Molecular Characterisation Of Receptor Activity Modifying Proteins (RAMPs)
Funder
National Health and Medical Research Council
Funding Amount
$340,399.00
Summary
The maintenance of optimum health and function of living cells, and consequently that of the whole organism, depends on how cells respond to a multitude of physical and chemical stimuli that continually bombard them. The majority of the chemical stimuli such as hormones and neurotransmitters impart their actions not by directly entering the cell, but instead, by binding to a specific receiver protein at the cell surface called a receptor. In one class of such receptors called G protein-coupled r ....The maintenance of optimum health and function of living cells, and consequently that of the whole organism, depends on how cells respond to a multitude of physical and chemical stimuli that continually bombard them. The majority of the chemical stimuli such as hormones and neurotransmitters impart their actions not by directly entering the cell, but instead, by binding to a specific receiver protein at the cell surface called a receptor. In one class of such receptors called G protein-coupled receptors, the transmission of the message to the interior of the cell involves yet another protein called G protein. These receptors are the most abundant type of cell surface receptors and form the targets for nearly 50% of currently used therapeutic drugs. It is, therefore, extremely important to unravel how each of these components works. To make this process even more complex, it was recently shown that another newly discovered group of proteins called receptor activity modifying proteins (RAMPs) too play a critical role in some systems. We have shown that RAMPs interact with many G protein-coupled receptors and that they have a wider range of actions than has previously been appreciated. Moreover, it has been shown that the RAMP-receptor interface is a viable target for drug development. Understanding the extent to which RAMPs interact with G protein-coupled receptors, how they interact with the receptors and the consequences of this interaction forms the basis of the current proposal. Such knowledge is central to the unraveling of the processes involved in the maintenance of health, abnormalities that lead to disease, and in the development of new treatments.Read moreRead less
Understanding Selective Drug Signaling At G Protein-coupled Receptors
Funder
National Health and Medical Research Council
Funding Amount
$362,206.00
Summary
The maintenance of optimum health and function living cells, and consequently that of the whole organism, depends on how cells respond to a multitude of physical and chemical stimuli that continually bombard them. The majority of the chemical stimuli such as hormones and neurotransmitters impart their actions not by directly entering the cell, but instead, by binding to a specific reciever protein at the cell surface called receptor. In one class of such receptors called G protein-coupled recept ....The maintenance of optimum health and function living cells, and consequently that of the whole organism, depends on how cells respond to a multitude of physical and chemical stimuli that continually bombard them. The majority of the chemical stimuli such as hormones and neurotransmitters impart their actions not by directly entering the cell, but instead, by binding to a specific reciever protein at the cell surface called receptor. In one class of such receptors called G protein-coupled receptors, the transmission of the message to the interior of the cell involves yet another protein called G protein. These receptors are the most abundant type of cell surface receptors and form the targets for nearly 50% of currently used therapeutic drugs. It is, therefore, extremely important to unravel how each of these components works, and in particular to know how they work in living cells. This project utilizes state-of-the-art methodologies to examine interactions between receptors and their cognate G proteins, in living cells and in real-time. The work will answer fundamental questions about the nature of G protein-coupled receptor signaling, in particular whether new classes of drugs can be identified that more selectively activate signaling pathways or factors that attenuate signaling. This work has potential for future development of more effective therapeutic agents.Read moreRead less
FOXO Proteins And Protection From Cardiac Ischaemic Injury
Funder
National Health and Medical Research Council
Funding Amount
$354,375.00
Summary
Reduced blood supply to the heart can initiate a heart attack that results in damage to the heart muscle. Loss of muscle tissue under these conditions initiates pathological growth of the heart and can eventually lead to the development of heart failure, a major cause of death and disability in western countries. Treatment with growth factors can prevent the acute damage and loss of cells, but these cause detrimental effects on other tissues. For these reasons, it is necessary to establish ways ....Reduced blood supply to the heart can initiate a heart attack that results in damage to the heart muscle. Loss of muscle tissue under these conditions initiates pathological growth of the heart and can eventually lead to the development of heart failure, a major cause of death and disability in western countries. Treatment with growth factors can prevent the acute damage and loss of cells, but these cause detrimental effects on other tissues. For these reasons, it is necessary to establish ways to activate protective pathways in the heart without causing unwanted effects on other tissues. To this end, we have identified for the first time in the heart members of a newly described family of gene regulators that can cause cell death by increasing expression of cytotoxic factors. We showed that these FKHRor FOXO family members are regulated in the heart and that they are active in generating cytotoxic factors. We now plan to establish whether FOXO proteins are involved in causing cell death during heart attack and whether manipulating their activities can be cardioprotective.Read moreRead less
Evaluation Of Orally Active Anti-inflammatory C5a Receptor Antagonists In A Transgenic Rat Motor Neurone Disease Model
Funder
National Health and Medical Research Council
Funding Amount
$533,578.00
Summary
Motor neurone disease is a rapidly progressive and incurable disease, usually ending in death within 3-5 years of diagnosis. The disease usually arrives without warning, and results in a progressive loss of muscle control. There is no effective treatment, and available drugs increase life span by a few weeks at best. There is evidence that the disease involves an inflammatory component, but available anti-inflammatory drugs are ineffective. We have developed a new class of anti-inflammatory drug ....Motor neurone disease is a rapidly progressive and incurable disease, usually ending in death within 3-5 years of diagnosis. The disease usually arrives without warning, and results in a progressive loss of muscle control. There is no effective treatment, and available drugs increase life span by a few weeks at best. There is evidence that the disease involves an inflammatory component, but available anti-inflammatory drugs are ineffective. We have developed a new class of anti-inflammatory drugs, known as C5a antagonists, and in preliminary experiments have shown they are therapeutically effective in a transgenic rat model of motor neurone disease. We propose to investigate in more detail how these drugs work in the rat model, and demonstrate that a specific inflammatory pathway, which we can now block, is responsible for some of the disease's progression. This work may lead to an entirely new class of drugs being used to treat patients with this drastic disease.Read moreRead less
