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
Defining The Role And Contribution Of Cdc37 To Signal Transduction And Tumourigenesis By Src-family Kinases
Funder
National Health and Medical Research Council
Funding Amount
$411,430.00
Summary
Cells respond to extracellular stimuli, such as growth factors and hormones, by activating intracellular networks of signaling molecules. It is the activation of these signaling networks that is ultimately responsible for mediating the biological responses of cells to extracellular stimuli (e.g. insulin stimulating glucose metabolism by cells). Members of the Src-family of tyrosine kinases are paramount among signaling molecules, as they are able to directly initiate the activation of a cascade ....Cells respond to extracellular stimuli, such as growth factors and hormones, by activating intracellular networks of signaling molecules. It is the activation of these signaling networks that is ultimately responsible for mediating the biological responses of cells to extracellular stimuli (e.g. insulin stimulating glucose metabolism by cells). Members of the Src-family of tyrosine kinases are paramount among signaling molecules, as they are able to directly initiate the activation of a cascade of signaling networks that regulate the activity of the cell. Significantly though, the inappropriate activation of Src-family kinases has been implicated in the development of cancer, particularly breast and colon cancer, in humans. To fulfill their signaling functions however, Src-family kinases must first be folded into an active conformation upon their synthesis in the cell then be maintained in this conformation. Although previous studies, including our own, have implicated a class of proteins called molecular chaperones in this process, little is known about how the folding of Src-family kinases by these proteins is achieved and regulated. The overall aim of this study is to determine how the folding of Hck, one member of the Src-family of tyrosine kinases, into a conformation that enables it to participate in signaling networks is achieved and regulated. It is expected that the results from this study will provide significant new insight into how this process might influence the ability of cells to respond to extracellular stimuli and potentially contribute to the conversion of a normal cell into one with tumourigenic properties. Findings from this project may be particularly important in the context of human cancer. A better knowledge of how the signaling activity of Src-family kinases is regulated by molecular chaperones might provide a new avenue of investigation for the identification of novel chemotherapeutic agents.Read moreRead less
Regulators Of G Protein Signalling On The Golgi Complex
Funder
National Health and Medical Research Council
Funding Amount
$666,116.00
Summary
The secretion of proteins from cells involves a host of regulatory and signalling proteins. G proteins, signal transducers, located on the Golgi membranes, participate in the budding of transport vesicles in the secretory pathway. A newly-discovered family of Regulators of G Protein Signalling (RGS) proteins perform the critical function of turning off signals generated by G proteins. RGS proteins are powerful, but as yet, ill-defined regulatory molecules. In this study we will identify and char ....The secretion of proteins from cells involves a host of regulatory and signalling proteins. G proteins, signal transducers, located on the Golgi membranes, participate in the budding of transport vesicles in the secretory pathway. A newly-discovered family of Regulators of G Protein Signalling (RGS) proteins perform the critical function of turning off signals generated by G proteins. RGS proteins are powerful, but as yet, ill-defined regulatory molecules. In this study we will identify and characterize RGS proteins in macrophages that are located on Golgi membranes and help to regulate cytokine secretion and other immune functions. More detailed studies on selected RGS proteins will include mutational analysis of functional domains within the proteins and identification of other proteins that interact with RGS proteins. Overall these studies will lead us to understand how specific RGS proteins interact with G proteins and other molecules to regulate signalling in the secretory pathway. Anomalies in cell signalling have severe consequences in a variety of diseases and can cause cancer. Similarly, abnormal secretion in cells contributes to inflammation, diabetes and other disease processes. Information forthcoming from our studies on RGS proteins will have wide-reaching implications and the potential to reveal new targets for therapeutics in these diseases.Read moreRead less
Role Of FHA Domains As Protein-protein Interaction Modules In Cell Signalling
Funder
National Health and Medical Research Council
Funding Amount
$191,973.00
Summary
The proper processing of information in cells involves the association of different proteins to signalling complexes. We will decipher the role the so-called FHA module plays in the formation of protein complexes. FHA modules are present in several proteins that are important for the repair of damaged DNA and the stability of chromosomes. Understanding the structure and function of this module will be relevant for various forms of cancer where DNA is damaged.
