Insulin resistance (the inability of ordinarily insulin-sensitive tissues such as muscle and adipose tissue to respond to insulin) contributes to a number of diseases including diabetes and obesity. A key metabolic step in these tissues is the uptake of glucose from the blood stream. This step is accelerated by insulin thus allowing efficient clearance of glucose from the bloodstream after a meal. Our laboratory has played a major role in showing that insulin regulates glucose uptake into muscle ....Insulin resistance (the inability of ordinarily insulin-sensitive tissues such as muscle and adipose tissue to respond to insulin) contributes to a number of diseases including diabetes and obesity. A key metabolic step in these tissues is the uptake of glucose from the blood stream. This step is accelerated by insulin thus allowing efficient clearance of glucose from the bloodstream after a meal. Our laboratory has played a major role in showing that insulin regulates glucose uptake into muscle and adipose tissue by stimulating the movement of a glucose transport protein from inside the cell to the cell surface (see http:--www.imb.uq.edu.au-groups-james-glut4 for an animated description of this process). The purpose of this proposal is to dissect the molecular mechanisms by which this glucose transporter can be held inside the cell in the absence of insulin and then allowed to be released from this site moving to the surface in the presence of insulin. Our studies over the past 5 years have brought us much closer to understanding this process in detail. The identification of the molecules responsible for this regulatory step will not only aid our understanding of this process but it will also provide a valuable target for development of therapeutic agents that can be used to combat insulin resistance.Read moreRead less
Macrophages are white blood cells that provide front line defence against infection by initiating inflammatory responses by ingesting or phagocytosing microbes and by releasing soluble messengers (cytokines) to recruit other immune cells. These defensive functions require extensive trafficking of proteins within the macrophages. Protein trafficking is orchestrated in part by a family of membrane fusion proteins called SNAREs. By defining the relevant SNAREs, we have recently discovered a much ac ....Macrophages are white blood cells that provide front line defence against infection by initiating inflammatory responses by ingesting or phagocytosing microbes and by releasing soluble messengers (cytokines) to recruit other immune cells. These defensive functions require extensive trafficking of proteins within the macrophages. Protein trafficking is orchestrated in part by a family of membrane fusion proteins called SNAREs. By defining the relevant SNAREs, we have recently discovered a much acclaimed and novel pathway that allows efficient, combined cytokine secretion and phagocytosis in macrophages. Our studies proposed here will now expand on this discovery by comparing the phagocytic process, in terms of SNARE-mediated membrane and cytokine trafficking, for a wide range of microbes, highlighting differences that could provide new avenues for drug development. Moreover, since our strategy of using SNAREs to investigate and map trafficking pathways has proven so successful, we will now launch a major large-scale initiative to study ALL SNARE-mediated trafficking pathways in macrophages using a discovery pipeline of assays, including live cell imaging, we have developed. This will provide valuable information on many SNAREs including those associated with disease, and will elucidate trafficking pathways governing all macrophage actions in immunity, including cytokine secretion and antigen presentation. All of these pathways are highly relevant to current drug targets being used clinically or studied in inflammatory disease and for the development of vaccines.Read moreRead less