Protein Tyrosine Phosphatases In The Regulation Of Insulin Receptor Signalling And Glucose Uptake
Funder
National Health and Medical Research Council
Funding Amount
$425,250.00
Summary
The key pathological feature of type II diabetes is the lack of cellular response to normal levels of circulating insulin. Insulin binding to its cell surface transmembrane receptor initiates a cascade of events known as cellular signalling that results in amongst other things in the uptake of glucose. Protein tyrosine phosphatases (PTPs) are key negative regulators of insulin-induced signalling events and their inhibition with broad based chemical inhibitors can mimic several actions of insulin ....The key pathological feature of type II diabetes is the lack of cellular response to normal levels of circulating insulin. Insulin binding to its cell surface transmembrane receptor initiates a cascade of events known as cellular signalling that results in amongst other things in the uptake of glucose. Protein tyrosine phosphatases (PTPs) are key negative regulators of insulin-induced signalling events and their inhibition with broad based chemical inhibitors can mimic several actions of insulin and lower blood glucose levels in both normal and diabetic rats. This proposal will examine the roles of PTPs and in particular TCPTP and PTP1B in insulin receptor-mediated signalling and glucose uptake. Moreover we will explore the role of TCPTP in alternate insulin receptor-independent processes for glucose uptake. Our studies will shed light on processes important for the regulation of glucose uptake. Moreover our studies may lead to the development of drugs capable of inhibiting PTPs such as TCPTP, that may allow for enhanced glucose uptake and have therapeutic use in the treatment of type II diabetes.Read moreRead less
Regulation And Function Of The Protein Tyrosine Phosphatase TCPTP In Mitosis
Funder
National Health and Medical Research Council
Funding Amount
$455,250.00
Summary
The cell cycle is a universal process by which cells reproduce and it underlies the growth and development of all living organisms. The most important events of the cell cycle concern the replication of chromosomal DNA during S phase and the separation of replicated DNA into progeny cells at mitosis. Mitosis is morphologically the most dynamic phase of the cell cycle and involves the precise coordination of many processes that are governed by reversible protein phosphorylation. Protein phosphata ....The cell cycle is a universal process by which cells reproduce and it underlies the growth and development of all living organisms. The most important events of the cell cycle concern the replication of chromosomal DNA during S phase and the separation of replicated DNA into progeny cells at mitosis. Mitosis is morphologically the most dynamic phase of the cell cycle and involves the precise coordination of many processes that are governed by reversible protein phosphorylation. Protein phosphatases play an important role in reversible protein phosphorylation and they are essential for mitosis. This grant proposal is focused on understanding the regulation and function of protein phosphatases in mitosis. Our studies will provide novel insight into processes mediating mitosis and may lead to the development of alternative strategies for treating cancer.Read moreRead less
Identification And Characterization Of Substrates Of Tyrosine Kinases Involved In Hematopoiesis And Leukemia
Funder
National Health and Medical Research Council
Funding Amount
$241,527.00
Summary
The development and maintenance of tissues in mammals are tightly controlled and complex processes involving the growth, maturation and survival of vast numbers of cells of various types. In cancer, the cell's capacity to faithfully regulate these processes is diminished or lost. Many of the proteins that are essential for growth control are produced by an important class of genes called proto-oncogenes; literally, the prototypes of cancer-causing genes. Naturally occurring mutations in these ge ....The development and maintenance of tissues in mammals are tightly controlled and complex processes involving the growth, maturation and survival of vast numbers of cells of various types. In cancer, the cell's capacity to faithfully regulate these processes is diminished or lost. Many of the proteins that are essential for growth control are produced by an important class of genes called proto-oncogenes; literally, the prototypes of cancer-causing genes. Naturally occurring mutations in these genes have been identified in man and are likely to play a major role in the initiation and progression of distinct human malignancies. A significant number of proto-oncogenes are enzymes called protein tyrosine kinases (PTKs). Research has shown that the function of PTKs is to relay growth signals or other regulatory signals from the outer surface of the cell to specific target proteins inside the cell. These target proteins are needed to relay the signal to other target molecules and so on. This highly