Molecular Regulation Of The Type 1 Angiotensin Receptor
Funder
National Health and Medical Research Council
Funding Amount
$695,440.00
Summary
Angiotensin II is a hormone made in our bodies in response to a decrease in blood pressure (or salt in our bloodstream). It causes our blood vessels to constrict, makes us thirsty, and induces salt and fluid retention via an effect on the kidneys, thereby increasing blood pressure. In some cardiovascular diseases, the generation of angiotensin II or our sensitivity to this hormone is elevated. It is therefore crucial that we understand how angiotensin II works and how its actions in the body are ....Angiotensin II is a hormone made in our bodies in response to a decrease in blood pressure (or salt in our bloodstream). It causes our blood vessels to constrict, makes us thirsty, and induces salt and fluid retention via an effect on the kidneys, thereby increasing blood pressure. In some cardiovascular diseases, the generation of angiotensin II or our sensitivity to this hormone is elevated. It is therefore crucial that we understand how angiotensin II works and how its actions in the body are mediated. For angiotensin II to act it must first bind to a receptor. Receptors are proteins and behave like locks that are opened by the hormone keys. Thus, cellular receptors for angiotensin II are engaged and activated by increases in angiotensin II in our blood. These receptors then produce signals which initiate a response (e.g. constriction of a blood vessel). Subsequently, the receptors are switched-off to prevent over-stimulation. The experiments proposed in this application continue our investigations into how angiotensin II receptors are switched-on and -off. A major way for receptors to be turned on is for them to interact with other cellular proteins, although we know only some of these interactions for the angiotensin receptor. Receptors are turned off by being ear-marked by a modification known as phosphorylation; these modified receptors are then bound by proteins termed arrestins, which as indicated by their name, play a role in preventing further receptor signalling. These arrestins also help to remove activated receptors from the cell surface to the inside of the cell. This application proposes new technologies to investigate the spectrum of proteins recruited to the angiotensin receptor and the role of arrestins in switching receptors on and off. Results from these studies will further our understanding of angiotensin II receptors and their role in cardiovascular control.Read moreRead less
Structure-function And Domain Minimization Of Insulin-like Peptide 3, A Novel Member Of The Insulin Superfamily.
Funder
National Health and Medical Research Council
Funding Amount
$288,000.00
Summary
Insulin-like peptide 3 (INSL3) is a peptide hormone that is structurally similar to insulin. It is produced in both the testes and the ovaries. In the male, one of its primary roles is to initiate testes descent during fetal development via a direct action on the gubernaculum ligament. Failure of INSL3 action either directly or due to receptor malfunction causes cryptorchidism (undescended testes), one of the most common congenital defects. In the female, INSL3 is implicated in follicle selectio ....Insulin-like peptide 3 (INSL3) is a peptide hormone that is structurally similar to insulin. It is produced in both the testes and the ovaries. In the male, one of its primary roles is to initiate testes descent during fetal development via a direct action on the gubernaculum ligament. Failure of INSL3 action either directly or due to receptor malfunction causes cryptorchidism (undescended testes), one of the most common congenital defects. In the female, INSL3 is implicated in follicle selection. More recent evidence shows that the peptide has clear roles in modulating male and female germ cell maturation. These effects indicate that agonists and antagonists of INSL3 have potential as specific drugs for novel contraceptive approaches or infertility treatments in both sexes. The actions of INSL3 are mediated by interaction with a G-protein coupled receptor known as LGR8. This receptor is expressed in the testes and ovary as well as several other tissues including the brain. However, very little is known about how INSL3 interacts with LGR8 to produce its physiological responses. Consequently, we will determine the structural features of the peptide that are responsible for receptor binding. This will be achieved by use of chemical peptide synthesis of not only INSL3 but also of analogues of the peptide that contain modified residues or domains. These will be assayed for characteristic INSL3 activity and the results, together with those acquired by modern biomolecular interaction analyses, will be used to identify the receptor binding regions for INSL3. This information, together with a determination of the three-dimensional structure of INSL3 by using NMR spectroscopy, will then be disseminated using computer-assisted molecular modelling to design smaller, more stable, orally active analogues. Such mimetics of reduced size that are correspondingly cheaper and simpler to prepare and handle will have great potential for therapeutic regulators of human fertility.Read moreRead less
Helix VIII Of G Protein Coupled Receptors Is A Lipid-activated Signalling Sensor
Funder
National Health and Medical Research Council
Funding Amount
$389,250.00
Summary
G protein-coupled receptors (GPCRs) are the largest superfamily of membrane-embedded receptors and represent prime targets for drug development. The molecular basis for their activation and regulation is poorly understood, particularly the contribution of the membrane environment to receptor function. Using a range of molecular and biophysical approaches and the angiotensin receptor as a model GPCR, studies are proposed to understand the role of the cell membrane in GPCR activation. The results ....G protein-coupled receptors (GPCRs) are the largest superfamily of membrane-embedded receptors and represent prime targets for drug development. The molecular basis for their activation and regulation is poorly understood, particularly the contribution of the membrane environment to receptor function. Using a range of molecular and biophysical approaches and the angiotensin receptor as a model GPCR, studies are proposed to understand the role of the cell membrane in GPCR activation. The results will provide important new information on the molecular mechanism of GPCR regulation and exciting new approaches for drug design.Read moreRead less