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
Structural Characterisation Of Phosphopeptide Recognition By FHA Domains
Funder
National Health and Medical Research Council
Funding Amount
$257,036.00
Summary
Cells require numerous signalling pathways to keep various cellular processes coordinated and under control. One of the most important aspects of signalling is formation of complexes involving two or more different proteins. One of the recently identified players in the formation of these signalling complexes is the so-called forkhead-associated (FHA) module, FHA modules are protein sequences of ~130 amino acids that appear as a part of signalling proteins and bind to specific sequences on signa ....Cells require numerous signalling pathways to keep various cellular processes coordinated and under control. One of the most important aspects of signalling is formation of complexes involving two or more different proteins. One of the recently identified players in the formation of these signalling complexes is the so-called forkhead-associated (FHA) module, FHA modules are protein sequences of ~130 amino acids that appear as a part of signalling proteins and bind to specific sequences on signalling protein partners. Many proteins containing FHA modules are important for the repair of damaged DNA and the stability of chromosomes. The aim of our studies is to understand the molecular and atomic details of how FHA modules bind their partners. This is the first step towards designing therapeutic agents against various forms of cancer where DNA is damaged.Read moreRead less
A Novel Cytokine-receptor Survival Axis In Chronic Myeloid Leukaemia
Funder
National Health and Medical Research Council
Funding Amount
$424,731.00
Summary
Cancer cells grow and survive in an unrestrained manner. Current therapies target cancer growth, however they permit the long-term survival of some cancer cells and increase the possibility of drug resistance and disease relapse. We have identified a new molecular switch that is constitutively activated (unregulated) in leukemia. Targeting specific components of this unregulated cell survival may provide new and improved approaches for the development of therapeutics in the treatment of leukemia
Genetic Approaches To Understand How Imbalanced Cytokine Signalling Drives The Pathogenesis Of Emphysema
Funder
National Health and Medical Research Council
Funding Amount
$519,715.00
Summary
Emphysema is a major component of Chronic Obstructive Pulmonary Disease (COPD), the fifth leading cause of death in Australia for which there is no effective treatment. We have discovered a specific mutation in a gene called gp130 that results in the formation of emphysema in mice. This finding allows us to understand the exact mechanisms by which this mutation causes emphysema, and therefore has the potential to uncover new strategies to design novel therapies against emphysema in humans.
Understanding The Role Of Tec In Fcgamma Receptor Mediated Phagocytosis
Funder
National Health and Medical Research Council
Funding Amount
$211,527.00
Summary
The recognition and destruction of bacterial pathogens and other foreign particles by specific immune cells (macrophages) is principally mediated by the Fcgamma class of cell surface antibody receptors. This proposal aims to understand the molecular mechanisms which link receptor activation to the cellular rearrangements required to invaginate or swallow the offending particle. We have used immunofluorescent microscopy and biochemical methods to show that the intracellular tyrosine kinase Tec is ....The recognition and destruction of bacterial pathogens and other foreign particles by specific immune cells (macrophages) is principally mediated by the Fcgamma class of cell surface antibody receptors. This proposal aims to understand the molecular mechanisms which link receptor activation to the cellular rearrangements required to invaginate or swallow the offending particle. We have used immunofluorescent microscopy and biochemical methods to show that the intracellular tyrosine kinase Tec is an important component of the phagocytosis mechanism. Here we plan to use highly selective gene targeting methods to generate a mouse cell culture model system which is devoid of Tec protein. This will allow us to determine whether Tec is essential for Fcgamma-mediated phagocytosis. Reintroduction of mutant versions of the Tec protein into this null background will provide detailed information on the molecular partners of Tec and the individual roles of the various domains within the Tec protein. By studying the molecular mechanism of phagocytosis, we expect to gain an understanding of how to influence the Fcgamma signalling pathway, either to enhance the ability to deal with pathogens, or to restrict the consequences of excessive phagocytosis associated with autoimmune diseases. Tec is an enzyme likely to play an important role between the Fcgamma receptor and actin cytoskeleton rearrangements and therefore is a potentially important drug target.Read moreRead less