Featured Research

from universities, journals, and other organizations

Biochemical cell signals quantified: Data capacity much lower than expected, scientists find

Date:
September 16, 2011
Source:
Emory University
Summary:
Just as cell phones and computers transmit data through electronic networks, the cells of your body send and receive chemical messages through molecular pathways. The term "cell signaling" was coined more than 30 years ago to describe this process. For the first time, scientists have quantified the data capacity of a biochemical signaling pathway and found a surprise -- it's lower than a dial-up modem.

Just as cell phones and computers transmit data through electronic networks, the cells of your body send and receive chemical messages through molecular pathways. The term "cell signaling" was coined more than 30 years ago to describe this process.

Now, for the first time, scientists have quantified the data capacity of a biochemical signaling pathway and found a surprise -- it's way lower than even an old-fashioned, dial-up modem.

"This key biochemical pathway is involved in complex functions but can transmit less than one bit -- the smallest unit of information in computing," says Ilya Nemenman, an associate professor of physics and biology at Emory University. "It's a simple result, but it changes our view of how cells access chemical data."

The journal Science is publishing the discovery by Nemenman and colleagues from Johns Hopkins University, including Andre Levchenko, Raymond Cheong, Alex Rhee and Chiaochun Joanne Wang.

During the 1980s, cell biologists began identifying key signaling pathways such as nuclear factor kappa B (NF-kB), known to control the expression of genes in response to everything from invading pathogens to cancer. But the amount of information carried by chemical messengers along these pathways has remained a mystery.

"Without quantifying the signal, using math and computer analysis to attach a number to how much information is getting transmitted, you have a drastically incomplete picture of what's going on," says Nemenman, a theoretical biophysicist.

He and Levchenko, a biomedical engineer, began discussing the problem back in 2007 after they met at a conference.

Levchenko developed microfluidic and measurement techniques to conduct experiments on bio-chemical signaling of the NF-kB pathway, and measure the transmissions occurring on the pathway in many thousands of cells at one time. Nemenman formulated the theoretical framework to analyze and quantify the results of the experiments.

"It was a shock to learn that the amount of information getting sent through this pathway is less than one bit, or binary digit," Nemenman says. "That's only enough information to make one binary decision, a simple yes or no."

And yet NF-kB is regulating all kinds of complex decisions made by cells, in response to stimuli ranging from stress, free radicals, bacterial and viral pathogens and more. "Our result showed that it would be impossible for cells to make these decisions based just on that pathway because they are not getting enough information," Nemenman says. "It would be like trying to send a movie that requires one megabit per second through an old-style modem that only transmits 28 kilobits per second."

They analyzed the signals of several other biochemical pathways besides NF-kB and got a similar result, suggesting that a data capacity of less than one bit could be common. So if cells are not getting all the information through signaling pathways, where is it coming from?

"We're proposing that cells somehow talk with each other outside of these known pathways," Nemenman says. "A single cell doesn't have enough information to consider all the variables and decide whether to repair some tissue. But when groups of cells talk to each other, and each one adds just a bit of knowledge, they can make a collective decision about what actions to take."

He compares it to a bunch of people at a cocktail party, with cell phones that have weak signals pressed to their ears. Each person is receiving simple messages via their phones that provide a tiny piece to a puzzle that needs to be solved. When the people chatter together and share their individual messages, they are able to collectively arrive at a reliable solution to the puzzle.

A similar phenomenon, called population coding, had been identified for the electrical activity of neural networks, but Nemenman and his colleagues are now applying the idea to bio-chemical pathways.

They hope to build on this research by zeroing in on the role of cell signaling in specific diseases.

In particular, Nemenman wants to analyze and compare the signaling capacities of a cancerous cell versus a normal cell.

"Cancerous cells divide when they shouldn't, which means they are making bad decisions," he says. "I would like to quantify that decision-making process and determine if cancer cells have reduced information transduction capacities, or if they have the same capacities as healthy cells and are simply making wrong decisions."

Nemenman uses a malfunctioning computer as an example. "If you push the 'a' key on your computer and a 'd' always shows up, that means the computer is misprogrammed but the information from your keystroke gets through just fine," he says. "But if you keep pressing the letter 'a' and different, random letters show up, that indicates a problem with the way the information is being transmitted."


Story Source:

The above story is based on materials provided by Emory University. The original article was written by Carol Clark. Note: Materials may be edited for content and length.


Journal Reference:

  1. Raymond Cheong, Alex Rhee, Chiaochun Joanne Wang, Ilya Nemenman, Andre Levchenko. Information Transduction Capacity of Noisy Biochemical Signaling Networks. Science, 2011; DOI: 10.1126/science.1204553

Cite This Page:

Emory University. "Biochemical cell signals quantified: Data capacity much lower than expected, scientists find." ScienceDaily. ScienceDaily, 16 September 2011. <www.sciencedaily.com/releases/2011/09/110915163531.htm>.
Emory University. (2011, September 16). Biochemical cell signals quantified: Data capacity much lower than expected, scientists find. ScienceDaily. Retrieved October 23, 2014 from www.sciencedaily.com/releases/2011/09/110915163531.htm
Emory University. "Biochemical cell signals quantified: Data capacity much lower than expected, scientists find." ScienceDaily. www.sciencedaily.com/releases/2011/09/110915163531.htm (accessed October 23, 2014).

Share This



More Matter & Energy News

Thursday, October 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Chameleon Camouflage to Give Tanks Cloaking Capabilities

Chameleon Camouflage to Give Tanks Cloaking Capabilities

Reuters - Innovations Video Online (Oct. 22, 2014) — Inspired by the way a chameleon changes its colour to disguise itself; scientists in Poland want to replace traditional camouflage paint with thousands of electrochromic plates that will continuously change colour to blend with its surroundings. The first PL-01 concept tank prototype will be tested within a few years, with scientists predicting that a similar technology could even be woven into the fabric of a soldiers' clothing making them virtually invisible to the naked eye. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Jet Sales Lift Boeing Profit 18 Pct.

Jet Sales Lift Boeing Profit 18 Pct.

Reuters - Business Video Online (Oct. 22, 2014) — Strong jet demand has pushed Boeing to raise its profit forecast for the third time, but analysts were disappointed by its small cash flow. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Internet of Things Aims to Smarten Your Life

Internet of Things Aims to Smarten Your Life

AP (Oct. 22, 2014) — As more and more Bluetooth-enabled devices are reaching consumers, developers are busy connecting them together as part of the Internet of Things. (Oct. 22) Video provided by AP
Powered by NewsLook.com
What Is Magic Leap, And Why Is It Worth $500M?

What Is Magic Leap, And Why Is It Worth $500M?

Newsy (Oct. 22, 2014) — Magic Leap isn't publicizing much more than a description of its product, but it’s been enough for Google and others to invest more than $500M. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins