Navigation Links
How molecular muscles help cells divide

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
Yale University  

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:
Related Image:
How molecular muscles help cells divide
(Date:4/11/2017)... , April 11, 2017 NXT-ID, Inc. ... technology company, announces the appointment of independent Directors Mr. ... to its Board of Directors, furthering the company,s corporate governance ... Gino ... we look forward to their guidance and benefiting from their ...
(Date:4/4/2017)... 2017   EyeLock LLC , a leader of ... States Patent and Trademark Office (USPTO) has issued U.S. ... of an iris image with a face image acquired ... company,s 45 th issued patent. ... given the multi-modal biometric capabilities that have recently come ...
(Date:3/29/2017)... -- higi, the health IT company that operates the largest ... , today announced a Series B investment from BlueCross ... new investment and acquisition accelerates higi,s strategy to create ... health activities through the collection and workflow integration of ... and secures data today on behalf of over 36 ...
Breaking Biology News(10 mins):
(Date:10/12/2017)... ... 12, 2017 , ... DuPont Pioneer and recently formed CasZyme, ... into a multiyear collaboration to identify and characterize novel CRISPR-Cas nucleases. The goal ... editing across all applications. , Under the terms of the agreement, Pioneer will ...
(Date:10/12/2017)... ... October 12, 2017 , ... ... platform specifically designed for life science researchers to analyze and interpret datasets, ... Franklin, who made a major contribution to the discovery of the double-helix ...
(Date:10/11/2017)... ... , ... ComplianceOnline’s Medical Device Summit is back for its 4th year. The ... Francisco, CA. The Summit brings together current and former FDA office bearers, regulators, industry ... officials from around the world to address key issues in device compliance, quality and ...
(Date:10/11/2017)... , ... October 11, 2017 , ... Disappearing forests and ... lives of over 5.5 million people each year. Especially those living in larger cities ... Treepex - based in one of the most pollution-affected countries globally - decided to ...
Breaking Biology Technology: