Featured Research

from universities, journals, and other organizations

Biophysics: Order in chaos

Date:
May 2, 2012
Source:
The Agency for Science, Technology and Research (A*STAR)
Summary:
Scientists have built a model to illustrate the process of skeletal muscle contraction. A combination of random protein movements and the elasticity inside muscles helps to maintain a steady force during skeletal muscle contraction.

Bin Chen of the A*STAR Institute of High Performance Computing and Huajian Gao at Brown University, US, have built a model to illustrate the process of skeletal muscle contraction. A combination of random protein movements and the elasticity inside muscles helps to maintain a steady force during skeletal muscle contraction.

The process of skeletal muscle contraction is based around protein filaments sliding inside sarcomeres -- the structural units of muscle fiber. Inside each sarcomere is a set of filament motors, which appear in different densities in different areas. Scientists previously thought that the motor force would change according to the filament load in the muscle, but recent studies have shown that the motor force actually maintains a constant level during the muscle contraction. Despite such breakthroughs, however, it remains unclear exactly how this constant force is maintained in an otherwise chaotic system.

Bin Chen of the A*STAR Institute of High Performance Computing and Huajian Gao at Brown University, US, have now built a model to illustrate the process of skeletal muscle contraction and show how a constant force can be sustained by the protein motors.

The two key proteins in muscle contraction are actin and myosin. Myosin drives the system, forming a thick filament made up of numerous motors which 'grab' onto, bind to and slide past the thinner actin filaments during contraction. This 'grabbing' and sliding motion has been shown to be fairly chaotic in nature, with attachment and release happening at random. When the weight of an object exerts a load on the filaments -- for example, when you try to lift something up -- the muscles must contract, requiring the protein motors to generate a force opposite to the load.

Chen and Gao have created a new skeletal muscle fiber model to demonstrate how contraction forces work. "Our model is designed for the sarcomere," Chen explains. "We consider the thin filament as an elastic rod under a filament force, which is driven by multiple stochastic myosin motors that convert the chemical energy of adenosine-5'-triphosphate (ATP) hydrolysis into stored elastic energy and then function like swinging arms."

The results show that the unique way in which the myosin motors randomly attach and release from actin, coupled with the elastic properties of the motors, generate a consistent force across the whole sarcomere. When there is a higher filament load, more myosin motors are attached to the actin, but the overall motor force remains constant.

"This regulation mechanism may exist in various biological processes and dramatically induces order within a chaotic system," explains Chen. "Our modeling framework can also be further adapted to study the behaviors of other actomyosin complex structures, which is part of our plan for future work in this area."


Story Source:

The above story is based on materials provided by The Agency for Science, Technology and Research (A*STAR). Note: Materials may be edited for content and length.


Journal Reference:

  1. Bin Chen, Huajian Gao. Motor Force Homeostasis in Skeletal Muscle Contraction. Biophysical Journal, 2011; 101 (2): 396 DOI: 10.1016/j.bpj.2011.05.061

Cite This Page:

The Agency for Science, Technology and Research (A*STAR). "Biophysics: Order in chaos." ScienceDaily. ScienceDaily, 2 May 2012. <www.sciencedaily.com/releases/2012/05/120502091613.htm>.
The Agency for Science, Technology and Research (A*STAR). (2012, May 2). Biophysics: Order in chaos. ScienceDaily. Retrieved August 1, 2014 from www.sciencedaily.com/releases/2012/05/120502091613.htm
The Agency for Science, Technology and Research (A*STAR). "Biophysics: Order in chaos." ScienceDaily. www.sciencedaily.com/releases/2012/05/120502091613.htm (accessed August 1, 2014).

Share This




More Health & Medicine News

Friday, August 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

House Republicans Vote to Sue Obama Over Healthcare Law

House Republicans Vote to Sue Obama Over Healthcare Law

Reuters - US Online Video (July 31, 2014) The Republican-led House of Representatives votes to sue President Obama, accusing him of overstepping his executive authority in making changes to the Affordable Care Act. Mana Rabiee reports. Video provided by Reuters
Powered by NewsLook.com
Despite Health Questions, E-Cigs Are Beneficial: Study

Despite Health Questions, E-Cigs Are Beneficial: Study

Newsy (July 31, 2014) Citing 81 previous studies, new research out of London suggests the benefits of smoking e-cigarettes instead of regular ones outweighs the risks. Video provided by Newsy
Powered by NewsLook.com
Dangerous Bacteria Kills One in Florida

Dangerous Bacteria Kills One in Florida

AP (July 31, 2014) Sarasota County, Florida health officials have issued a warning against eating raw oysters and exposing open wounds to coastal and inland waters after a dangerous bacteria killed one person and made another sick. (July 31) Video provided by AP
Powered by NewsLook.com
Health Insurers' Profits Slide

Health Insurers' Profits Slide

Reuters - Business Video Online (July 30, 2014) Obamacare-related costs were said to be behind the profit plunge at Wellpoint and Humana, but Wellpoint sees the new exchanges boosting its earnings for the full year. Fred Katayama reports. 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:
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