Analysis Of Intracellular Signalling And Biological Activities Of The GM-CSF Receptor Family Using Constitutive Mutants
Funder
National Health and Medical Research Council
Funding Amount
$505,699.00
Summary
The cytokines GM-CSF, IL-3 and IL-5 stimulate the growth and actions of a wide range of blood cells. Each binds to a receptor on the cell surface which then triggers the generation of a number of signals inside the cell; it is these signals that are responsible for the cytokine?s actions. We have previously generated a panel of constitutive mutant forms of the beta subunit which is shared by the GM-CSF, IL-3 and IL-5 receptors. These constitutive mutants trigger signals even in the absence of th ....The cytokines GM-CSF, IL-3 and IL-5 stimulate the growth and actions of a wide range of blood cells. Each binds to a receptor on the cell surface which then triggers the generation of a number of signals inside the cell; it is these signals that are responsible for the cytokine?s actions. We have previously generated a panel of constitutive mutant forms of the beta subunit which is shared by the GM-CSF, IL-3 and IL-5 receptors. These constitutive mutants trigger signals even in the absence of the cytokine; importantly, the different mutants appear to trigger only a subset of the signals generated by the normal receptor. The aim of this project is to use our panel of constitutive beta subunit mutants to determine how the GM-CSF, IL-3 and IL-5 receptors generate signals inside the cell and how these signals lead to the various biological actions of the receptors on blood cell growth and maturation. Findings from this research will be relevant to the understanding and treatment of diseases which involve abnormal growth or function of blood cells such as leukaemia and inflammatory diseases.Read moreRead less
The Role Of Plasma Membrane Microdomains In Regulating Ras-dependent Raf Activation
Funder
National Health and Medical Research Council
Funding Amount
$216,100.00
Summary
In human cancers one or more of the signaling pathways leading from growth factor receptors at the cell surface to the nucleus where cell division is initiated are subverted. For example, a protein called Ras, that regulates a series of major signaling pathways, is mutated in 25% of all human tumours. This leaves Ras and the signaling pathways permanently switched on causing uncontrolled cell proliferation. Our previous work has demonstrated that Ras must be attached to the inner surface of the ....In human cancers one or more of the signaling pathways leading from growth factor receptors at the cell surface to the nucleus where cell division is initiated are subverted. For example, a protein called Ras, that regulates a series of major signaling pathways, is mutated in 25% of all human tumours. This leaves Ras and the signaling pathways permanently switched on causing uncontrolled cell proliferation. Our previous work has demonstrated that Ras must be attached to the inner surface of the cell membrane in order to function properly. This project now seeks to understand exactly how Ras attaches to and interacts with specific sites in the plasma membrane. Its is becoming clear that different isoforms of Ras, called H-, N- and K-ras have different functions in the cell which may in turn result from their different sites of attachment to the cell membrane. This is important because by understanding the precise micro-environment in which the different Ras proteins operate and how they activate subsequent proteins in their signaling networks we will be in a good position to design drugs that selectively compromise the function of each specific Ras isoform. A highly relevant example is provided by K-ras which is mutated in 90% of all pancreatic cancers and 50% of all colon cancers. Clearly the clinical impact of a drug that could selectively neutralise K-Ras function in these tumours is potentially enormous.Read moreRead less
The project aims to understand how a factor responsible for the production of a type of white blood cell interacts with its receptor. If we knew the molecular details of how this factor works then we would be able to control better diseases, such as osteoporosis and arthritis, where such cells can play havoc by destroying tissue. The project also has implications for certain leukaemias which lose growth control mechanisms in response to this factor.
The regulated movement of membrane receptors and ligands between the cell surface and intracellular compartments is vital to many cellular operations, including communication between cells and their environment. However, the molecular details of these sorting events remain poorly defined. Determination of the mechanisms that control the cellular distribution of receptors is critical for understanding normal cellular processes and in pathological processes like tumorigenesis.