One of the most amazing engineering achievements in nature is how over 2 meters of genetic material (DNA) can be compacted and squeezed nearly a million times to fit into a human cell. The remarkable structure that achieves this is the chromosome. Fundamental to the survival of a multicellular organism is that the chromosome is stably maintained throughout out the life of an organism. For example, defects in maintaining chromosome stability can lead to aneuploidy (cells with an abnormal number o ....One of the most amazing engineering achievements in nature is how over 2 meters of genetic material (DNA) can be compacted and squeezed nearly a million times to fit into a human cell. The remarkable structure that achieves this is the chromosome. Fundamental to the survival of a multicellular organism is that the chromosome is stably maintained throughout out the life of an organism. For example, defects in maintaining chromosome stability can lead to aneuploidy (cells with an abnormal number of chromosomes), a feature exhibited by many forms of cancer. This packaging of genomic DNA that produces a chromosome is achieved by a complex scheme of folding. At the first level, DNA is first wrapped around a mixture of proteins (called histones) to form a complete unit known as a nucleosome. About 30 million of these building blocks are required in every human cell to compact our DNA. Higher, more complicated levels of organization exist in which a linear array of nucleosomes fold to various extents to form distinct functional and structural domains. Importantly, specialised chromosomal domains, like the telomere and centromere, are assembled that keep the ends of the chromosomes stable and enable a chromosome to copy itself every time our cells divide and grow, respectively. How a chromosome is divided into these different compartments remains a mystery. This investigation will show that a key cellular mechanism that determines how the chromosome is organised into stable domains is by changing the make-up of chromosomal domains through the replacement of histone proteins with specialised forms of histones called variants . These histone variants control the way a linear array of nucleosomes fold into complex three-dimensional structures to perform a specialised function. This fundamental research will provide important new information on how chromosomes become unstable in cancer. It will also enable new strategies, which stabilise the chromosome, to be explored.Read moreRead less
Cells must regulate the flow of ions and water across their membranes in order to survive and function normally. The balance of ions and water is controlled by ion channels - proteins that control the permeability of the cell membrane. Of the ion channels, chloride channels are the most abundant in cells. They are central to the functioning of normal cells as well as playing a key role in many disease states. Our group was the first to identify and characterise a new class of chloride channel wh ....Cells must regulate the flow of ions and water across their membranes in order to survive and function normally. The balance of ions and water is controlled by ion channels - proteins that control the permeability of the cell membrane. Of the ion channels, chloride channels are the most abundant in cells. They are central to the functioning of normal cells as well as playing a key role in many disease states. Our group was the first to identify and characterise a new class of chloride channel which plays a key roles in the regulation of the immune system. These channels are unusual in that they can move between two states: a soluble state and a state that resides in the cell membrane. We have determined the first structures of this class of channel in both the soluble state and what is believed to be the membrane docking state. This has given us the first atomic picture of how this channel protein can alter its structure so as to carry out its function. In this project, we will determine: how the protein completes the transition into the membrane state; the structures of other key members of this class of channel protein; complexes between channel proteins and other cellular proteins; and the structure of the protein in the membrane state. We will also determine how several drugs control the activity of this channel. The results of our work will have specific implications for our channel and will serve as a paradigm other members of this new class of chloride channel. Understanding how this channel functions and how the current drugs control it will lead to the development of a new class of therapeutic agents that will control these channels by preventing the transition from the soluble to the membrane state.Read moreRead less
Structural And Drug Discovery Studies Of Oxidative Stress Regulator, Thioredoxin-interacting Protein
Funder
National Health and Medical Research Council
Funding Amount
$288,210.00
Summary
Toxic oxygen molecules known as Reactive Oxygen Species (ROS) are by-product of normal metabolism. The excess of ROS is damaging and is well known to contribute to ageing process and age-related diseases such as cancer, diabetic complications, immune-system decline, and cardiovascular conditions to name a few. The human body possesses several defense systems that protect us from the excess of ROS maintaining a healthy level of ROS. A down-regulator of one of this systems, a protein called TXNIP, ....Toxic oxygen molecules known as Reactive Oxygen Species (ROS) are by-product of normal metabolism. The excess of ROS is damaging and is well known to contribute to ageing process and age-related diseases such as cancer, diabetic complications, immune-system decline, and cardiovascular conditions to name a few. The human body possesses several defense systems that protect us from the excess of ROS maintaining a healthy level of ROS. A down-regulator of one of this systems, a protein called TXNIP, has been recently discovered. The amount of TXNIP is increased in such conditions as high glucose, a first sign of diabetes, and under ischemia, a shortage of blood supply occurring during heart attack. This weakens the anti-oxidant defense systems and makes the organism more vulnerable to ROS exposure. Our team of researchers embarked on structural and functional studies of TXNIP with the purpose to identify small molecules that can interfere with the undesirable action of TXNIP. These molecules might become useful therapeutic agents to counteract weakening organism's ROS defense system caused by TXNIP in many disease conditions such as, cancer, diabetes and cardiac failure.Read moreRead less