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!
Nanoparticles as a Solution against Antibiotic Resistance?
15.12.2017 | Friedrich-Schiller-Universität Jena
Plasmonic biosensors enable development of new easy-to-use health tests
14.12.2017 | Aalto University
DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.
Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...
MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.
Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
15.12.2017 | Power and Electrical Engineering
15.12.2017 | Materials Sciences
15.12.2017 | Life Sciences