Featured Research

from universities, journals, and other organizations

How Molecular Muscles Help Cells Divide

Date:
December 18, 2007
Source:
Yale University
Summary:
Time-lapse videos and computer simulations provide the first concrete molecular explanation of how a cell flexes tiny muscle-like structures to pinch itself into two daughter cells at the end of each cell division, according to a report in Science Express.

Time-lapse videos and computer simulations provide the first concrete molecular explanation of how a cell flexes tiny muscle-like structures to pinch itself into two daughter cells at the end of each cell division, according to a report in Science Express.

Related Articles


Cell biologists at Yale and physicists at Columbia teamed up to model and then observe the way a cell assembles the "contractile ring," the short-lived force-producing structure that physically divides cells and is always located precisely between the two daughter cell nuclei.

"This contractile ring is thought to operate like an old-fashioned purse string," said senior author Thomas D. Pollard, Sterling Professor and Chair of the Department of Molecular, Cellular & Developmental Biology at Yale. "It constricts the cell membrane into a cleavage furrow that eventually pinches the cell in two."

Living cells divide into two daughter cells to reproduce themselves. In one-celled organisms like yeast, each cell division yields a new creature. In humans and other multicellular species, cell division creates an adult from an embryo. In fully developed adults, it provides necessary replacements for cells that are continuously dying in the course of natural wear and tear.

Scientists have long studied aspects of how cells actually make this division -- the structure of the cellular machinery, how it assembles and how the machine works. Since the 1970s, it has been known that the contractile ring is made up of muscle-like actin and myosin -- contractile proteins that are involved a process in some ways similar to the muscle contraction used to move arms or legs. However, there was no plausible mechanism to explain how it worked.

"We found that fission yeast cells assemble their contractile ring using a 'search, capture, pull and release' mechanism," said Pollard. "This is important because it shows for the first time how the contractile machinery assembles and how all the pieces get to the right place to get the job done."

Time-lapse imaging and computer modeling demonstrated that cells undergoing mitosis set up small clusters of proteins, or nodes, on the inside of the cell membrane around the equator of the cell. Proteins in these nodes begin to put out a small number of filaments composed of the protein actin. The filaments grow in random directions until they encounter another node, where myosin motors in the contacted node pull on the actin filament, bringing the two nodes together.

However, the researchers found that each connection is broken in about 20 seconds. Releasing the connections and initiating subsequent rounds of "search and capture" appears essential to the assembly process, say the scientists. The assembly involves many episodes of attractions between pairs of nodes proceeding in parallel. Eventually the nodes form into a condensed contractile ring around the equator, ready to pinch the mother into two daughters at a later stage.

"A novel and important aspect of this work was that we used computer simulations at every step to test what is feasible physically and to guide our experiments," said author Ben O'Shaughnessy, professor of chemical engineering at Columbia. "The simulations show that cells use reaction rates that are nearly ideal to make this mechanism work on the time scale of the events in the cells."

"Future work will involve testing the concepts learned from fission yeast in other cells to learn if the mechanism is universal," said Pollard. "Since other cells, including human cells, depend on similar proteins for cytokinesis [cell division], it is entirely possible that they use the same strategy."

Other authors on the paper were Dimitrios Vavylonis at Columbia, Yale and Lehigh University; Jian-Qui Wu and Steven Hao at Yale. The work was supported by research grants from the National Institutes of Health.

Citation: Science Express: (December 13, 2007).


Story Source:

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


Cite This Page:

Yale University. "How Molecular Muscles Help Cells Divide." ScienceDaily. ScienceDaily, 18 December 2007. <www.sciencedaily.com/releases/2007/12/071214145000.htm>.
Yale University. (2007, December 18). How Molecular Muscles Help Cells Divide. ScienceDaily. Retrieved December 22, 2014 from www.sciencedaily.com/releases/2007/12/071214145000.htm
Yale University. "How Molecular Muscles Help Cells Divide." ScienceDaily. www.sciencedaily.com/releases/2007/12/071214145000.htm (accessed December 22, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Monday, December 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Earthworms Provide Cancer-Fighting Bacteria

Earthworms Provide Cancer-Fighting Bacteria

Reuters - Innovations Video Online (Dec. 21, 2014) Polish scientists isolate bacteria from earthworm intestines which they say may be used in antibiotics and cancer treatments. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Existing Chemical Compounds Could Revive Failing Antibiotics, Says Danish Scientist

Existing Chemical Compounds Could Revive Failing Antibiotics, Says Danish Scientist

Reuters - Innovations Video Online (Dec. 21, 2014) A team of scientists led by Danish chemist Jorn Christensen says they have isolated two chemical compounds within an existing antipsychotic medication that could be used to help a range of failing antibiotics work against killer bacterial infections, such as Tuberculosis. Jim Drury went to meet him. Video provided by Reuters
Powered by NewsLook.com
Researchers Test Colombian Village With High Alzheimer's Rates

Researchers Test Colombian Village With High Alzheimer's Rates

AFP (Dec. 19, 2014) In Yarumal, a village in N. Colombia, Alzheimer's has ravaged a disproportionately large number of families. A genetic "curse" that may pave the way for research on how to treat the disease that claims a new victim every four seconds. Duration: 02:42 Video provided by AFP
Powered by NewsLook.com
Monarch Butterflies Descend Upon Mexican Forest During Annual Migration

Monarch Butterflies Descend Upon Mexican Forest During Annual Migration

Reuters - Light News Video Online (Dec. 19, 2014) Millions of monarch butterflies begin to descend onto Mexico as part of their annual migration south. Rough Cut (no reporter narration) Video provided by Reuters
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


Plants & Animals

Earth & Climate

Fossils & Ruins

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