Effects Of Mutations In The Conserved Cysteine Loop Of The GABA-A Receptor
Funder
National Health and Medical Research Council
Funding Amount
$417,750.00
Summary
Inhibiting excitatory signals in the brain is the function of large proteins called GABA-A receptors. Many general anaesthetics, tranquillisers and anti-epileptic drugs act by modulating GABA-A receptors. Modern surgery would not be possible without rendering patients unconscious with general anaesthetics. However, these valuable drugs can still have unwanted side effects: for example, some of them can affect cardiac and respiratory function. There is still a need for new, more effective general ....Inhibiting excitatory signals in the brain is the function of large proteins called GABA-A receptors. Many general anaesthetics, tranquillisers and anti-epileptic drugs act by modulating GABA-A receptors. Modern surgery would not be possible without rendering patients unconscious with general anaesthetics. However, these valuable drugs can still have unwanted side effects: for example, some of them can affect cardiac and respiratory function. There is still a need for new, more effective general anaesthetics. One in every 200 people in Europe and North America suffers from epilepsy and 3% of the population suffers from anxiety. Leading, currently used general anaesthetics, anxiolytic and anti-epileptic drugs act on GABA-A receptors in the brain. The potential annual market for these drugs has been estimated to be US $2.7 billion. The world market for anaesthetics in 1999 was US $1.6 billion. All were discovered serendipitously. If the molecular site and mode of action of these drugs were understood, it is possible that new, more selective drugs could be discovered. The information gained in this project about GABA-A receptors is expected to be useful in understanding how these receptors work and in developing a new generation of drugs acting on GABA-A receptors. Specific mutations in GABA-A receptors can have a profound influence on their function. Studying the effects of mutations is slowly giving us more information about the ion channel region and drug binding sites. Recently, mutations in GABA-A receptors have been found to be associated with some forms of epilepsy. In this project, we plan to examine the effects of mutations in highly conserved residues of a small region of subunits of the GABAA receptor because: (1) we (and others) have preliminary evidence that this loop forms a connection between the GABA binding site and the ion channel and (2) we think that this part of the receptor is vital for the effects of some drugs.Read moreRead less
Subunit stoichiometry and arrangement in the glycine receptor. Glycine receptors are important for nervous system function. These receptors comprise a mixture of 5 alpha and beta subunits arranged around a central ion-conducting pore. The subunit stoichiometry (i.e., numbers of alpha and beta subunits) and arrangement (i.e., subunit order) are unknown. The first aim of this project is to define these parameters using tethered subunits. The second aim is to use the tethered subunits to probe th ....Subunit stoichiometry and arrangement in the glycine receptor. Glycine receptors are important for nervous system function. These receptors comprise a mixture of 5 alpha and beta subunits arranged around a central ion-conducting pore. The subunit stoichiometry (i.e., numbers of alpha and beta subunits) and arrangement (i.e., subunit order) are unknown. The first aim of this project is to define these parameters using tethered subunits. The second aim is to use the tethered subunits to probe the structure and function of glycine and zinc binding sites at an unprecedented level of resolution. The results will provide crucial new information concerning glycine receptor structure and function.Read moreRead less
Gating and permeation in ClC channels. Chloride ion channels are essential proteins in all living cells but, compared to other channels, little is known of their structure or how this defines and controls chloride transport. We will produce both normal and structurally modified (mutant and known to cause disease) chloride channels in cultured cells by genetic engineering so that we can analyse channel function using a combination of electrophysiological and chemical methods. We expect to learn ....Gating and permeation in ClC channels. Chloride ion channels are essential proteins in all living cells but, compared to other channels, little is known of their structure or how this defines and controls chloride transport. We will produce both normal and structurally modified (mutant and known to cause disease) chloride channels in cultured cells by genetic engineering so that we can analyse channel function using a combination of electrophysiological and chemical methods. We expect to learn which channel parts are fundamental and how subtle changes in structure can alter the opening and closing of these channels and the way that chloride passes through them.Read moreRead less
