Fission, Fusion And Distribution Of Mitochondria In Mammalian Cells
Funder
National Health and Medical Research Council
Funding Amount
$480,750.00
Summary
Mitochondria are small cellular compartments that produce most of the cell's energy in the form of ATP. Mitochondria were once thought of as small bean-shaped organelles floating around in the cell, however it has become clear that this is not the case. Mitochondria are found as a network of tubules radiating from around the nucleus and they undergo constant changes in their shape through both fission and fusion events. Mitochondria are transported along microtubules which act as highways in the ....Mitochondria are small cellular compartments that produce most of the cell's energy in the form of ATP. Mitochondria were once thought of as small bean-shaped organelles floating around in the cell, however it has become clear that this is not the case. Mitochondria are found as a network of tubules radiating from around the nucleus and they undergo constant changes in their shape through both fission and fusion events. Mitochondria are transported along microtubules which act as highways in the cell so that they can be distributed to areas that require ATP or other functions particular to mitochondria such as their ability to regulate the release of calcium. In specialist cells, mitochondria are organised even further. Sperm cells contain mitochondria packed around the mid-piece of the flagellum so that ATP can be utilised directly for swimming. Mitochondria are also highly organised in muscle cells to supply ATP for movement while in pancreatic cells mitochondria at the cell's edge help to regulate the secretion of molecules such as insulin into the bloodstream. While we are beginning to understand the great importance of mitochondria to the cell, we are yet to work out how these organelles undergo the drastic morphological changes which are essential for cellular function. In this application, we plan to identify and characterise the proteins involved in the division of mitochodria and the movement of these organelles along the microtubule highways. Understanding the basic mechanisms of mitochondrial dynamics in tissue culture cells will provide valuable insights into mitochondrial segregation and specialisation in differentiated cells such as sperm, nerve, muscle and pancreatic cells, where such events are crucial for function.Read moreRead less
Transcriptional Complexes In Haematopoiesis And T-cell Leukemia
Funder
National Health and Medical Research Council
Funding Amount
$557,939.00
Summary
Childhood T-cell leukemias have a poor prognosis for recovery. We are determining, with atomic level precision, how the proteins LMO2 (also linked to prostate and other cancers) and Tal1, and their binding partners contribute to both normal blood cell development and T-cell leukemia. With this information we are developing reagents that can be used to disrupt disease-causing complexes, and which will lead towards the development of new, specific, therapeutics for leukemias and other cancers.
Throughout our lives cells must die and be replenished. One way multicellular organisms remove unwanted cells is through a process called programmed cell death. This process eliminates redundant, damaged or infected cells by a program of cell suicide. We are studying the underlying molecular mechanisms of this cell suicide in order to design new pharmaceuticals to treat illnesses caused by a disruption in programmed cell death. The fine balance between living and dying cells must be maintained a ....Throughout our lives cells must die and be replenished. One way multicellular organisms remove unwanted cells is through a process called programmed cell death. This process eliminates redundant, damaged or infected cells by a program of cell suicide. We are studying the underlying molecular mechanisms of this cell suicide in order to design new pharmaceuticals to treat illnesses caused by a disruption in programmed cell death. The fine balance between living and dying cells must be maintained and if this balance is lost then disease may result. A reduced level of cell death may result in cancers while too many dying can contribute to degenerative diseases such as Alzheimer's disease and stroke. Currently many of these diseases do not have effective treatments. We will determine the three-dimensional structures of key proteins involved in programmed cell death and use this information to design drugs that can interfere with the molecular processes involved in signalling cell death. Such drugs may prove useful new therapies in a wide range of diseases caused by a breakdown in the biochemical paths to cell death.Read moreRead less
Inhibition Of Retinoblastoma Protein Degradation By Interaction With The Serpin PAI-2 Via A Novel Consensus Motif
Funder
National Health and Medical Research Council
Funding Amount
$463,500.00
Summary
