Defining A Role For The STONED Proteins In The Synaptic Vesicle Cycle
Funder
National Health and Medical Research Council
Funding Amount
$301,527.00
Summary
Nerve cells communicate with each other by means of chemical neurotransmitters. The level of communication is strictly controlled, and changes in the level, either up or down, is known as synaptic plasticity. This plasticity is thought to underly changes in the brain that account for both long and short term memory. Uncontrolled alterations in plasticity can also induce abnormal brain function, resulting in neurological disorders. Changes in the release of neurotransmitter are regulated at the m ....Nerve cells communicate with each other by means of chemical neurotransmitters. The level of communication is strictly controlled, and changes in the level, either up or down, is known as synaptic plasticity. This plasticity is thought to underly changes in the brain that account for both long and short term memory. Uncontrolled alterations in plasticity can also induce abnormal brain function, resulting in neurological disorders. Changes in the release of neurotransmitter are regulated at the molecular level by unknown mechanisms, however the chemical neurotransmitters are enclosed in small vesicles and it is believed that the control of the release of these vesicles, and their recycling, are important components of this mechanism. We have identified a gene that encodes two novel proteins of neurotransmission. Mutations that alter these genes can result in either increased or decreased synaptic activity. By using a combination of genetic and molecular techniques we propose to investigate how one of these two proteins operate to alter synaptic activity, as well as attempting to show how it interacts with other components of the synaptic machinery.Read moreRead less
Investigation Of The Molecular Mechanisms Underlying Alpha Synuclein Function At The Presynapse
Funder
National Health and Medical Research Council
Funding Amount
$419,180.00
Summary
Parkinson’s Disease (PD) is a common brain disease affecting 7 million people worldwide. It is caused by the death of brain cells. ?-synuclein is a protein in that brain that is likely to contribute to the cell death in PD, but the normal role of the protein remains unknown. This study will investigate the function of ?-synuclein in maintaining normal healthy brain activity. In addition, this work will help us understand how normal brain processes are affected in diseases such as PD.
Regulation Of Synaptic Vesicle Biogenesis For Synaptic Transmission
Funder
National Health and Medical Research Council
Funding Amount
$339,115.00
Summary
The overall aim is to better understand the molecular processes of nerve cell communication during learning, memory and abnormal brain activity that cause neurological diseases. The supply and generation (biogenesis) of synaptic vesicles (SVs) in nerve cells is critical to sustain neurotransmission. It requires complex protein interactions and signalling. Thus modulation of SV biogenesis at the molecular level will allows future development of new targeted treatments for neurological diseases.
The Functional Interplay Between Alpha Synuclein And Synaptophysin In Synaptic Vesicle Recycling
Funder
National Health and Medical Research Council
Funding Amount
$405,461.00
Summary
Parkinson’s Disease (PD) is the second most common neurodegenerative disorder, affecting 7 million people worldwide. ?-synuclein is a protein in that brain that is likely to contribute to the death of brain cells in PD, but the normal role of the protein remains unknown. This study will investigate the function of ?-synuclein in maintaining normal healthy brain activity. In addition, this work will help us understand the processes that go awry in neurodegenerative disease states such as PD.
Differential Regulation Of Two Modes Of Exocytosis By Protein Phosphatases
Funder
National Health and Medical Research Council
Funding Amount
$399,750.00
Summary
The release of signals from nerve endings (exocytosis) is of fundamental importance to nervous system function. The recent recognition that nerve cells can release transmitter by at least two distinct modes of exocytosis has led to the need for a deeper understanding of the mechanisms that regulate exocytosis. Our identification of the key role played by two enzymes, PP2A and PP2B, represents a major insight into the molecular mechansisms regulating this process. The experiments will lead to the ....The release of signals from nerve endings (exocytosis) is of fundamental importance to nervous system function. The recent recognition that nerve cells can release transmitter by at least two distinct modes of exocytosis has led to the need for a deeper understanding of the mechanisms that regulate exocytosis. Our identification of the key role played by two enzymes, PP2A and PP2B, represents a major insight into the molecular mechansisms regulating this process. The experiments will lead to the identification of how PP2A and PP2B are regulated at the molecular level and the targets that are important in the control of exocytosis. The project will also develop new tools to specifically manipulate the two modes of exocytosis in order to understand their contribution to normal and pathological neurotransmission. Strong stimulation of exocytosis is associated with learning and memory in normal brain and neuronal damage under certain pathological conditions. Since switching from 1 mode of exocytosis to another is also induced by strong stimulation, an understanding of the molecular mechanisms that control the different modes of exocytosis may eventually lead to clinical applications.Read moreRead less
Sulfonadyn-based Dynamin I-specific Inhibitors And Epilepsy
Funder
National Health and Medical Research Council
Funding Amount
$835,291.00
Summary
Epilepsy affects 1% of people, yet 30% do not respond to anti-epileptic drugs (AEDs). Traditional drug discovery fails to improve this situation. Our team discovered dynamin as a new target for better AED design and our lead sulphonadyns reduces seizures in animals. We will design better sulfonadyns that can ultimately be used for clinical trials by designing the drugs away from its actions outside of neurons. If successful, this will accelerate new AED development with less side-effects.
