Featured Research

from universities, journals, and other organizations

How An Enzyme Tells Stem Cells Which Way To Divide

Date:
May 21, 2009
Source:
University of Oregon
Summary:
Driving Miranda, a protein in fruit flies crucial to switch a stem cell's fate, is not as complex as biologists thought, according to biochemists. They've found that one enzyme stands alone and acts as a traffic cop that directs which roads daughter cells will take.

aPKC is shown in green at the top half of a fruit fly neuroblast. Miranda, in blue, has been driven away to the opposite side. Upon division, the top half will remain a stem cell, while the bottom will become a differentiated cell.
Credit: Courtesy of Kenneth Prehoda

Driving Miranda, a protein in fruit flies crucial to switch a stem cell's fate, is not as complex as biologists thought, according to University of Oregon biochemists. They've found that one enzyme (aPKC) stands alone and acts as a traffic cop that directs which roads daughter cells will take.

Related Articles


"Wherever aPKC is at on a cell's cortex or membrane, Miranda isn't," says Kenneth E. Prehoda, a professor in the chemistry department and member of the UO's Institute of Molecular Biology. When a stem cell duplicates into daughter cells, the side, or cortical domain, containing aPKC (atypical protein kinase C) continues as a stem cell, while the other domain with Miranda becomes a differentiated cell such as a neuron that forms the central nervous system.

Prehoda and co-author Scott X. Atwood, who studied in Prehoda's lab and recently earned his doctorate, describe how the mechanism works in the May 12 issue of the journal Current Biology.

Instead of a complex cascade of protein deactivation steps that many biologists have theorized, Prehoda said, aPKC strips phosphate off an energy-transfer nucleotide known as ATP and then attaches it to Miranda. This process forces Miranda away from aPKC and helps determine the fates of subsequent daughter cells.

"This process is pretty simple," he said, when viewed from a biochemical perspective. "What happens is that Miranda gets phosphorylated by aPKC, turning it into an inactivated substrate and pushing it into another location in the cell."

Much of the paper in Current Biology is devoted to why the more complex scenarios are not accurate. "There have been a lot of ideas on how this works, and most seemed to be really complicated and difficult to explain. We have found it's a much simpler mechanism," Prehoda said, adding that the mechanism likely is similar in many other types of cells, not just stem cells.

"It's a basic-research question. How does this polarity occur? In order to develop stem cell-specific therapeutics based on a rational methodology you have to understand the mechanism," he said.

If Miranda is improperly isolated into other regions by aPKC, the stem cell divides symmetrically, with both daughter cells adopting the same fate, In turn, Prehoda said, these cells can become tumorous as they continue to rapidly divide without proper polarization.

The National Institutes of Health supported the research through a Developmental Biology Training Grant to Atwood and a research grant to Prehoda.


Story Source:

The above story is based on materials provided by University of Oregon. Note: Materials may be edited for content and length.


Journal Reference:

  1. Scott X. Atwood, Kenneth E. Prehoda. aPKC Phosphorylates Miranda to Polarize Fate Determinants during Neuroblast Asymmetric Cell Division. Current Biology, 2009; 19 (9): 723 DOI: 10.1016/j.cub.2009.03.056

Cite This Page:

University of Oregon. "How An Enzyme Tells Stem Cells Which Way To Divide." ScienceDaily. ScienceDaily, 21 May 2009. <www.sciencedaily.com/releases/2009/05/090514102102.htm>.
University of Oregon. (2009, May 21). How An Enzyme Tells Stem Cells Which Way To Divide. ScienceDaily. Retrieved November 28, 2014 from www.sciencedaily.com/releases/2009/05/090514102102.htm
University of Oregon. "How An Enzyme Tells Stem Cells Which Way To Divide." ScienceDaily. www.sciencedaily.com/releases/2009/05/090514102102.htm (accessed November 28, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Friday, November 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Rural India's Low-Cost Sanitary Pad Revolution

Rural India's Low-Cost Sanitary Pad Revolution

AFP (Nov. 28, 2014) — One man hopes his invention -– a machine that produces cheap sanitary pads –- will help empower Indian women. Duration: 01:51 Video provided by AFP
Powered by NewsLook.com
Research on Bats Could Help Develop Drugs Against Ebola

Research on Bats Could Help Develop Drugs Against Ebola

AFP (Nov. 28, 2014) — In Africa's only biosafety level 4 laboratory, scientists have been carrying out experiments on bats to understand how virus like Ebola are being transmitted, and how some of them resist to it. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
WHO Says Male Ebola Survivors Should Abstain From Sex

WHO Says Male Ebola Survivors Should Abstain From Sex

Newsy (Nov. 28, 2014) — WHO cites four studies that say Ebola can still be detected in semen up to 82 days after the onset of symptoms. Video provided by Newsy
Powered by NewsLook.com
Ebola Leaves Orphans Alone in Sierra Leone

Ebola Leaves Orphans Alone in Sierra Leone

AFP (Nov. 27, 2014) — The Ebola epidemic sweeping Sierra Leone is having a profound effect on the country's children, many of whom have been left without any family members to support them. Duration: 01:02 Video provided by AFP
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

 

Health & Medicine

Mind & Brain

Living & Well

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