Plasminogen activator inhibitor-2 (PAI-2) has previously been shown to inhibit the activity of enzymes outside the cell that are involved in blood clotting and cell migration. We have discovered that this activity is probably not the major role of PAI-2. PAI-2 also has a function inside cells that protect and increases the activity of an important tumour suppressor protein called the retinoblastoma tumour suppressor protein (Rb). Rb is involved in many cellular functions such as, cell death, cel ....Plasminogen activator inhibitor-2 (PAI-2) has previously been shown to inhibit the activity of enzymes outside the cell that are involved in blood clotting and cell migration. We have discovered that this activity is probably not the major role of PAI-2. PAI-2 also has a function inside cells that protect and increases the activity of an important tumour suppressor protein called the retinoblastoma tumour suppressor protein (Rb). Rb is involved in many cellular functions such as, cell death, cell differentiation, cell growth, and most importantly prevention of cancer development. Rb is attacked and destroyed by several viruses which causes cells to become cancerous. This grant seeks to fully understand how PAI-2 protects and interacts with Rb. We have already found a new site on Rb to which PAI-2 binds. This site is also used by other proteins in the cell as well as disease causing virus proteins. Examples of these proteins are BRCA1, a protein involved in breast cancer development, and EBNA6, a protein from Epstein Barr virus that causes glandular fever and tumours. We have also found, and seek to explore further, how PAI-2 reverses the activities of the cervical cancer causing proteins of the human papilloma virus. Although at an early stage, these studies may lead to the development of new therapeutic drugs based on PAI-2 for the treatment of various types cancers or warts caused by HPV. Analysing the activity of PAI-2 inside cells will have implications for understanding much of the confusing scientific literature on PAI-2 and will provide a better comprehension of the role of PAI-2 in inflammation, cell differentiation, wound healing and cancer. For example it has long been known that the presence of PAI-2 in cancerous tumours is linked with a better prognosis, an activity that can now be understood in terms of the PAI-2 interaction with Rb. This new understanding may lead to the development of PAI-2 based prognostic assays for cancer.Read moreRead less
Characterising The Role Of MID1 In X-linked Opitz Syndrome: Implications For CATCH22 And Related Disorders
Funder
National Health and Medical Research Council
Funding Amount
$211,527.00
Summary
Opitz syndrome is a debilitating genetic disorder which affects the normal development of many organs and tissues of the human embryo. Patients with Opitz syndrome commonly present with facial deformities (such as cleft lip and palate) as well as both genital and heart defects. Males are usually more severely affected than females although the severity of the disease can vary even amongst males of the same family. Patients can die suddenly in infancy or suffer further developmental impairment du ....Opitz syndrome is a debilitating genetic disorder which affects the normal development of many organs and tissues of the human embryo. Patients with Opitz syndrome commonly present with facial deformities (such as cleft lip and palate) as well as both genital and heart defects. Males are usually more severely affected than females although the severity of the disease can vary even amongst males of the same family. Patients can die suddenly in infancy or suffer further developmental impairment due to respiratory complications and swallowing difficulties that result from the significant facial deformities. A brighter outlook for patients is expected if early and often repeated surgical repair is undertaken to correct not only the facial deformities but also any heart and genital abnormalities. Our research laboratory has recently identified the gene that, when mutated, causes one form of Opitz syndrome. Defects in this gene account for around half the cases with the disorder. Evidence suggests that there may be a number of other genes involved in causing the remaining cases of the disease. The proposed research is aimed at investigating the molecular and developmental mechanisms that go awry as a result of the gene mutation. It is anticipated that these studies will provide valuable scientific knowledge about why some patients are more severely affected than others as well as offering clues to the identity of the genes that cause the remaining cases of Opitz syndrome. The results also have potentially important implications for the understanding of other diseases that show similar deformities. The knowledge gained from this research is expected to provide a valuable aid for effective genetic counselling (as well as the option of prenatal diagnosis) for families at risk of further affected pregnancies. This will also ultimately lead to more effective disease management and correction in the affected child.Read moreRead less
G2 Phase Cdk2/cyclin A Co-ordinates Multiple Pathways In G2/M Progression
Funder
National Health and Medical Research Council
Funding Amount
$302,036.00
Summary
