Probing JNK MAPK function with peptide inhibitors. It has generally been accepted that the JNK MAPK family of protein kinases is rapidly and potently activated following the exposure of mammalian cells to stresses and cytokines. However, their biological role has remained controversial. We believe that this problem reflects the lack of a generally applicable and specific JNK MAPK inhibitor. In this project we continue our characterisation of a small peptide inhibitor developed in our laboratori ....Probing JNK MAPK function with peptide inhibitors. It has generally been accepted that the JNK MAPK family of protein kinases is rapidly and potently activated following the exposure of mammalian cells to stresses and cytokines. However, their biological role has remained controversial. We believe that this problem reflects the lack of a generally applicable and specific JNK MAPK inhibitor. In this project we continue our characterisation of a small peptide inhibitor developed in our laboratories. We aim to determine its mechanism of inhibition, the specificity of interaction, and to evolve more effective inhibitors. With these new inhibitors, we can effectively address the biological roles of these kinases.Read moreRead less
Isolation and analysis of novel caspases. Apoptosis is an evolutionarily conserved cellular process which must be tightly controlled for normal development and to avoid disease. Rapid progress has been made recently in the elucidation of apoptotic pathways, but many important components are likely still unknown. The caspases constitute the effector arm of apoptotic signalling pathways and some members play important roles in cytokine maturation. We aim to identify novel caspases using an innovat ....Isolation and analysis of novel caspases. Apoptosis is an evolutionarily conserved cellular process which must be tightly controlled for normal development and to avoid disease. Rapid progress has been made recently in the elucidation of apoptotic pathways, but many important components are likely still unknown. The caspases constitute the effector arm of apoptotic signalling pathways and some members play important roles in cytokine maturation. We aim to identify novel caspases using an innovative technique, and to characterise their function and regulation. Molecules identified in this project may be candidate targets for therapies which modulate apoptosis for treatment or prevention of disease, or diagnostic reagent development.Read moreRead less
Regulation Of SRC-Family And Focal Adhesion Kinase Function
Funder
National Health and Medical Research Council
Funding Amount
$381,338.00
Summary
Cells in our bodies stick to one another and to the cementing material called extracellular matrix surrounding them. An ezyme called focal adhesion kinase (FAK) is a major regulator of cell stickiness. It can catalyze the covalent attachment of a chemical group called phosphate to specific cellular protein. This proposal aims at studying how FAK is regulated by insulin stimulation and how FAK is regulated by a tumour suppressor called PTEN. Results of the study will shed light on how abberration ....Cells in our bodies stick to one another and to the cementing material called extracellular matrix surrounding them. An ezyme called focal adhesion kinase (FAK) is a major regulator of cell stickiness. It can catalyze the covalent attachment of a chemical group called phosphate to specific cellular protein. This proposal aims at studying how FAK is regulated by insulin stimulation and how FAK is regulated by a tumour suppressor called PTEN. Results of the study will shed light on how abberrations in the regulation and PTEN contribute to the development of development defects, heart attack, and the spreading of cancer cells.Read moreRead less
Regulation Of The Tumour Suppressor PTEN By Phosphorylation And Oligomerization
Funder
National Health and Medical Research Council
Funding Amount
$241,650.00
Summary
The tumour suppressor PTEN is an enzyme involved in controlling cell growth, cell death, and cell migration. PTEN was identified as a tumour suppressor because many tumour cells were found to carry mutations in the PTEN gene that cause the loss of PTEN protein or the loss of PTEN enzyme activity. Hereditary mutations of the PTEN gene are the causes of a rare genetic disease called Cowden's disease. Cowden's disease patients are predisposed to developing skin, thyroid, and breast cancers. In labo ....The tumour suppressor PTEN is an enzyme involved in controlling cell growth, cell death, and cell migration. PTEN was identified as a tumour suppressor because many tumour cells were found to carry mutations in the PTEN gene that cause the loss of PTEN protein or the loss of PTEN enzyme activity. Hereditary mutations of the PTEN gene are the causes of a rare genetic disease called Cowden's disease. Cowden's disease patients are predisposed to developing skin, thyroid, and breast cancers. In laboratory conditions, increasing the abundance of PTEN in tumour cells such as brain and prostate tumour cells can suppress their growth, hence its role as a tumour suppressor. In addition to its role as a tumour suppressor, PTEN controls cancer cell spreading. Although much is known about the involvement of PTEN in cancer formation and the spreading of cancer cells, how PTEN suppresses tumour cell growth and spreading is not fully understood. The enzyme activity of PTEN enhances the removal of a chemical group called phosphate group from proteins and the fat-soluble compounds called phospholipids in the cell membrane. The ability of PTEN to suppress cell growth and spreading is due to its enzyme activity. However, exactly how the enzyme activity of PTEN is regulated is not well understood. In order for PTEN to efficiently enhance the removal of phosphate group from specific cellular proteins and phospholipids, PTEN needs to be located in close vicinity to these proteins and phospholipids. However, exactly how PTEN moves to the locations where these proteins and phospholipids are present remains elusive. This proposal aims at studying the regulation of PTEN enzyme activity and movement inside the cells. Results of the proposed studies will shed new light on how PTEN gene mutations contribute to cancer formation and the spreading of cancer cells and may facilitate the search for the cure of cancers.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
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
Post-translational Control Of Indoleamine 2,3-dioxygenase
Funder
National Health and Medical Research Council
Funding Amount
$511,294.00
Summary
It is apparent that a protein called indoleamine 2,3-dioxygenase is important for controlling the immune system of relevance to various normal and disease conditions including pregnancy, cancer, inflammation, infectious disease and autoimmunity. Despite this little is known about how this important protein is controlled. The aim of this project is to better understand how this protein is regulated that can highlight ways in which to alter the enzymes activity to modulate immune responces.
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
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