Featured Research

from universities, journals, and other organizations

Hybrid-motor helps cells push their way through tissues

Date:
August 8, 2014
Source:
University of Warwick
Summary:
Research has uncovered how two cellular motors, previously thought to compete with each other, can actually work together to help cells squeezing through a crowded mass of cells. The study provides fresh understanding of how cells can combine accurate steering with a brute force mechanism in order to push through our body, essential when cells of our immune defense need to reach sites of inflammation, but detrimental during tumor metastasis or parasitic infection.

Cell blebbing.
Credit: University of Warwick

Research has uncovered how two cellular motors, previously thought to compete with each other, can actually work together to help cells squeezing through a crowded mass of cells.

The study published in PNAS provides fresh understanding of how cells can combine accurate steering with a brute force mechanism in order to push through our body, essential when cells of our immune defense need to reach sites of inflammation, but detrimental during tumor metastasis or parasitic infection. The work was conducted by Dr Till Bretschneider and Dr Richard University of Warwick's Systems Biology Centre and a team at the Medical Research Laboratory of Molecular Biology in Cambridge.

One of the cellular motors causes the cell membrane, the flexible envelope encasing all cells, to bulge out by forming so-called pseudopods. "In this instance, cell locomotion is driven by the localised growth of a dynamic protein scaffold pushing against the cell membrane from the inside," says Dr Tyson, continuing, "Cells employ complex regulation, linked to environmental sensing, to make pseudopods highly accurate steering devices, which are of limited power though."

The second motor entails faster, pressure-driven protrusions in form of cellular blebs. These provide higher force, working like a battering ram to open up gaps for cells to squeeze in-between other tightly connected cells. "Like a muscle, a cell is able to contract itself, increasing its internal pressure and causing the cell membrane to locally tear away from the underlying cytoskeletal scaffold. Pressure then blows it outwards to force aside other cells or to create footholds for traction as a rock climber would," says Dr Tyson. In contrast to pseudopods, blebs appeared to be under less precise control as to where they form on a cells' surface, making the impression of a loose cannon.

Recently Evgeny Zatulovskiy and Rob Kay from Cambridge have shown that Dictyostelium cells, a popular model organism for studying cell locomotion, can employ both motors simultaneously[2], raising the question of how they might interact.

To address this question Richard Tyson and Till Bretschneider from Warwick University developed new computer algorithms capable of tracking large numbers of both blebs and pseudopods in microscopy movies of Dictyostelium cells. In the current study, How blebs and pseudopods cooperate during chemotaxis, they demonstrate that cell shape influences how these motors interact. When slow pseudopods extend they deform the cell membrane creating an inward-curved regions at their base.

A biophysical model shows that the cell membrane, which is under tension, experiences an outward directed force in these regions, facilitating the tearing away of membrane, which precedes the formation of a bleb. "Thus, membrane geometry turns out to be an important, previously overlooked factor coupling both types of protrusions and helping to indirectly orient blebs," says Dr Bretschneider. This mechanism is similar to blistering of an overly thick coat of drying paint where moisture is trapped underneath and expands when the temperature increases.

Like the cell membrane, drying paint is also under tension, which is more easily released on inward curved surfaces, where it preferably causes paint to blister or flake off. An example of an inward curved surface where this applies would be a ceiling coving, as opposed to a plane wall. Cellular pseudopods can actively create inward curved surfaces and consequently direct where blebs form.

"The significance of this work is two-fold," Dr Bretschneider explains, "Firstly, the underlying mechanism is a generic physical one, similar to the example of drying paint. It has been confirmed to exist in different cell types and is independent of a cell's sensory system. Secondly, until now the common picture was that the requirements for forming one type of protrusion or the other are mutual exclusive. The current study shows that both motors can actually work together to make cell motility more effective by providing accurate steering to a high power motor."


Story Source:

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


Journal References:

  1. R. A. Tyson, E. Zatulovskiy, R. R. Kay, T. Bretschneider. How blebs and pseudopods cooperate during chemotaxis. Proceedings of the National Academy of Sciences, 2014; DOI: 10.1073/pnas.1322291111
  2. E. Zatulovskiy, R. Tyson, T. Bretschneider, R. R. Kay. Bleb-driven chemotaxis of Dictyostelium cells. The Journal of Cell Biology, 2014; 204 (6): 1027 DOI: 10.1083/jcb.201306147

Cite This Page:

University of Warwick. "Hybrid-motor helps cells push their way through tissues." ScienceDaily. ScienceDaily, 8 August 2014. <www.sciencedaily.com/releases/2014/08/140808110726.htm>.
University of Warwick. (2014, August 8). Hybrid-motor helps cells push their way through tissues. ScienceDaily. Retrieved September 22, 2014 from www.sciencedaily.com/releases/2014/08/140808110726.htm
University of Warwick. "Hybrid-motor helps cells push their way through tissues." ScienceDaily. www.sciencedaily.com/releases/2014/08/140808110726.htm (accessed September 22, 2014).

Share This



More Plants & Animals News

Monday, September 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Raw: San Diego Zoo Welcomes Cheetah Cubs

Raw: San Diego Zoo Welcomes Cheetah Cubs

AP (Sep. 20, 2014) The San Diego Zoo has welcomed two Cheetah cubs to its Safari Park. The nearly three-week-old female cubs are being hand fed and are receiving around the clock care. (Sept. 20) Video provided by AP
Powered by NewsLook.com
Chocolate Museum Opens in Brussels

Chocolate Museum Opens in Brussels

AFP (Sep. 19, 2014) Considered a "national heritage" in Belgium, chocolate now has a new museum in Brussels. In a former chocolate factory, visitors to the permanent exhibition spaces, workshops and tastings can discover derivatives of the cocoa bean. Duration: 01:00 Video provided by AFP
Powered by NewsLook.com
Could Grief Affect The Immune Systems Of Senior Citizens?

Could Grief Affect The Immune Systems Of Senior Citizens?

Newsy (Sep. 19, 2014) The study found elderly people are much more likely to become susceptible to infection than younger adults going though a similar situation. Video provided by Newsy
Powered by NewsLook.com
Jury Delivers Verdict in Salmonella Trial

Jury Delivers Verdict in Salmonella Trial

AP (Sep. 19, 2014) A federal jury has convicted three people in connection with an outbreak of salmonella poisoning five years ago that sickened hundreds of people and was linked to a number of deaths. (Sept. 19) Video provided by AP
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