Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Migrating Cells: Folds in the cell membrane supply material for necessary blebs

23.11.2017

In order to be able to move, some cells form protrusions in the form of blebs. How do these blebs form? Researchers at the Cells-in-Motion Cluster of Excellence have discovered that folds in the cell membrane play a decisive role. The study has been published in the journal “Developmental Cell”.

When an organism develops, large numbers of cells migrate from place to place in order to form tissue and organs in the right spots. In order to be able to move, some cells form protrusions in the form of blebs, which point out the direction in which they migrate. These protrusions look like balloons – but, in contrast to the rubber of a balloon, the outer layer of a cell, the cell membrane, cannot expand very much without breaking.


Primordial germ cell of an 18-hours old zebrafish embryo. Right: In order to be able to move, the cell forms a protrusion in the form of a bleb pointing out the direction in which it migrates.

Copyright: Goudarzi et al./Dev. Cell


Left: Folds in the cell membrane (green). Centre: During bleb formation, the folds unfold outwards. Right: During bleb retraction, the folds retract inside the cell. (red: Actin, grey: cell nucleus)

Copyright: Dev. Cell/N. Knubel M.

How do the protrusions form then?

Investigating the migration of primordial germ cells in zebrafish embryos, researchers at the Cells-in-Motion Cluster of Excellence at the University of Münster have discovered that certain folds in the membrane allow the cells to produce blebs. These folds are located inside the cell and they then unfold outwards during bleb formation.

“We were able to show for the first time that these structures play a decisive role in the formation of the blebs,” says cell biologist Prof. Erez Raz, a group leader at the Cells-in-Motion Cluster of Excellence. This knowledge may also be useful for understanding the migration of other types of cells – for example, of certain cancer cells, which move in a similar way. The study has been published in the current issue of the journal “Developmental Cell”.

The detailed story:

Different types of cells migrate in different ways. Some cells develop protrusions in the form of blebs, in the direction of migration, which they use to move. These blebs are formed when pressure in the cytoplasm pushes the cell membrane outwards. In their study, the researchers examined this cell shape deformation in primordial germ cells that migrate within developing zebrafish embryos.

Primordial germ cells migrate in the embryo from the place they are formed towards the region in the embryo where they then give rise to sperm and egg cells within the testis or the ovary. Primordial germ cells can change their shape and extend blebs within a few seconds. “We wanted to find out how the cells can change their shape so rapidly, and what is the source for the membrane ‘material’ required for their formation,” says cell biologist Mohammad Goudarzi, the lead author of the study.

The researchers took a close look at the cell membrane, and identified folds, which are located inside the cell. For the first time, they determined the role of these folds and their dynamic behaviour in a living organism. First, the researchers marked the cell membrane with a fluorescent protein in order to observe it under the microscope. Before the cell formed a bleb, folds could be clearly seen in the membrane. Once a bleb had formed, however, these structures could not be observed anymore – which led the researchers to assume that the folds unfolded and provide membrane material for bleb inflation.

To study the dynamics of the unfolding process, the researchers additionally marked the membrane folds with certain proteins which tend to bind to curved membranes. The researchers were able to observe that those marker proteins were enriched on the front of the migrating cell, the position where the blebs formed. Moreover, inhibiting membrane unfolding resulted in inhibition of bleb formation and migration.

In addition, the researchers discovered that a component of the cell skeleton, the actin protein, was localized to the regions where the folds formed. Actin polymerization is regulated by the protein Cdc42 such that inhibiting its activity reduces the accumulation of actin. Using a confocal microscope, they were able to observe in the living organism that if there was less Cdc42 present, fewer folds were formed. As a result, fewer blebs were formed, the cells’ motility was reduced and, as a result, they no longer reached their target. “In this way, we were able to show that the formation of folds in the cell membrane is regulated by Cdc42 and that the folds are necessary for the formation of blebs and for the cell’s motility,” says Mohammad Goudarzi.

“Our latest findings relating to the question of how cells move could be of general interest – both in the context of physiological processes and also in diseases,” says Erez Raz, because not only primordial germ cells, but also other types of cell form blebs when they migrate: certain cancer cells, for example, when they invade healthy tissues. Protrusions are also formed on the cell’s surface during cell division or when cells die. In the future, the new findings could be tested in other cells and organisms, making them more general and potentially relevant for possible medical applications.

The study received funding from the Cells-in-Motion Cluster of Excellence at the University of Münster, from the Interdisciplinary Centre for Clinical Research (IZKF) at Münster University, as well as from the European Research Council and the German Research Foundation (DFG).

Original publication:

Goudarzi M, Tarbashevich K, Mildner K, Begemann I, Garcia J, Paksa A, M Reichman-Fried M, Mahabaleshwar H, Blaser H, Hartwig J, Zeuschner D, Galic M, Bagnat M, Betz T, Raz E. Bleb expansion in migrating cells depends on supply of membrane from cell surface invaginations. Dev Cell 2017, DOI 10.1016/j.devcel.2017.10.030. Abstract

Media contact:

Svenja Ronge
Media Relations Manager
Tel.: +49 251 83-49310
svenja.ronge@uni-muenster.de

Weitere Informationen:

https://www.uni-muenster.de/Cells-in-Motion/people/all/raz-e.php Prof. Erez Raz/Cells-in-Motion Cluster of Excellence
http://www.cell.com/developmental-cell/fulltext/S1534-5807(17)30874-2 Abstract of the original publication

Svenja Ronge | idw - Informationsdienst Wissenschaft

More articles from Life Sciences:

nachricht Single-stranded DNA and RNA origami go live
15.12.2017 | Wyss Institute for Biologically Inspired Engineering at Harvard

nachricht New antbird species discovered in Peru by LSU ornithologists
15.12.2017 | Louisiana State University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>