Featured Research

from universities, journals, and other organizations

Tightly Controlled Protein Destruction Drives The Cell Cycle

Date:
September 21, 1998
Source:
University Of Pennsylvania Medical Center
Summary:
Ubiquitin -- as the name suggests -- is found in cells throughout the body. In fact, this 76-amino-acid-long protein appears in nearly identical form in many other species, even some quite distant from humans on the phylogenic tree. Yeast ubiquitin, for example, differs from the human protein by only three of its amino-acid building blocks. What, then, makes ubiquitin so vital that it has been so strongly conserved during evolution?

Ubiquitin -- as the name suggests -- is found in cells throughout the body. In fact, this 76-amino-acid-long protein appears in nearly identical form in many other species, even some quite distant from humans on the phylogenic tree. Yeast ubiquitin, for example, differs from the human protein by only three of its amino-acid building blocks. What, then, makes ubiquitin so vital that it has been so strongly conserved during evolution? Research from the laboratory of Sandra L. Holloway, PhD, an assistant professor of genetics at Penn and assistant investigator with the Howard Hughes Medical Institute, is beginning to answer that question.

Holloway's studies have shown that ubiquitin plays a crucial role in precisely coordinating the transition between two steps in mitosis, a step in the cycle of cell division that underlies all growth, renewal, and repair.

After the cell has duplicated the DNA in its chromosomes in the metaphase step of mitosis, but before the chromosomes have separated in the anaphase step, a group of 13 proteins known as the anaphase-promoting complex, or APC, identifies and tags pivotal metaphase proteins with ubiquitin.

Then, in a process referred to as ubiquitin-mediated proteolysis, a large tubular enzyme called a proteosome recognizes the protein-ubiquitin pairing and destroys the protein while releasing the ubiquitin to be used again. The destruction of the metaphase proteins frees the cell to continue to the anaphase step in the cell cycle.

Currently, experiments in Holloway's laboratory are aimed at understanding precisely which APC proteins see and bind to specific proteins to facilitate the metaphase-anaphase transition. Her team recently discovered that an APC component called CDC23 binds to cyclin, a protein known to be essential in earlier steps of mitosis, leading to its destruction. According to Holloway, disruptions in the ubiquitin system have been linked to a number of human diseases, including colorectal and other cancers, Parkinson's disease, Alzheimer's disease, cystic fibrosis, Down's syndrome, and less common disorders such as Liddle's syndrome and Angelman syndrome. A better understanding of ubiquitin-mediated proteolysis, therefore, could form the basis for the development of new drugs to treat these and other diseases.


Story Source:

The above story is based on materials provided by University Of Pennsylvania Medical Center. Note: Materials may be edited for content and length.


Cite This Page:

University Of Pennsylvania Medical Center. "Tightly Controlled Protein Destruction Drives The Cell Cycle." ScienceDaily. ScienceDaily, 21 September 1998. <www.sciencedaily.com/releases/1998/09/980919123150.htm>.
University Of Pennsylvania Medical Center. (1998, September 21). Tightly Controlled Protein Destruction Drives The Cell Cycle. ScienceDaily. Retrieved August 30, 2014 from www.sciencedaily.com/releases/1998/09/980919123150.htm
University Of Pennsylvania Medical Center. "Tightly Controlled Protein Destruction Drives The Cell Cycle." ScienceDaily. www.sciencedaily.com/releases/1998/09/980919123150.htm (accessed August 30, 2014).

Share This




More Health & Medicine News

Saturday, August 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

3 Things To Know About The Ebola Outbreak's Progression

3 Things To Know About The Ebola Outbreak's Progression

Newsy (Aug. 29, 2014) Here are three things you need to know about the deadly Ebola outbreak's progression this week. Video provided by Newsy
Powered by NewsLook.com
Killer Amoeba Found in Louisiana Water System

Killer Amoeba Found in Louisiana Water System

AP (Aug. 28, 2014) State health officials say testing has confirmed the presence of a killer amoeba in a water system serving three St. John the Baptist Parish towns. (Aug. 28) Video provided by AP
Powered by NewsLook.com
Who Could Be Burnt by WHO's E-Cigs Move?

Who Could Be Burnt by WHO's E-Cigs Move?

Reuters - Business Video Online (Aug. 28, 2014) The World Health Organisation has called for the regulation of electronic cigarettes as both tobacco and medical products. Ciara Lee looks at the impact of the move on the tobacco industry. Video provided by Reuters
Powered by NewsLook.com
CDC Director On Ebola Outbreak: 'It's Worse Than I Feared'

CDC Director On Ebola Outbreak: 'It's Worse Than I Feared'

Newsy (Aug. 28, 2014) CDC director Tom Frieden says the Ebola outbreak is even worse than he feared. But he also said there's still hope to contain it. 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:
from the past week

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