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!
Advanced analysis of brain structure shape may track progression to Alzheimer's disease
26.10.2016 | Massachusetts General Hospital
Indian roadside refuse fires produce toxic rainbow
26.10.2016 | Duke University
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
27.10.2016 | Materials Sciences
27.10.2016 | Physics and Astronomy
27.10.2016 | Life Sciences