MOLECULAR STRUCTURE-FUNCTION RELATIONSHIPS OF THE NORADRENALINE TRANSPORTER & DRUG ACTION
Funder
National Health and Medical Research Council
Funding Amount
$188,912.00
Summary
The transmission of impulses by nerves is dependent on the release of chemicals, termed neurotransmitters, from the nerve. The neurotransmitter causes its effects and then its action is usually terminated by membrane proteins that transport the chemical back into the nerve. These proteins are termed 'transporters'. In the brain, psychostimulants such as cocaine and also drugs that are used in the therapy of conditions such as depression block the activity of the transporters for the neurotransmi ....The transmission of impulses by nerves is dependent on the release of chemicals, termed neurotransmitters, from the nerve. The neurotransmitter causes its effects and then its action is usually terminated by membrane proteins that transport the chemical back into the nerve. These proteins are termed 'transporters'. In the brain, psychostimulants such as cocaine and also drugs that are used in the therapy of conditions such as depression block the activity of the transporters for the neurotransmitters, noradrenaline, serotonin and dopamine. Recently, the structures of the transporter proteins have been determined using molecular biology techniques. The focus of this project is to determine the parts of the noradrenaline transporter protein structure that are important in determining its functions, utilising the knowledge that we now have about its molecular structure. This will lead to exciting advances in understanding the function of the noradrenaline transporter and these advances should ultimately lead to the development of more effective antidepressant drugs and of drugs to prevent the effects of psychostimulants such as cocaine.Read moreRead less
QacA-mediated Multidrug Resistance And Export In Staphylococcus Aureus
Funder
National Health and Medical Research Council
Funding Amount
$437,545.00
Summary
Strains of the pathogenic bacterium Staphylococcus aureus (Golden Staph) which are resistant to almost all available anti-staphylococcal agents are responsible for serious infections among hospitalised patients; in some hospitals such outbreaks reach epidemic proportions. In these bacteria, resistance has emerged to all classes of antimicrobial agents, including antibiotics and antiseptics-disinfectants commonly used in the hospital environment, largely due to the acquisition of resistance deter ....Strains of the pathogenic bacterium Staphylococcus aureus (Golden Staph) which are resistant to almost all available anti-staphylococcal agents are responsible for serious infections among hospitalised patients; in some hospitals such outbreaks reach epidemic proportions. In these bacteria, resistance has emerged to all classes of antimicrobial agents, including antibiotics and antiseptics-disinfectants commonly used in the hospital environment, largely due to the acquisition of resistance determinants. These determinants encode for proteins which provide the bacterial cell with a range of different biochemical mechanisms to evade antibiotic chemotherapy. Specifically, this project seeks to increase our understanding of proteins which confer resistance by pumping a variety of structurally-dissimilar antimicrobials out of the bacterial cell. Proteins which recognise such a broad spectrum of compounds are called multidrug resistance proteins and present a disturbing clinical threat since the acquisition of one such system by a cell may simultaneously decrease its susceptibility to a number of antimicrobials. Similar multidrug pumps are widespread in nature and are credited for resistance to antibiotics and other chemotherapeutic drugs in many pathogenic organisms, such as the bacteria responsible for tuberculosis, and in human cancer cells. In this project, we aim to characterise the QacA multidrug resistance protein which is involved in pumping many different antimicrobial compounds from staphylococcal cells. We will identify the regions of the QacA multidrug resistance protein which bind the compounds and examine how the protein expels them to give resistance. These studies are a prerequisite for the design of more effective antibacterial compounds able to bypass these drug resistance pumps, and will also provide fundamental knowledge applicable to the problem of multidrug resistance in other infectious diseases and cancer.Read moreRead less
The rhythm of the normal heart beat is controlled by electrical signals mediated by the flow of ions. The movement of ions across heart cell membranes is predominantly mediated by ion channel proteins. One of these proteins, called HERG, has some very unusual properties that make it well suited for suppressing abnormal heart beats. We propose to undertake a detailed investigation of the mechanisms by which HERG channels open and close. The results will provided a greater understanding of how HER ....The rhythm of the normal heart beat is controlled by electrical signals mediated by the flow of ions. The movement of ions across heart cell membranes is predominantly mediated by ion channel proteins. One of these proteins, called HERG, has some very unusual properties that make it well suited for suppressing abnormal heart beats. We propose to undertake a detailed investigation of the mechanisms by which HERG channels open and close. The results will provided a greater understanding of how HERG channels work and how altered function of HERG channels in patients with heart disease leads to an increased risk of abnormal heart rhythms and sudden cardiac death.Read moreRead less
