead less
New inhibitors of HIV based on cellular enzymes. Over 39 million people are infected with HIV worldwide. However, none of the most highly affected countries have yet reached the peak in AIDS-related illness and death, thus the global impact of HIV/AIDS will get significantly worse, before it gets better.
In Australia, HIV is again on the rise. Ironically, improved treatments that have extended life expectancy will cause the number of HIV infected Australians to rise for many years to come. ....New inhibitors of HIV based on cellular enzymes. Over 39 million people are infected with HIV worldwide. However, none of the most highly affected countries have yet reached the peak in AIDS-related illness and death, thus the global impact of HIV/AIDS will get significantly worse, before it gets better.
In Australia, HIV is again on the rise. Ironically, improved treatments that have extended life expectancy will cause the number of HIV infected Australians to rise for many years to come. Therefore many Australians will suffer from the combined impact of the AIDS illness itself, opportunistic infections, the side-effects of treatment and natural aging. We aim to develop new drugs to combat this disease to help people everywhere lead happier, healthier and more productive lives.Read moreRead less
Sensing atmosphere: Understanding the HNOX-protein gas-sensing capability and how it is affected by heme-oxidation. The project investigates how gas sensing heme-proteins from the novel HNOX (Heme-Nitric Oxide) family are able to discriminate between different gaseous ligands such as O2 and NO and how oxidation of the heme alters this response. The gas-sensing capability of the HNOX proteins is crucial for organisms ranging from bacteria to humans. Thus, understanding of these signalling mechani ....Sensing atmosphere: Understanding the HNOX-protein gas-sensing capability and how it is affected by heme-oxidation. The project investigates how gas sensing heme-proteins from the novel HNOX (Heme-Nitric Oxide) family are able to discriminate between different gaseous ligands such as O2 and NO and how oxidation of the heme alters this response. The gas-sensing capability of the HNOX proteins is crucial for organisms ranging from bacteria to humans. Thus, understanding of these signalling mechanisms will have a strong impact on many scientific fields from the control of pathogen growth to human blood pressure regulation. This collaboration will establish Australian scientists and as world-leading in the field of NO and redox signalling. This development will also be of substantial benefit for the training of the next generation of Australian students and scientists.Read moreRead less
Hierarchical Phosphorylation of Tyrosine Hydroxylase is Dependent on the Activation Sequence of Signaling Pathways. Protein phosphorylation is a fundamental process in biology. It controls protein expression and function in all cells. Hierarchical phosphorylation is defined as the phosphorylation of a protein at one site leading to an altered phosphorylation at another site on the same protein and an altered biological outcome. We have discovered that the enzyme tyrosine hydroxylase undergoes a ....Hierarchical Phosphorylation of Tyrosine Hydroxylase is Dependent on the Activation Sequence of Signaling Pathways. Protein phosphorylation is a fundamental process in biology. It controls protein expression and function in all cells. Hierarchical phosphorylation is defined as the phosphorylation of a protein at one site leading to an altered phosphorylation at another site on the same protein and an altered biological outcome. We have discovered that the enzyme tyrosine hydroxylase undergoes a form of hierarchical phosphorylation not previously reported. Here we examine hierarchical phosphorylation in rat and human tyrosine hydroxylase and its functional consequence in intact cells. The approaches and methods developed will also be applicable to investigation of hierarchical phosphorylation in other proteins.Read moreRead less
Molecular determinants of inflammatory caspase activity upon inflammasomes. Most processes fundamental to life rely on the timely, and regulated, execution of cellular functions. The innate immune system, in which both timing and regulation is paramount, rapidly detects invading microbes and induces a measured and timely antimicrobial response to clear infection. This project aims to address a key knowledge gap by characterising a mechanism for timely and controlled immune system activation and ....Molecular determinants of inflammatory caspase activity upon inflammasomes. Most processes fundamental to life rely on the timely, and regulated, execution of cellular functions. The innate immune system, in which both timing and regulation is paramount, rapidly detects invading microbes and induces a measured and timely antimicrobial response to clear infection. This project aims to address a key knowledge gap by characterising a mechanism for timely and controlled immune system activation and immune cell death via the non-canonical inflammasome. We do not currently understand how some immune pathways are turned on or off. This project will yield fundamental insight into mechanisms of mammalian inflammasome, inflammation and anti-microbial responses.Read moreRead less
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