Scientists Discover How Protein Crucial For Motion Is Synthesized At The Right Place In The Cell

Scientists Discover How Protein Crucial For Motion Is Synthesized At The Right Place In The Cell: "'The ZBP1 bound to actin's messenger RNA acts like a lock to prevent it from being translated into protein before reaching its destination,' explains Dr. Singer. 'On arriving at the cell periphery, the messenger RNA/ZBP1 complex encounters an enzyme, the protein kinase Src, which is active only in that part of the cell. Src adds a phosphate group to ZBP1 close to where it binds to messenger RNA, and this phosphorylation reaction detaches ZBP1 from the actin messenger RNA--unlocking the messenger RNA so it can now be translated into the actin protein that makes cell movement possible.'"

p53 Dark Side Of A Key Anti-tumor Guardian

New Clues To The Dark Side Of A Key Anti-tumor Guardian: "Past work has shown that in animal models, hyperactivation of the p53 protein is beneficial in terms of bestowing extra protection against tumor formation, but at the same time it has a significant negative effect: a shortening of lifespan, accompanied by hallmarks of accelerated aging, including osteoporosis, decreased stress resistance, and organ atrophy.
Although researchers over recent years have established a foothold in understanding how p53 protects against cancer, the mechanisms by which it might contribute to aging and lifespan are not well studied. In work reported this week, researchers studying p53 function in fruit flies show new evidence that despite the protective role of p53 as a guardian against tumor formation, normal levels of p53 activity--at least in some cell types--may indeed contribute to aging and decreased lifespan."

Scientists Map One Of Biology's Critical Light-sensing Structures

Scientists Map One Of Biology's Critical Light-sensing Structures: "In the Nov. 17, 2005 issue of the journal Nature: a team of scientists from the University of Wisconsin-Madison report that they have obtained the crystal structure of a phytochrome from a bacterium, the first such light-gathering structure depicted for all of biology. The structure of the bacterial phytochrome, according to the report, suggests its architecture first arose a billion or so years ago in a common ancestor and is shared among not only bacteria, but also by plants and fungi."

Protein Behavior May Lead To Better Treatment Of Neurodegenerative Diseases

Protein Behavior May Lead To Better Treatment Of Neurodegenerative Diseases: "Using a technique called fluorescence resonance energy transfer or FRET, the team measured distances between two specific points on the protein. Special fluorescent chemical groups - a donor and an acceptor - are attached to those points. If the donor and acceptor are within 8-10 nanometers apart, FRET occurs. The lifetime of the donor drops significantly when FRET occurs.

In this series of experiments, the group used FRET and ALEX (alternating laser excitation) to probe donors and acceptors on folded and unfolded protein sub-populations. They were able to separate the fluorescence lifetime of the unfolded proteins from the folded proteins.

The structure in the energy landscape is what encourages it to fold or not to fold,” he said. “You want to see what protein is doing in an unfolded state and why it folds. Then you can understand why the folding sometimes goes wrong.”

Laurence said protein folding gone awry can provide some keys to as to why certain people are prone to Alzheimer’s or other neurodegenerative diseases. In addition, understanding how and why protein folds can help scientists design proteins to perform specific tasks.

The research appears in the Proceedings of the National Academy of Sciences online edition for the week of Nov. 14-18. It will appear in print in the Nov. 29 edition."

Ku86 Genetic Switch Involved In Cells' DNA topoisomerase I Response To Radiation Therapy

Researchers Discover Genetic Switch Involved In Cells' Response To Radiation Therapy: "The investigation focused on an enzyme called DNA topoisomerase I, which is responsible for cutting single DNA strands so that the DNA molecule can rotate and unwind during transcription and replication. Camptothecin stops DNA topoisomerase I during the unwinding process, ultimately killing the cell."

Important DNA Repair Mechanism Linked To Premature Aging Yields

Important DNA Repair Mechanism Linked To Premature Aging Yields: "The protein CSB, which in a mutated form causes one kind of Cockayne Syndrome, was known to recognize stalled RNAPII; CSB was presumed to be involved in initiating transcription-coupled repair, but by what means was unknown. In addition, there were hints for an important but unknown role for the protein XPG in transcription-coupled repair. In both humans and mice, when gene mutations produce a severely truncated form of XPG, the result is profound Cockayne Syndrome and very early death.
Through an ingenious series of biochemical experiments, Cooper and her colleagues discovered evidence that XPG and CSB must work together in recognizing stalled RNAPII. The researchers learned that these proteins spot stalled RNAPII whether or not there is damage to DNA � suggesting that a hitch in the transcription process, not necessarily involving damage to the DNA itself, is the cause of subsequent problems."

platelet activating factor: PAF

Scientists Show How Thinking Can Harm Brain Cells: "In laboratory studies, brain cells and slices were exposed to platelet-activating factor, or PAF, a compound that promotes inflammation and plays many roles in the brain. It can be produced by neurons and takes part in the working of synapses, including activity associated with learning and remembering. It also is produced by immune cells during inflammation. The amount of PAF in the brain increases dramatically in HIV-1-associated dementia and other neurodegenerative diseases."

Dynamic Personalities Of Proteins Reveal Key Traits: New Window Opens On Structure And Function Of Enzymes

Dynamic Personalities Of Proteins Reveal Key Traits: New Window Opens On Structure And Function Of Enzymes: "A Brandeis University study published in Nature this week advances fundamental understanding of the dynamic personalities of proteins and proposes that these enzymes are much more mobile, or plastic, than previously thought. The research, based on nuclear magnetic resonance (NMR) experiments, may shed new light on how to improve rational drug design through docking to dynamic targets.

For the first time ever, the study linked both the low-energy as well as the much rarer high-energy state of enzymes to their function, said lead author Brandeis biophysicist Dorothee Kern.

The research involved NMR studies of the enzyme cyclophilin A, a highly conserved protein found in all organisms from yeast to the human body, and which is involved in HIV replication in humans. "