Navigation Links
How molecular muscles help cells divide
Date:12/14/2007

New Haven, Conn. 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.

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 OShaughnessy, 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.


'/>"/>

Contact: Janet Rettig Emanuel
janet.emanuel@yale.edu
203-432-2157
Yale University  
Source:Eurekalert

Related biology news :

1. New molecular regulators of hyperthyroidism and goiter
2. Carnegie Mellon scientists investigate initial molecular mechanism that triggers neuronal firing
3. UC health news: molecular pathway may predict chemotherapy effectiveness
4. New molecular clock from LLNL and CDC indicates smallpox evolved earlier than believed
5. Story ideas from Molecular & Cellular Proteomics
6. Lets talk -- new paradigms in the research of the biomolecular composition of water
7. Scientists unveil structure of molecular target of many drugs
8. Potential new therapeutic molecular target to fight cancer
9. NIH selects LIAI for major study on allergy molecular causes and possible treatments
10. Pennsylvania Hospital surgeon receives grant to develop molecular cardiac surgery
11. Leading cause of death in preemies might be controlled by resetting a molecular switch
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
How molecular muscles help cells divide
(Date:3/24/2017)... Research and Markets has announced the addition ... Trends - Industry Forecast to 2025" report to their offering. ... The Global Biometric ... of around 15.1% over the next decade to reach approximately $1,580 ... market estimates and forecasts for all the given segments on global ...
(Date:3/22/2017)... 21, 2017   Neurotechnology , a provider ... today announced the release of the SentiVeillance ... improved facial recognition using up to 10 surveillance, ... computer. The new version uses deep neural-network-based facial ... it utilizes a Graphing Processing Unit (GPU) for ...
(Date:3/20/2017)... , March 20, 2017 At this year,s ... -based biometrics manufacturer DERMALOG. The Chancellor came to the DERMALOG stand ... is this year,s CeBIT partner country. At the largest German biometrics ... in use: fingerprint, face and iris recognition as well as DERMALOG´s multi-biometrics ... ...
Breaking Biology News(10 mins):
(Date:5/19/2017)... ... May 19, 2017 , ... In response to the strong base ... Medical Systems, Inc. announces the release of their Gait Trainer 3 with an Integrated ... a biomedical system to aid in rehabilitating individuals with cerebral palsy, traumatic brain injury, ...
(Date:5/18/2017)... ... 2017 , ... Clinical Supplies Management (“CSM”), a Great Point Partners II (“GPP”) ... CSM has doubled in size over the past six months with the acquisition ... Roger Gasper joins CSM as Chief Financial Officer. Roger has over 25 years ...
(Date:5/18/2017)... ... May 17, 2017 , ... ... process optimization firm for the life sciences and healthcare industries, is honored that ... Traceability for Medical Devices conference in Brussels, Belgium. , Crowley played a crucial ...
(Date:5/18/2017)... , ... May 18, 2017 , ... When James Sherley, was notified earlier this year ... Valuable Brands for the Year 2017 by The Silicon Review , he was not ... good progress increasing Asymmetrex’s value, but this recognition by Silicon Valley was particularly meaningful. ...
Breaking Biology Technology: