Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Protein involved in cell division now found key to cell growth

21.11.2003


A research team at The University of Texas M. D. Anderson Cancer Center has found that a single protein known as ARF helps coordinate both growth and division within a cell -- the functions that are often perturbed in cancer development.



Many proteins have been found in cancer research that are associated with either errant cell division or with uncontrolled growth, but ARF is the first "master molecule" that seems to be involved in both crucial aspects of the cell cycle, say the researchers, who published their discovery in the November issue of the journal, Molecular Cell.

The work helps explain why so many human cancers -- more than 40 percent -- are found to have altered ARF proteins, says the study’s lead author, Yanping Zhang, Ph.D., assistant professor in the Department of Molecular and Cellular Oncology.


The picture of molecular cell processes now painted by the investigators also suggests that drugs might be developed that could mimic normal ARF function, he says.

"In cancer, cells need to grow first, and then divide, and we have found the first protein that can, in a coordinated fashion, put the brakes on both of these steps," says Zhang. "This protein, or those associated with it, might offer some new therapeutic strategies to investigate."

ARF and the proteins it has power over are major players in cancer development, say the investigators. ARF is the second most frequently altered protein in cancer development, and it helps manage the tumor suppressor protein p53, which is the most common protein defect associated with cancer. That was already known. Now, this study shows that ARF also controls a protein known as B23, which is found in abnormally high levels in almost every tumor cell -- but, before this work, no one knew both proteins interacted.

In order for a cell to grow, it must produce new proteins. To do that, small round bodies within the cell known as ribosomes develop, based on instructions from the cell’s DNA genetic code, which then guide production of proteins. Putting together ribosome "protein factories" from RNA (decoded DNA) and other molecules is one of the major activities of a cell; without ribosomes, protein production would shut down.

Ribosomes are made up of RNA (decoded DNA) and proteins, and Zhang and colleagues found that ARF can help limit the production of ribosomes, and hinder growth. It does this by "degrading" or inhibiting the B23 protein, which helps trigger mature formation of the ribosome factory. Without B23, ribosomes cannot form, proteins aren’t produced, and a cell cannot grow, says Zhang. Normal cells do need some amount of B23, but cells that are constantly growing, as cancer cells do, contain high levels of B23, he says.

At this point, researchers do not know whether high levels of B23 imply that ARF proteins are mutated, unable to limit production of ribosomes, or if there is just too little ARF protein to degrade high levels of B23 protein.

"B23 has been found to be highly over-expressed in many tumors, such as in breast and ovarian cancers, but no one knows why that is or how to control it," says Zhang. "Now we at least know that ARF can control B23, and it may mean a drug that mimics ARF could help inhibit the protein and help control cell growth."

Cells that grow often divide, and ARF has a known function in regulating that aspect of the cell cycle, says Zhang. ARF works in conjunction with the p53 protein, a tumor suppressor that blocks the cell cycle if the cell starts to grow erratically. Abnormally high levels of molecules that signal this kind of growth activates ARF, which in turn allows p53 to accumulate in the cell to halt that growth.

"The importance of ARF is that it can control the two related activities, growth and division, that are key to cancer development," says Zhang. "ARF can inhibit the cell cycle by activating p53 and can also inhibit cell growth by inhibiting B23."


The study is funded by the National Institutes of Health and by M. D. Anderson Cancer Center. Zhang’s co-authors include, from M. D. Anderson’s Department of Molecular and Cellular Pathology: Koji Itahana, Ph.D.; Krishna Bhat, Ph.D.; Aiwen Jin, Yoko Itahana; and from the Department of Molecular Pathology: David Hawke; and Ryuji Kobayashi, Ph.D.

Heather Russell | EurekAlert!

More articles from Life Sciences:

nachricht Topologische Quantenchemie
21.07.2017 | Max-Planck-Institut für Chemische Physik fester Stoffe

nachricht Topological Quantum Chemistry
21.07.2017 | Max-Planck-Institut für Chemische Physik fester Stoffe

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Manipulating Electron Spins Without Loss of Information

Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.

For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...

Im Focus: The proton precisely weighted

What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.

To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...

Im Focus: On the way to a biological alternative

A bacterial enzyme enables reactions that open up alternatives to key industrial chemical processes

The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....

Im Focus: The 1 trillion tonne iceberg

Larsen C Ice Shelf rift finally breaks through

A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...

Im Focus: Laser-cooled ions contribute to better understanding of friction

Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision

Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Closing the Sustainability Circle: Protection of Food with Biobased Materials

21.07.2017 | Event News

»We are bringing Additive Manufacturing to SMEs«

19.07.2017 | Event News

The technology with a feel for feelings

12.07.2017 | Event News

 
Latest News

NASA looks to solar eclipse to help understand Earth's energy system

21.07.2017 | Earth Sciences

Stanford researchers develop a new type of soft, growing robot

21.07.2017 | Power and Electrical Engineering

Vortex photons from electrons in circular motion

21.07.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>