Regulation Of PtdIns(3,4,5)P3 By Inositol Polyphosphate 5-phosphatases
Funder
National Health and Medical Research Council
Funding Amount
$200,880.00
Summary
Growing cells respond to growth factors by dividing and proliferating. Uncontrolled cell growth leads to cancer. Signals are released from the cell membrane following growth factor stimulation, that communicate via a complex network of intracellular signalling molecules, that instruct the nucleus to divide. One critical signalling network that mediates cell growth are the phosphoinositide messenger molecules. These signals are switched off by a family of proteins called inositol polyphosphate 5- ....Growing cells respond to growth factors by dividing and proliferating. Uncontrolled cell growth leads to cancer. Signals are released from the cell membrane following growth factor stimulation, that communicate via a complex network of intracellular signalling molecules, that instruct the nucleus to divide. One critical signalling network that mediates cell growth are the phosphoinositide messenger molecules. These signals are switched off by a family of proteins called inositol polyphosphate 5-phosphatases. We propose the 5-phosphatases are essential for normal cell growth. Several studies have suggested in their absence tumour formation may occurr. We have identified a new member of this enzyme family called SHIP-2. This proposal aims to investigate the mechanisms by which this enzyme family metabolises signalling molecules and thereby regulates cell growth. We will also characterize how the 5-phosphatases control the normal pathways by which primitive cells differeniate into mature cells.Read moreRead less
Glutamate is one of the major neurotransmitters in the brain. It plays a very important role in most brain functions such as the ability to learn and the development of memory, but the lack of control of glutamate concentrations in the brain also underlies many pathological changes that cause neurological disorders such Alzheimer's disease, disability following a stroke, motor neurone disease and Parkinson's disease. These diseases place an enormous social and economic burden on society and in o ....Glutamate is one of the major neurotransmitters in the brain. It plays a very important role in most brain functions such as the ability to learn and the development of memory, but the lack of control of glutamate concentrations in the brain also underlies many pathological changes that cause neurological disorders such Alzheimer's disease, disability following a stroke, motor neurone disease and Parkinson's disease. These diseases place an enormous social and economic burden on society and in order to better understand and treat these diseases it is important to understand some of the fundamental biochemical processes that underlie both normal and pathogical functions of the key neurotransmitter glutamate. This project will investigate how the concentrations of glutamate are tightly regulated to maintain normal brain function and also to avoid the potentially pathological consequences when these control mechanisms fail.Read moreRead less
The Structural Basis For The Control Of Cardiac And Skeletal Muscle By The Troponin Complex
Funder
National Health and Medical Research Council
Funding Amount
$369,003.00
Summary
Many key physiological processes are controlled by large, multi-protein complexes. These molecular machines ensure that signals transmitted in the body are correctly interpreted and amplified so as to control key body functions. The Troponin protein complex is one such large multi-protein complex which is the switch used to control both heart and skeletal muscle contraction in the body. The Troponin complex responds to increasing cellular calcium levels, switching the muscle on at high calcium. ....Many key physiological processes are controlled by large, multi-protein complexes. These molecular machines ensure that signals transmitted in the body are correctly interpreted and amplified so as to control key body functions. The Troponin protein complex is one such large multi-protein complex which is the switch used to control both heart and skeletal muscle contraction in the body. The Troponin complex responds to increasing cellular calcium levels, switching the muscle on at high calcium. When calcium returns to its normal basal level, the Troponin complex switches the muscle off. Naturally occurring genetic errors can lead to the malfunction of the Troponin complex. This, in turn, can lead to severe and possibly fatal diseases of the heart and muscle systems. To gain an understanding of these molecular diseases, it is important to understand the structure, dynamics and function of the Troponin complex. This project will use a newly-developed magnetic resonance method to monitor changes in the Troponin structure as a function of calcium level. Each component of the Troponin complex will be labeled with magnetic tags, allowing the determination of both structure and dynamics of Troponin, both in solution and in active muscle fibres. The study will result in a molecular understanding of how the Troponin switch works. This will give great insight in how mutations result in cardiac and muscular diseases.Read moreRead less