Expression and characterisation of nutrient transporters from the intracellular malaria parasite, Plasmodium falciparum. The malaria parasite invades the red blood cells of its host and this provides it with a safe haven in which to grow and replicate. Within the red blood cell, the parasite takes up nutrients and excretes metabolic wastes via specialised membrane transport proteins which are, as yet, very poorly understood. The sequencing of the malaria parasite genome has enabled us to ident ....Expression and characterisation of nutrient transporters from the intracellular malaria parasite, Plasmodium falciparum. The malaria parasite invades the red blood cells of its host and this provides it with a safe haven in which to grow and replicate. Within the red blood cell, the parasite takes up nutrients and excretes metabolic wastes via specialised membrane transport proteins which are, as yet, very poorly understood. The sequencing of the malaria parasite genome has enabled us to identify candidates for a wide variety of these proteins. The aim of this project is to establish systems in which the functional properties of these transporter proteins may be characterised in detail.Read moreRead less
Special Research Initiatives - Grant ID: SR0354715
Funder
Australian Research Council
Funding Amount
$40,000.00
Summary
The Australian Plant Nutriomics Network. The Australian Plant Nutriomics Network will link Australian scientists investigating aspects of the plant nutriome - the summation of processes that deliver nutrients and water from soil to plants. The network will establish a coordinated approach to understanding genes, proteins and metabolites involved in element acquisition and how their functions are linked to soil conditions to maximise food quality and overcome soil environmental challenges. Inter ....The Australian Plant Nutriomics Network. The Australian Plant Nutriomics Network will link Australian scientists investigating aspects of the plant nutriome - the summation of processes that deliver nutrients and water from soil to plants. The network will establish a coordinated approach to understanding genes, proteins and metabolites involved in element acquisition and how their functions are linked to soil conditions to maximise food quality and overcome soil environmental challenges. International articulation will ensure information exchange and enhance postgraduate and postdoctoral training by reciprocal visits and focused workshops. A major goal will be a strategy to integrate research using a complex systems approach to problems.Read moreRead less
Conantokin selectivity for heteromeric N-methyl-D-aspartate (NMDA) receptors. NMDA receptors are ligand gated ion channels formed by heterogeneous population of subunits with distinct pharmacological and biophysical properties. The heterogeneic receptors are differentially expressed during development and play an important role in many physiological and pathological processes. Conantokins are toxins isolated from Conus venoms, which target NMDA receptor subunits with high affinity. The primary g ....Conantokin selectivity for heteromeric N-methyl-D-aspartate (NMDA) receptors. NMDA receptors are ligand gated ion channels formed by heterogeneous population of subunits with distinct pharmacological and biophysical properties. The heterogeneic receptors are differentially expressed during development and play an important role in many physiological and pathological processes. Conantokins are toxins isolated from Conus venoms, which target NMDA receptor subunits with high affinity. The primary goal of this study is to examine the effects of conantokins on the molecular properties of different NMDA receptor subtypes in vivo and in vitro.Read moreRead less
How does clusterin protect cells from stresses? We recently discovered that clusterin: (i) is the only known secreted (ie extracellular) mammalian chaperone and (ii) can protect proteins and cells from stresses.These breakthrough advances provide the first unifying biological function for this protein - in whole organisms, clusterine is likely to protect tissues and organs form biologyical stresses. The work proposed will provide quantum advances in our understanding of the molecular basis by wh ....How does clusterin protect cells from stresses? We recently discovered that clusterin: (i) is the only known secreted (ie extracellular) mammalian chaperone and (ii) can protect proteins and cells from stresses.These breakthrough advances provide the first unifying biological function for this protein - in whole organisms, clusterine is likely to protect tissues and organs form biologyical stresses. The work proposed will provide quantum advances in our understanding of the molecular basis by which clusterin effects its protective actions. We expect to demonstrate that clusterin protects cells form stresses by exerting its chaperone action at or near the cell surface and to identify specific regions and structural features of the clusterine molecule important in its chaperone action.Read moreRead less