Recycling Of E-cadherin: Implications For Dynamic Cell Adhesion
Funder
National Health and Medical Research Council
Funding Amount
$250,494.00
Summary
E-cadherin is one of the major proteins responsible for mediating cell-to-cell adhesion in the body. During embryonic development E-cadherin is essential for establishing the normal body pattern and the cellular architecture of many epithelial organs. Throughout life E-cadherin serves to maintain epithelial barriers, such as the lining of the digestive tract. E-cadherin has been clearly identified as a tumour suppressor molecule: loss of normal E-cadherin function leads to tumour metastasis and ....E-cadherin is one of the major proteins responsible for mediating cell-to-cell adhesion in the body. During embryonic development E-cadherin is essential for establishing the normal body pattern and the cellular architecture of many epithelial organs. Throughout life E-cadherin serves to maintain epithelial barriers, such as the lining of the digestive tract. E-cadherin has been clearly identified as a tumour suppressor molecule: loss of normal E-cadherin function leads to tumour metastasis and cancer invasion. It is therefore essential to understand the physiological function and regulation of E-cadherin in cells. E-cadherin is normally expressed on the surface of cells for adhesion to neighbouring cells. Recently, we found that cells can internalise and recycle this surface E-cadherin: even in mature epithelia, a proportion of the E-cadherin molecules appear to undergo constant movement in and out of the cell. It is likely that this mechanism participates in the dynamic remodelling of adhesive contacts between cells in organs such as the gastrointestinal tract and during wound healing. Corruption of this recycling mechanism could also potentially contribute to tumorigenesis. In this grant we propose to build upon this discovery by investigating molecular and cellular mechanisms that mediate E-cadherin recycling. We will characterize the cellular pathways by which E-cadherin is trafficked. The signaling pathways that regulate recycling will be analysed, since these may be perturbed in cancer and inflammation. Other molecules that interact with E-cadherin will be studied to determine whether they too recycle. The information from these studies will have broad implications for understanding the role of E-cadherin in healthy organs and in common cancers.Read moreRead less
The Role Of Intersectin-1 In Endocytic Anomalies: Implications For Down Syndrome And Alzheimer's Disease
Funder
National Health and Medical Research Council
Funding Amount
$510,500.00
Summary
Individuals with Down syndrome have three copies of human chromosome 21, rather than the normal two. We have discovered a gene called Intersectin-1, located on human chromosome 21, that is expressed at higher levels than normal in individuals with Down syndrome. Intersectin-1 has a role in endocytosis, a process whereby cells take up molecules from the outside. Endocytosis occurs in all cells but is highly specialised in the brain where chemical transmitters are released and then rapidly recover ....Individuals with Down syndrome have three copies of human chromosome 21, rather than the normal two. We have discovered a gene called Intersectin-1, located on human chromosome 21, that is expressed at higher levels than normal in individuals with Down syndrome. Intersectin-1 has a role in endocytosis, a process whereby cells take up molecules from the outside. Endocytosis occurs in all cells but is highly specialised in the brain where chemical transmitters are released and then rapidly recovered by endocytosis in a process enabling neurones to pass signals to one another. A disturbance in endocytosis has been reported as the earliest hallmark of Alzheimer's disease in both non-Down syndrome and Down syndrome individuals. This disturbance is characterised by the presence of enlarged endosomes (small packages in neuronal cells containing chemical neurotransmitters formed during endocytosis). These enlarged endosomes are present long before the characteristic plaques of Alzheimer's disease appear. Since all individuals with Down syndrome develop Alzheimer's-like neuropathology, there must be a common disease mechanism that can be traced to the extra gene dosage from chromosome 21. We propose that a malfunctioning of Intersectin-1 is this common mechanism and we aim to test our hypothesis by the generation and analysis of mouse models of disrupted endocytosis.Read moreRead less