ordered process, involving a specific sequence of proteins, ensures that cells respond appropriately to a given signal. Our research focuses on identifying and studying the immediate targets of PTKs with the broad aim of understanding how PTKs control growth in normal and cancerous cells. We have recently developed a method that has enabled us to identify a new protein that may regulate the growth of blood cells. The research proposed here aims to extend our preliminary observations showing that the growth of specific types of blood cells is inhibited by this protein. We also plan to search for new targets of a PTK that is involved in leukemia. The findings of this research will provide important insight into how blood cells are regulated in health and disease.Read moreRead less
Tyrosine Kinases And Phosphatases In Cell Cycle Checkpoint Responses
Funder
National Health and Medical Research Council
Funding Amount
$513,946.00
Summary
In order for an organism to grow and develop, the cells that make up the tissues and organs need to undergo a process of cellular division, wherein individual cells grow and then divide into two cells. During this process of cellular growth and division the entire genome needs to be duplicated (this occurs during S-phase) and then divided equally into the two daughter cells. In S-phase several so-called 'checkpoint' mechanisms exist which ensure that this occurs in an orderly and precise manner. ....In order for an organism to grow and develop, the cells that make up the tissues and organs need to undergo a process of cellular division, wherein individual cells grow and then divide into two cells. During this process of cellular growth and division the entire genome needs to be duplicated (this occurs during S-phase) and then divided equally into the two daughter cells. In S-phase several so-called 'checkpoint' mechanisms exist which ensure that this occurs in an orderly and precise manner. The so-called 'DNA replication checkpoint' delays S-phase progression in response to 'replication stresses' that may otherwise cause DNA damage. Protein tyrosine kinases (PTKs) are hyperactivated in many human solid tumours and blood malignancies contributing to varied aspects of tumour progression. Our preliminary studies indicate that the inactivation of PTKs by protein tyrosine phosphatases may be essential for the suppression of S-phase progression in response to replication stress. Our goal is to understand the molecular mechanisms by which PTKs and tyrosine phosphatases contribute to S-phase checkpoints. Our studies will provide important insights into DNA replication stress-induced checkpoint responses in mammals and identify unprecedented mechanisms by which hyperactivated PTKs may contribute to tumour development.Read moreRead less
Functional Characterization Of A Signaling Complex Between Receptor Protein Tyrosine Phosphatase-k And E-cadherin.
Funder
National Health and Medical Research Council
Funding Amount
$227,036.00
Summary
Contact between cells in the body controls many aspects of cellular function, including cell adhesion, cell movenments, and the architecture of organs. These contacts involve many different kinds of molecules, such as adhesion molecules, proteins that link the cell surface to the cytoskeleton, and many signaling molecules that participate in cellular recognition. It has become increasingly clear that these different molecules interact with one another and that these interactions are functionally ....Contact between cells in the body controls many aspects of cellular function, including cell adhesion, cell movenments, and the architecture of organs. These contacts involve many different kinds of molecules, such as adhesion molecules, proteins that link the cell surface to the cytoskeleton, and many signaling molecules that participate in cellular recognition. It has become increasingly clear that these different molecules interact with one another and that these interactions are functionally important. In this proposal we will study the association between a signaling molecule, the receptor tyrosine phosphatase RPTPk, and a cell-cell adhesion molecule, E-cadherin. RPTPk removes phosphate molecules from tyrosines, an important event that controls many signaling processes; E-cadherin is a major adhesion molecule responsible for cell-cell contact and patterning, and whose dysfunction is involved in tumor invasion. My collaborators and I have recently demonstrated that RPTPk and E-cadherin bind to one another, but the function of this association is unclear. I will test the general hypothesis that these molecules form a signaling complex, that can regulate both the activity of RPTPk and the adhesive function of E-cadherin to ultimately control the way in which cells associate with one another. This work will make an important contribution to our understanding of how cells signal to one another, and provide insights into how cell-cell adhesion and recognition may be perturbed in disease conditions, such as tumor progression.Read moreRead less