Characterization Of 72 And 52 KDa Inositol Polyphosphate 5-phosphatases: Role In Vesicular Trafficking And Cell Death
Funder
National Health and Medical Research Council
Funding Amount
$408,055.00
Summary
Cells respond to the external environment, stress, hormones and grow th factors by generating messages inside the cell that send a signal to the nucleus that stimulates cell growth. One such signalling network is that produced by membrane lipids known as phosphoinositides. Enzymes or kinases that modify these membrane lipids in particular an enzyme known as the PI 3-kinase generate potent signalling molecules that regulate cell growth. It has been shown by many studies that signals generated by ....Cells respond to the external environment, stress, hormones and grow th factors by generating messages inside the cell that send a signal to the nucleus that stimulates cell growth. One such signalling network is that produced by membrane lipids known as phosphoinositides. Enzymes or kinases that modify these membrane lipids in particular an enzyme known as the PI 3-kinase generate potent signalling molecules that regulate cell growth. It has been shown by many studies that signals generated by the PI 3-kinase are amplified in certain human cancers. Inherited cancer syndromes have been described in which the cell has lost the ability to switch off these lipid messenger molecules. The current project aims to investigate two recently identified enzymes called 5-phosphases that have the ability to terminate PI 3-kinase membrane signals. Both these enzymes were isolated and characterized by the host laboratory and it is predicted they will play distinct roles in the cell. The 72 kDa 5-phosphatase is predicted to regulate protein and vesicular trafficking to the surface of cell. This proposal aims to investigate if the 72 kDa 5-phosphatase can regulate the intracellular sorting of new proteins within the cell. We have also noted the 72 kDa 5-phosphatase may play a role in the development of the nervous system in particular the ability of nerves to send branches out and differentiate. This proposal will investigate this hypothesis. The second enzyme that we have isolated is a 52 kDa 5-phosphatase. This enzyme is present in many cells. We have compelling evidence that the enzyme forms a complex with a recently decribed protein called SODD that stops cells from dying in response to inappropropirate signals. We predict the 52 kDa 5-phosphatase may function to prevent prolonged cell survival as is observed in cancer. We will investigate if this enzyme regulates the cell death pathway and if increased or decreased levels of the 52 kDa 5-phosphatase alter cell survivalRead moreRead less
Regulation Of The Quality Of DNA Repair By Timing In The Cell Cycle
Funder
National Health and Medical Research Council
Funding Amount
$468,794.00
Summary
During responses to infection or immunisation, antibody-producing _B� cells mutate their antibody genes at extreme rates. Rare mutations which improve the antibodies are selected by competition between B cells favouring those which make the best antibodies: Darwinian evolution on extreme _fast-forward�. We aim to understand this process because it is essential for normal immunity and effective vaccination, and because when it goes wrong, it can cause aggressive human cancers.
Multi-domain Regulation Of DNA Damage Response Kinases
Funder
National Health and Medical Research Council
Funding Amount
$313,427.00
Summary
DNA damage plays a key role in the onset of cancer and the response to cancer therapies. Mutations in the Chk2 DNA damage response kinase are associated with increased cancer risk. We will study detailed mechanisms how phosphorylation of Chk2-like kinases contributes to normal copying of our DNA every time a cell divides, and how it regulates how Chk2 is activated. The studies will improve our understanding how cancer may originate and how cancer cells respond to chemo- or radiation therapy.