Characterization Of The Novel Drug And Xenobiotic Metabolizing UGT3A Enzyme Family
Funder
National Health and Medical Research Council
Funding Amount
$578,352.00
Summary
The elimination of chemicals made in the body or from environmental sources is essential for the maintenance of good health and the prevention of debilitating diseases. We have discovered two enzymes that use glucose and other sugars to detoxify fat-soluble chemicals. In this project we will study how these enzymes work and how they are regulated in the body. With this knowledge, we may be able to target the processes of drug and chemical detoxification to make them more efficient.
UDP Glucuronosyltransferases As Regulators Of Signaling Pathways Modulated By Chemical Ligands.
Funder
National Health and Medical Research Council
Funding Amount
$500,460.00
Summary
Cells respond to their surroundings by transferring information received at the cell surface to the nucleus leading to changes in gene expression. There are many signaling pathways which transfer this informatrion to the nucleus. Some of these pathways are controlled by small molecules, usually fat-soluble chemicals. As a family of enzymes, the UDP glucuronosyltransferases (UGT) have evolved to eliminate fat-soluble chemicals, we propose that UGTs play a pivotal role in regulating the concentrat ....Cells respond to their surroundings by transferring information received at the cell surface to the nucleus leading to changes in gene expression. There are many signaling pathways which transfer this informatrion to the nucleus. Some of these pathways are controlled by small molecules, usually fat-soluble chemicals. As a family of enzymes, the UDP glucuronosyltransferases (UGT) have evolved to eliminate fat-soluble chemicals, we propose that UGTs play a pivotal role in regulating the concentrations of fat-soluble chemicals involved in signaling, and thus are important in controlling gene expression. We intend to provide evidence for this novel role of UGTs in this project. This information will be used to alter the response of the cell to its environment. For example, to help protect the cell against environmental toxins, or to make a cancer cell more susceptible to a chemotherapeutic agent.Read moreRead less
Molecular Determinants Of UDP Glucuronosyltransferase 1A3 And 1A4 Expression
Funder
National Health and Medical Research Council
Funding Amount
$516,078.00
Summary
Enzymes in the liver and gastrointestinal tract have a crucial role in protecting against the toxic effects of fat-soluble chemicals. Two of these enzymes called UGT1A3 and UGT1A4 have a special role in protecting against drugs and toxins that contain nitrogen groups. The levels of these two enzymes in the liver and gut vary extensively between individuals. In this project we will determine how the levels of these enzymes are controlled and what is the cause of this variability between individua ....Enzymes in the liver and gastrointestinal tract have a crucial role in protecting against the toxic effects of fat-soluble chemicals. Two of these enzymes called UGT1A3 and UGT1A4 have a special role in protecting against drugs and toxins that contain nitrogen groups. The levels of these two enzymes in the liver and gut vary extensively between individuals. In this project we will determine how the levels of these enzymes are controlled and what is the cause of this variability between individuals. This will help us predict those individuals who are more at risk from the adverse effects of nitrogen-containing drugs and from the toxic effects of chemicals in the diet or the environment. This project will also help us develop methods to increase the levels of these protective enzymes and help reduce the effects of exposure to toxic chemicals.Read moreRead less
Probing UDP-glucuronosyltransferase Protein-protein Interactions: The Power Of Two.
Funder
National Health and Medical Research Council
Funding Amount
$482,710.00
Summary
Drugs and other chemicals (eg. dietary constituents, environmental pollutants, and chemicals that occur naturally in the body - such as steroid hormones) are broken down by specialised proteins called enzymes. This process is referred to as biotransformation, or 'metabolism'. Drug and chemical metabolism serves as a detoxification mechanism (since the products of metabolism generally lack biological activity) and as a means of eliminating these substances from the body. UDP-Glucuronosyltransfera ....Drugs and other chemicals (eg. dietary constituents, environmental pollutants, and chemicals that occur naturally in the body - such as steroid hormones) are broken down by specialised proteins called enzymes. This process is referred to as biotransformation, or 'metabolism'. Drug and chemical metabolism serves as a detoxification mechanism (since the products of metabolism generally lack biological activity) and as a means of eliminating these substances from the body. UDP-Glucuronosyltransferase (UGT) is one of the most important enzymes involved in drug and chemical metabolism. Consistent with its ability to metabolise such a large number of compounds, UGT is known to exist as a 'superfamily' of structurally related proteins. Despite the importance of UGT, little is known about the structural characteristics of these enzymes that are responsible for recognising and binding different classes of chemicals. Accumulating evidence from this and other laboratories indicates that the individual UGT proteins may combine with themselves (to form a homodimer) and with other UGT proteins (to form heterodimers). This project largely seeks to define the scope of UGT homo- and hetero- dimerisation, identify the structural elements of the proteins responsible for association and characterise the functional significance of dimerisation. The project will further explore associations between UGTs and other proteins, namely albumin. Characterisation of UGT dimerisation and associations with other proteins is fundamental to our understanding of how this enzyme functions and selects particular chemicals for metabolism. The work also has important implications for the devlopment and interpretation of in vitro (or 'test-tube') approaches for predicting how drugs are metabolised in humans. Such tests are widely employed in research and pharmaceutical company laboratories to predict how the body 'handles' new drugs prior to their administration to humans.Read moreRead less
Structure, Function And Regulation Of Human Cytosolic Sulfotransferases
Funder
National Health and Medical Research Council
Funding Amount
$265,500.00
Summary
The sulfotransferase family of enzymes serve an important role in the metabolism of drugs and foreign chemicals. They also metabolise a range of chemicals that are normally present in the body such as hormones and substances that are involved in brain function (neurotransmitters). Observations from clinical studies suggest that differences in sulfotransferases activities may be a causal factor in the incidence of certain types of cancer and neurodegenerative diseases. Recent advances in understa ....The sulfotransferase family of enzymes serve an important role in the metabolism of drugs and foreign chemicals. They also metabolise a range of chemicals that are normally present in the body such as hormones and substances that are involved in brain function (neurotransmitters). Observations from clinical studies suggest that differences in sulfotransferases activities may be a causal factor in the incidence of certain types of cancer and neurodegenerative diseases. Recent advances in understanding the molecular biology of these enzymes have shown us that multiple forms of sulfotransferase existed within the body. In this area my laboratory has been at the forefront of the cloning and characterisation of these enzymes. Indeed, we were the first laboratory to clone the major human sulfotransferase (SULT1A3) responsible for the metabolism of brain neurotransmitters. We have also used new technology to determine the shape of this important enzyme. At the time of writing my laboratory has characterised a total seven human sulfotransferases but unlike SULT1A3, our knowledge of the functional significance of the other six sulfotransferase is poorly understood. Further, our knowledge of what regulates the amount of sulfotransferase in different tissues is practically nonexistent. The thrust of this project is to extend our studies on the physiological function of these enzymes and also through the use of molecular biology techniques understand what controls the level of their expression in different human tissues. This knowledge will provide a basis for understanding the role of sulfotransferases play in drug and chemical metabolism. It will also aid our understanding of their role in hormone and neurotransmitter metabolism and help determine whether they are involved in such diseases as cancer and neurodegenerative diseases.Read moreRead less