Cell growth is a tightly regulated process that ensures the exact duplication of the entire genomic DNA followed by division of the cell into two identical daughter cells. If this strict ordering of events is in any way disrupted, the resultant daughter cells would have a different complement of DNA from their parent cell, essentially mutant cells. The cell has established a mechanism to ensure the correct ordering of these crucial events, known as the cell cycle, and mechanisms that can respond ....Cell growth is a tightly regulated process that ensures the exact duplication of the entire genomic DNA followed by division of the cell into two identical daughter cells. If this strict ordering of events is in any way disrupted, the resultant daughter cells would have a different complement of DNA from their parent cell, essentially mutant cells. The cell has established a mechanism to ensure the correct ordering of these crucial events, known as the cell cycle, and mechanisms that can respond to disruptions in this ordering and halt the normal cell cycle mechanism until the fault is rectified. These are the checkpoint controls. Checkpoint controls also respond to environmental stresses such as toxins that can damage the DNA to produce mutations. In diseases such as cancer, these checkpoint mechanisms are often faulty, allowing the cells to accumulate DNA mutations which can ultimately result in the cells becoming the aggresive, malignant tumours associated with the worst forms of this disease. Thus a detailed understanding of the cellular mechanisms involved in normal cell cycle and checkpoint control is important in not only defining the causes of these diseases at a molecular level, but may ultimately provide molecular targets for drugs that specifically destroy cancer cells by targeting the faulty checkpoint control. This proposal will investigate one component of the cell cycle mechanism, cdk2-cyclin A, which also has a major role in checkpoint control, to determine its exact role in both these important cellular growth controls.Read moreRead less
ISG60, A Novel Interferon-induced Protein: Cell Growth Inhibitory Actions
Funder
National Health and Medical Research Council
Funding Amount
$197,030.00
Summary
The interferons are signaling molecules produced by cells as part of an early warning sytsem to alert nearby tissue cells and immune cells to defend themselves against an impending viral attack or aberrant growth of cells. We have discovered ISG60, a new member of a group of proteins called the ISG54 family. The production of this family of proteins is turned on in all cells responding to the interferons. Exactly what the members of the protein family do within cells remains to be established. H ....The interferons are signaling molecules produced by cells as part of an early warning sytsem to alert nearby tissue cells and immune cells to defend themselves against an impending viral attack or aberrant growth of cells. We have discovered ISG60, a new member of a group of proteins called the ISG54 family. The production of this family of proteins is turned on in all cells responding to the interferons. Exactly what the members of the protein family do within cells remains to be established. However, by preparing cells which produce the ISG60 protein, we have found that it severely affects their growth, slowing the growth rate down and making the cells divide abnormally to become large, containing many nuclei and others dying. We propose that ISG60 binds to the structures involved in cell division and we have preliminary evidence that ISG60 interacts with an important protein involved in cell regulation, the retinoblastoma protein (pRb). The aim of this project is to more fully understand the role of ISG60 in cells. In particular, we aim to determine if ISG60 interacts with other important proteins inside cells. We shall explore the relationship of ISG60 function inside cells in greater detail as it should provide new insight into ways in which cell growth is regulated. This study will also provide insight into how the slowing of cell growth makes the cells less suitable for viral infection and reproduction, as well as providing new approaches for preventing the growth of cancer cells.Read moreRead less
Identification of Proteins that Regulate Apoptosis Through Interaction With IAPS. Apoptosis is the process by which multicellular organisms eliminate unwanted cells. Identifying proteins involved in cell death regulation is central to our understanding of disease states arising from aberrations in this process. The mammalian protein DIABLO, promotes cell death by interacting with and antagonising inhibitor of apoptosis proteins (IAPS). Given the existence of several IAP regulatory proteins (IRPs ....Identification of Proteins that Regulate Apoptosis Through Interaction With IAPS. Apoptosis is the process by which multicellular organisms eliminate unwanted cells. Identifying proteins involved in cell death regulation is central to our understanding of disease states arising from aberrations in this process. The mammalian protein DIABLO, promotes cell death by interacting with and antagonising inhibitor of apoptosis proteins (IAPS). Given the existence of several IAP regulatory proteins (IRPs) in insects, other mammalian IRPs probably also exist. These may be of equal importance in regulating apoptosis, especially in tissues where DIABLO is not expressed. The main aim of the proposed study is to idenitify and characterise other IRPs in mammalian cells.Read moreRead less