Enzyme's second messenger contributes to cell overgrowth

Sep 26, 2007

Scientists at the University of California, San Diego (UCSD) School of Medicine have uncovered a novel pathway by which hormones elevated in inflammation, cancer and cell injury act on cells to stimulate their growth.

The research team led by Joan Heller Brown, Ph.D., professor and chair of the department of pharmacology at UCSD, has demonstrated in a mouse model that a newly discovered subtype of the phospholipase C (PLC) family of enzymes, called PLC-epsilon, has the unique ability to activate a second and distinct signaling pathway that cells require for proliferation. The study is currently on line in advance of publication by the Proceedings of the National Academy of Science.

The studies reported in the PNAS demonstrate that “in the cell, hormones that activate small G proteins are highly dependent on PLC-º to generate second messengers,” said Heller Brown. “In addition, and more surprisingly, we discovered that this enzyme is required for cell growth because it serves a second function when activated by hormones.”

Many intracellular signaling proteins work as molecular “switches.” The reception of a signal activates them and causes them to pass the signal through the cell, after which they can be switched off until another signal is received. G proteins are a commonly used form of switch, activated by the binding of guanine nucleotides.

PLC’s normal role is delivering signals from outside the cell to inside the cell by generating “second messengers” that tell cells to contract and secrete. But these signals alone are not enough to cause cells to increase their growth. The first author of the paper, Simona Citro, Ph.D., and colleagues found that PLC-º uniquely activates a second and distinctly different signaling cascade. This second signal catalyzes activation of a Ras family of small G proteins associated with cell growth.

“In combination with the first set of signals, this can lead to cell proliferation and could contribute to inflammation or cancer if left unchecked,” said Citro.

“PLC plays a critical role in physiological processes including heart function, cell secretion and blood pressure control, so one would not normally want to block its activity,” added Heller Brown. The UCSD researchers’ discovery may enable scientists to target this novel PLC isoform or inhibit only its second function, preventing pathological responses while leaving PLC’s critical positive role intact.

Source: University of California - San Diego

Explore further: Premature aging: Scientists identify and correct defects in diseased cells

Related Stories

A nano-transistor assesses your health via sweat

May 15, 2015

Made from state-of-the-art silicon transistors, an ultra-low power sensor enables real-time scanning of the contents of liquids such as perspiration. Compatible with advanced electronics, this technology ...

Mystery methane on Mars: The saga continues

May 15, 2015

Is the Red Planet giving off methane? The question has taunted scientists for nearly 50 years, ever since the Mariner 7 spacecraft detected a whiff of the gas near Mars' south pole. Researchers retracted ...

Exposing breast cancer using nanoscale polymers

May 13, 2015

Photoacoustic imaging is a ground-breaking technique for spotting tumors inside living cells with the help of light-absorbing compounds known as contrast agents. A*STAR researchers have now discovered a way ...

Recommended for you

Why you need one vaccine for measles and many for the flu

18 hours ago

While the influenza virus mutates constantly and requires a yearly shot that offers a certain percentage of protection, old reliable measles needs only a two-dose vaccine during childhood for lifelong immunity. ...

Scientists turn blood into neural cells

18 hours ago

Scientists at McMaster University have discovered how to make adult sensory neurons from human patients simply by having them roll up their sleeve and providing a blood sample.

How our gut changes across the life course

21 hours ago

Scientists and clinicians on the Norwich Research Park have carried out the first detailed study of how our intestinal tract changes as we age, and how this determines our overall health.

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.