Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Novel regulation of the common tumor suppressor PTEN

15.01.2007
PTEN is one of the most commonly mutated tumor suppressor genes. It is an antagonist for many cellular growth, proliferation and survival processes. When mutated or deleted, it causes cancers of the prostate, breast, colon, and brain.

Researchers led by scientists at Memorial Sloan-Kettering Cancer Center have now identified fundamentally novel regulatory mechanisms of PTEN function. The findings from two related studies are published in the January 12 issue of Cell.

The first is research by Dr. Xuejen Jiang's laboratory at Sloan-Kettering which identified a novel component that regulates PTEN. This protein, NEDD4-1, controls protein stability in cells. Researchers found that NEDD4-1 is a key component in eliminating PTEN from cells by adding a molecular tag, ubiquitin, to PTEN causing degradation in the cellular machinery called proteasome. In a mouse model for prostate cancer, the researchers found that areas with aggressive tumor contained low PTEN levels and high NEDD4-1. They concluded that NEDD4-1 could promote cancer development by down-regulating PTEN.

The second study by Dr. Pier Paolo Pandolfi of Memorial Sloan-Kettering and colleagues found that the ubiquitination of PTEN by NEDD4-1 also regulates another important aspect of PTEN, its cellular localization.

PTEN has been found mostly in the cytoplasm but has been known to also be in cell nuclei. While the cytoplasmic function of PTEN is now quite well understood, its nuclear functions have been elusive. Looking at a family with an inherited PTEN mutation that caused them to have the cancer-susceptibility condition, Cowden Syndrome, researchers found that the patients' colon cancer strikingly lacked nuclear PTEN.

The Pandolfi and Jiang labs showed that the PTEN mutation in these patients prevented the addition of ubiquitin by NEDD4-1, providing a molecular mechanism for the detrimental effect of the mutant PTEN protein. They showed that the single ubiquitin tagging is necessary to import PTEN into the cell nucleus where it is protected from degradation and cancer is initiated.

According to the researchers, the uncovered key role of PTEN degradation provides a new therapeutic strategy. Since ubiquitination has both positive (single tag) and negative (repetitive tagging) effects, a class of drugs, the proteasome inhibitors, that selectively blocks the degrading effects of ubiquitination, should now be studied as possible treatments for cancers with PTEN mutations.

Joanne Nicholas | EurekAlert!
Further information:
http://www.mskcc.org

More articles from Health and Medicine:

nachricht New malaria analysis method reveals disease severity in minutes
14.08.2017 | University of British Columbia

nachricht New type of blood cells work as indicators of autoimmunity
14.08.2017 | Instituto de Medicina Molecular

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

A Map of the Cell’s Power Station

18.08.2017 | Life Sciences

Engineering team images tiny quasicrystals as they form

18.08.2017 | Physics and Astronomy

Researchers printed graphene-like materials with inkjet

18.08.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>