The Role Of Cholesterol In Patched/hedgehog Signalling During Mammalian Development.
Funder
National Health and Medical Research Council
Funding Amount
$198,660.00
Summary
Fluctuations in levels of cholesterol during development of the mammalian embryo have been shown to have catastrophic affects leading to gross deformities particularly in terms of brain and facial development. The requirement of the developing embryo for cholesterol has been linked to the patched-hedgehog signalling pathway which we have previously shown to be central to mammalian development as well as tumour formation. In particular, the patched protein which is responsible for regulating sign ....Fluctuations in levels of cholesterol during development of the mammalian embryo have been shown to have catastrophic affects leading to gross deformities particularly in terms of brain and facial development. The requirement of the developing embryo for cholesterol has been linked to the patched-hedgehog signalling pathway which we have previously shown to be central to mammalian development as well as tumour formation. In particular, the patched protein which is responsible for regulating signalling through this complex cascade of protein interactions has a domain similar to that which in other proteins has been shown to detect and respond to intracellular levels of cholesterol. The patched protein binds to hedgehog at the surface of the cell and mediates the transduction of the the hedgehog signal into the cell. By analogy to the role of sterol sensing domains in other proteins, we hypothesise that this domain in patched detects fluctuations in intracellular cholesterol levels which in turn alter trafficking of patched to the cell surface where it can participate in the hedgehog receptor complex. This hypothesis is supported by our preliminary data which suggests that patched is normally localised both at the cell surface and intracellularly. We are proposing a series of experiments to test our hypothesis, most of which deal with determing the localisation of patched in a cell culure system exposed to agents aimed at varying the intracellular levels of cholesterol. Subcellular localisation of patched will be analysed by immunofluorescence, electron microscopy and immunoblotting analysis. We will also test the ability of patched to aggregate at the cell surface with other molecules important in receiving and sending the hedgehog signal. The experiments in this proposal are likely to give the first clues as to the function of the sterol sensing domain in patched and its role in mediating the vital link between cholesterol and embryonic development.Read moreRead less
Co-ordinated Action of ATM and DNA-PK in DNA damage recognition. The aim of this project is to investigate the mechanism of repair of double straind breaks in DNA sustained after radiation damage. Specifically we will focus on two proteins ATM (mutated in the genetic disorder ataxia-telangiectasia) and DNA-PK mutated in scid mice. There two proteins recognize double straind breaks in DNA and signal this damage to the DNA repair machinery of the cell and to cell cycle checkpoints. The emphasis ....Co-ordinated Action of ATM and DNA-PK in DNA damage recognition. The aim of this project is to investigate the mechanism of repair of double straind breaks in DNA sustained after radiation damage. Specifically we will focus on two proteins ATM (mutated in the genetic disorder ataxia-telangiectasia) and DNA-PK mutated in scid mice. There two proteins recognize double straind breaks in DNA and signal this damage to the DNA repair machinery of the cell and to cell cycle checkpoints. The emphasis here will be in the relationship between the two proteins in co-ordinating the repair of breaks in DNA. This information will be important in understanding mechanisms for maintaining the integrity of the genome.Read moreRead less
To investigate the role of the protein kinase SMG-1 in the stress response. This project is included in the designated priority area of research Promoting and Maintaining Good Health and Ageing Well. It represents a mouse model to assist in the study of human disease. It is the first mouse model for SMG-1, a protein kinase that protects against a variety of different forms of stress. The strength of the model is that it can be combined with other mouse models to interrogate and elucidate the eve ....To investigate the role of the protein kinase SMG-1 in the stress response. This project is included in the designated priority area of research Promoting and Maintaining Good Health and Ageing Well. It represents a mouse model to assist in the study of human disease. It is the first mouse model for SMG-1, a protein kinase that protects against a variety of different forms of stress. The strength of the model is that it can be combined with other mouse models to interrogate and elucidate the events occurring in different pathways for stress. The expectation is that ground-breaking data will be generated with this model providing scientific leadership on the role of this protein. It will also assist in establishing new collaborations.Read moreRead less
Identification of functionally important autophosphorylation site(s) on ataxia telangiectasia and Rad 3 - related (ATR) protein kinase. The integrity of our genetic material must be maintained so that it can be passed on from one generation to the next and also to minimize the risk of cancer and other pathologies in an individual. There are multiple proteins involved in protecting our DNA including several enzymes that detect and signal DNA damage to a series of pathways involved in halting the ....Identification of functionally important autophosphorylation site(s) on ataxia telangiectasia and Rad 3 - related (ATR) protein kinase. The integrity of our genetic material must be maintained so that it can be passed on from one generation to the next and also to minimize the risk of cancer and other pathologies in an individual. There are multiple proteins involved in protecting our DNA including several enzymes that detect and signal DNA damage to a series of pathways involved in halting the passage of cells through the cell cycle so that repair can occur. This project studies the mechanism of action of one of these enzymes which will be of benefit in designing new compounds to fight disease. Read moreRead less
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Ribonucleic acid (RNA)-binding proteins regulate protein targeting and organelle biosynthesis. We will investigate a new paradigm in biology: the coordination of protein expression in space and time. Detailed knowledge will be gained about proteins that perform important roles in ensuring the proliferative potential of cells an essential aspect of stem cell biology, regenerative medicine and development of cancer. The study combines skills in several aspects of genetics, biochemistry and molecul ....Ribonucleic acid (RNA)-binding proteins regulate protein targeting and organelle biosynthesis. We will investigate a new paradigm in biology: the coordination of protein expression in space and time. Detailed knowledge will be gained about proteins that perform important roles in ensuring the proliferative potential of cells an essential aspect of stem cell biology, regenerative medicine and development of cancer. The study combines skills in several aspects of genetics, biochemistry and molecular cell biology and will therefore provide excellent training opportunities for PhD students and postdoctoral fellows in an internationally highly competitive field of research.Read moreRead less
Molecular mechanisms of stem cell self-renewal. Muscle growth and regeneration is critically dependent on its stem cell compartment. We have discovered that the p38 MAPK pathway is essential for stem cell self-renewal in the C2C12 myogenic cell line. This proposal seeks to understand the molecular basis of stem cell self-renewal in skeletal muscles, data that may be applicable to many stem cell systems, and to the enormous promise of stem cell therapies for injury and diseases of the aged. We wi ....Molecular mechanisms of stem cell self-renewal. Muscle growth and regeneration is critically dependent on its stem cell compartment. We have discovered that the p38 MAPK pathway is essential for stem cell self-renewal in the C2C12 myogenic cell line. This proposal seeks to understand the molecular basis of stem cell self-renewal in skeletal muscles, data that may be applicable to many stem cell systems, and to the enormous promise of stem cell therapies for injury and diseases of the aged. We will attempt to alter the balance of stem cell production by enforced p38 expression, and take microarray and proteomics approaches to define stem cell pathways.Read moreRead less