Featured Research

from universities, journals, and other organizations

3-D Imaging Of Motor Proteins Provides New Insights To Molecular Mechanics Of Cell Motility, Muscle Contraction

Date:
October 3, 2005
Source:
Burnham Institute
Summary:
Scientists from the Burnham Institute for Medical Research and the University of Vermont have captured the first 3-dimensional (3D) atomic-resolution images of the motor protein myosin V as it "walks" along other proteins, revealing new structural insights that advance the current model of protein motility and muscle contraction. The culmination of four years of work, this collaboration among biochemists and structural biologists was selected as the cover story for the September issue of the scientific journal Molecular Cell.

Dorit Hanein, Ph.D., Associate Professor, Hong-Jun Liu, Ph.D., Postdoctoral Associate, Larnelle Hazelwood, Research Assistant, and Niels Volkmann, Ph.D., Assistant Professor.
Credit: Image courtesy of Burnham Institute

La Jolla, CA (September 29, 2005) -- Scientists from the Burnham Institute for Medical Research and the University of Vermont have captured the first 3-dimensional (3D) atomic-resolution images of the motor protein myosin V as it "walks" along other proteins, revealing new structural insights that advance the current model of protein motility and muscle contraction. The culmination of four years of work, this collaboration among biochemists and structural biologists was selected as the cover story for the September issue of the scientific journal Molecular Cell.

The Burnham team, led by Dorit Hanein, Ph.D., was the first to reveal the 3D representation of myosin V "walking" along actin filament, a key protein involved in motility and muscle contraction. Using electron-cryo microscopy to take 3D snapshots of myosin V and actin interacting, researchers were able to see myosin V moving along the actin substrate in a "natural state." Previous 2D models have been based on staining or other treatment of the myosin that might alter the complex's natural mechanism of action.

Myosins are a large family of motor proteins that interact with actin filaments for motor movement and muscle contraction. Myosin V is the workhorse of the myosin protein family. It exists to ferry a cargo of proteins needed in a specific place at a specific time. Fueled by hydrolysis -- the process of converting the molecule adenosine triphosphate (ATP) into energy -- myosin V travels in one direction using actin as a track to deliver its payload of cell vesicles and organelles. Myosin V is also involved in transporting proteins that signal and communicate with other cells.

Myosin V has a two-chained "tail" that diverges to form two "heads" that bind to specific grooves on actin and walk hand over hand along the track, similar to the way a child moves along the monkey bars in a playground. Myosin V differs from the other myosin family proteins in that it is able to sustain this processive motion, enduring many hydrolysis cycles. The other myosins grab on tightly to actin and release after one hydrolysis cycle.

"This study required a different way of thinking about image analysis. This is the first time we were able to structurally visualize the weak binding states of actin and myosin, not interpolated from crystal structures, and not interpolated from biophysical methods," said Dr. Hanein. "We were able to see structural changes in the myosin lever arm as well as in the actin interface as it propagates through the hydrolysis cycle."

Structural information from previous studies provided information about parts of this process, but until the present collaboration, visualizing Myosin V in its weakly bound state to actin had not been possible. The Hanein group captured snapshots of Myosin V at several points during a hydrolysis cycle. Their use of electron cryo-microscopy made it possible to visualize flexible structural domains, which tether the Myosin V, helping to keep the protein on its actin track through the weak binding phase of the processive movement.

The detailed molecular knowledge of how myosin interacts through the hydrolysis cycle with actin provides an exciting new research template onto which scientists can design new sets of experiments to further refine the myosin-actin binding region and to correlate it with loss or gain of function. The precise characterization of this myosin-actin interface is critical, evident by the way a single amino acid change in myosin leads to familial hypertrophic cardiomyopathy (FHC), an undetectable condition resulting in death by sudden cardiac arrest in otherwise healthy young adults.

Contributors to this work include: Niels Volkmann, Ph.D., assistant professor and first author on this publication, Dorit Hanein, Ph.D., associate professor, Hong-Jun Liu and Larnele Hazelwood from the Burnham Institute for Medical Research; and Kathleen M. Trybus, Ph.D., Susan Lowey, Ph.D., and Elena B. Kremenstova, Ph.D., from the Department of Molecular Physiology and Biophysics at the University of Vermont.

Functional, biochemical assays were conducted by collaborators from the University of Vermont, directed by Kathleen Trybus, Ph.D.

###

This research was supported by grants from the National Institutes of Health.

The Burnham Institute for Medical Research, founded in 1976, is an independent not-for-profit biomedical research institution dedicated to advancing the frontiers of scientific knowledge and providing the foundation for tomorrow's medical therapies. The Institute is home to three major research centers: the Cancer Center, the Del E. Webb Neuroscience and Aging Center, and the Infectious and Inflammatory Disease Center. Since 1981, the Institute's Cancer Center has been a member of the National Cancer Institute's prestigious cancer centers program. Discoveries by Burnham scientists have contributed to the development of new drugs for Alzheimer's Disease, heart disease and several forms of cancer. Today, the Burnham Institute employs over 700, including more than 550 scientists. The majority of the Institute's funding is derived from federal sources, but private philanthropic support is essential to continuing bold and innovative research. For additional information about the Institute and ways to support the research efforts of the Institute, visit: http://www.burnham.org.


Story Source:

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


Cite This Page:

Burnham Institute. "3-D Imaging Of Motor Proteins Provides New Insights To Molecular Mechanics Of Cell Motility, Muscle Contraction." ScienceDaily. ScienceDaily, 3 October 2005. <www.sciencedaily.com/releases/2005/10/051001102026.htm>.
Burnham Institute. (2005, October 3). 3-D Imaging Of Motor Proteins Provides New Insights To Molecular Mechanics Of Cell Motility, Muscle Contraction. ScienceDaily. Retrieved April 24, 2014 from www.sciencedaily.com/releases/2005/10/051001102026.htm
Burnham Institute. "3-D Imaging Of Motor Proteins Provides New Insights To Molecular Mechanics Of Cell Motility, Muscle Contraction." ScienceDaily. www.sciencedaily.com/releases/2005/10/051001102026.htm (accessed April 24, 2014).

Share This



More Matter & Energy News

Thursday, April 24, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Next Stop America for France's TGV?

Next Stop America for France's TGV?

Reuters - Business Video Online (Apr. 24, 2014) General Electric keeps quiet on reports it's in talks to buy French turbine and train maker Alstom. Ivor Bennett reports on what could be an embarrassing rumour for the French government, with business-friendly reforms proving a hard sell. Video provided by Reuters
Powered by NewsLook.com
Raw: Obama Plays Soccer With Japanese Robot

Raw: Obama Plays Soccer With Japanese Robot

AP (Apr. 24, 2014) President Obama briefly played soccer with a robot during his visit to Japan on Thursday. The President has been emphasizing technology along with security concerns during his visit. (April 24) Video provided by AP
Powered by NewsLook.com
Obama Encourages Japanese Student-Scientists

Obama Encourages Japanese Student-Scientists

AP (Apr. 24, 2014) President Obama spoke with student innovators in Japan and urged them to take part in increased opportunities for student exchanges with the US. (April 24) Video provided by AP
Powered by NewsLook.com
UN Joint Mission Starts Removing Landmines in Cyprus

UN Joint Mission Starts Removing Landmines in Cyprus

AFP (Apr. 23, 2014) The UN mission in Cyprus (UNFICYP) led a mine clearance demonstration on Wednesday in the UN-controlled buffer zone where demining operations are being conducted near the Cypriot village of Mammari. Duration: 01:00 Video provided by AFP
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