Novel Mechanisms In Regulating Cytokine Secretion In The Inflammatory Response
Funder
National Health and Medical Research Council
Funding Amount
$323,160.00
Summary
Macrophages are key cells in the immune and inflammatory response. They play a role in many biological processes including wound healing and resistance to tumours and infections. It is also a major cell involved in mediating inflammation and tissue damage in chronic inflammatory diseases such as atherosclerosis and rheumatoid arthritis. The macrophage's role in these processes is achieved in large part by secreting enzymes and other proteins called cytokines to the outside of the cell. These cyt ....Macrophages are key cells in the immune and inflammatory response. They play a role in many biological processes including wound healing and resistance to tumours and infections. It is also a major cell involved in mediating inflammation and tissue damage in chronic inflammatory diseases such as atherosclerosis and rheumatoid arthritis. The macrophage's role in these processes is achieved in large part by secreting enzymes and other proteins called cytokines to the outside of the cell. These cytokines are synthesized by the macrophage and travel through a secretory pathway in the cell, in order to be released to the outside of the cell. There are various quality control mechanisms along the pathway which ensure only correctly made functional protein is secreted out of the cell. One cytokine, called macrophage inhibitory cytokine is produced by the immune cells called macrophages only when they become activated to mount an immune response against invading pathogens. The cell uses a novel mechanism to ensure the quality control of this cytokine. The propeptide of this cytokine targets incorrectly folded cytokine to a protein complex called the proteasome for degradation. This prevents secretion of inactive cytokine. Additionally, the propeptide of the cytokine helps secretion from macrophages by a novel mechanism. Because of these characteristics the cytokine provides a good model to study secretion from macrophages under pro- and anti-inflammatory conditions. In addition, demonstrating that activation of the macrophages causes a major upregulation in the synthesis and secretion of cytokines by novel mechanisms, will further our understanding of how the macrophage operates in fulfilling its role in the immune response.Read moreRead less
Molecular Determinants Of Amino Acid-dependent Signalling By The Calcium-sensing Receptor
Funder
National Health and Medical Research Council
Funding Amount
$566,035.00
Summary
Amino acids are the building blocks of proteins and an alternative energy source to carbohydrate and fat. Proteins are major structural components of our bodies. They also fulfil an amazing diversity of cellular and bodily functions acting, for example, as enzymes (biological catalysts), receptors, molecular chaperones and biological machines. Thus, amino acids are key nutrients and the human body has developed mechanisms for tightly regulating cellular responses depending upon their levels in b ....Amino acids are the building blocks of proteins and an alternative energy source to carbohydrate and fat. Proteins are major structural components of our bodies. They also fulfil an amazing diversity of cellular and bodily functions acting, for example, as enzymes (biological catalysts), receptors, molecular chaperones and biological machines. Thus, amino acids are key nutrients and the human body has developed mechanisms for tightly regulating cellular responses depending upon their levels in blood. Identifying amino acid sensing molecules and identifying the mechanisms they use to control cellular responses is thus a key issue in human biology. The applicant identified the calcium-sensing receptor as an amino acid sensor and has shown that this receptor provides a means by which fluctuations in amino acid levels regulate the secretion of the key calcium-regulating hormone, PTH. In the current proposal, the mechanisms that link amino acid activation of the calcium-sensing receptor to its key cellular responses will be determined.Read moreRead less