Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A glimpse into the nanoworld of lymphocyte cell membranes

16.09.2015

University of Freiburg researchers have applied super-resolution methods to study the organization of receptors on B lymphocytes

Antigen receptors on B lymphocytes sense foreign molecules, such as pathogens or vaccines, and activate the B cells to produce antibodies that protect humans against many diseases. Prof. Dr. Michael Reth, Scientific Director of BIOSS Centre for Biological Signalling Studies, and his group have applied three different super-resolution methods to study the distribution of the two major classes of antigen receptors on mature B lymphocytes:


Researchers previously assumed that receptors such as the antigen receptors of class Immunoglobulin M (IgM) and Immunoglobulin D (IgD) are freely diffusing and equally distributed molecules on the membrane (image above). However, the new study shows that these antigen receptors are organized in different membrane compartments, also called "protein islands", with diameters of 150-200 nanometers (image below). This finding is another indication that, at nanoscale distance, the proteins on cellular membranes are highly organized. Credit: Research Group Reth

Immunoglobulin M (IgM) and Immunoglobulin D (IgD). It had been previously assumed that all proteins on the membrane, including receptors, are freely diffusing molecules that only become organized upon binding to specific ligands. Reth’s group found out that IgM and IgD receptors are organized in protein islands.

The researchers from the University of Freiburg collaborated with Prof. Dr. Hassan Jumaa from the University of Ulm/Germany and Prof. Dr. Björn F. Lillemeier from the Salk Institute in La Jolla/USA. The imaging analysis was conducted in collaboration with Dr. Olaf Ronneberger’s group, computer scientist at the University of Freiburg.

The team has published their research findings in the journal Science Signaling. The researchers hope that these new insights into the nanoscale organization of antigen receptors will support the design of more efficient vaccines or better treatments for B cell tumors where membrane organization is often altered.

Using two-color direct stochastical optical reconstruction microscopy (dSTORM), the researchers found that IgM and IgD reside on the plasma membrane of resting B cells in separated protein islands of approximately 150 and 240 nanometers (nm), respectively.

This class-specific compartmentalization of the antigen receptors is also detected by transmission electron microscopy (TEM) and Fab-based proximity-ligation assay (Fab-PLA) studies. Upon B cell activation, the IgM and IgD protein islands became smaller and the two classes of receptors are now found in close proximity to each other.

These studies provide direct evidence for the nanoscale compartmentalization of the lymphocyte membrane. Furthermore, they suggest that upon B cell activation, the different IgM and IgD protein islands form nano-synapses which allow the exchange of lipids and proteins. This could explain how the IgM class antigen receptors find contact to Raft-associated lipids and proteins. The association of IgM with these lipids is a well-known hallmark of B cell activation.

Michael Reth is professor of molecular immunology at the Institute of Biology III at the University of Freiburg and speaker of the Cluster of Excellence BIOSS Centre for Biological Signalling Studies. Palash Maity, lead author of the study, is a postdoc at BIOSS and at the Max Planck Institute of Immunobiology and Epigenetics in Freiburg.

Olaf Ronneberger is working at the Institute of Computer Science. Ronneberger and Hassan Jumaa are both members of BIOSS Centre for Biological Signalling Studies. This study is part of the BIOSS nanoscale explorer program (BiNEP), which is a focus topic in the BIOSS-2 research program. In this program, BIOSS is developing methods to better understand the nanoworld of signaling processes, beyond the 250 nm diffraction limit of visible light.

Original publication:
Palash Chandra Maity, Amy Blount, Hassan Jumaa, Olaf Ronneberger, Björn F. Lillemeier and Michael Reth (2015). B cell antigen receptors of the IgM and IgD classes are clustered in different protein islands that are altered during B cell activation. Science Signaling 8, Issue 394. DOI: 10.1126/scisignal.2005887

Contact:
Prof. Dr. Michael Reth
Institute of Biology III and BIOSS Centre for Biological Signalling Studies
University of Freiburg
Phone: +49 (0)761 / 203 - 97663
E-Mail: michael.reth@bioss.uni-freiburg.de

Weitere Informationen:

http://www.pr.uni-freiburg.de/pm/2015/pm.2015-09-16.128-en

Rudolf-Werner Dreier | idw - Informationsdienst Wissenschaft

More articles from Life Sciences:

nachricht Polymers Based on Boron?
18.01.2018 | Julius-Maximilians-Universität Würzburg

nachricht Bioengineered soft microfibers improve T-cell production
18.01.2018 | Columbia University School of Engineering and Applied Science

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

Im Focus: A thermometer for the oceans

Measurement of noble gases in Antarctic ice cores

The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | 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

 
Latest News

Polymers Based on Boron?

18.01.2018 | Life Sciences

Bioengineered soft microfibers improve T-cell production

18.01.2018 | Life Sciences

World’s oldest known oxygen oasis discovered

18.01.2018 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>