Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Sweetening neurotransmitter receptors and other neuronal proteins

28.10.2016

Researchers discover a “sugar-code” for neuronal membrane proteins.

To rapidly carry information throughout the body, neurons form intricate networks by sending long protrusions to physically contact other neurons, sometimes meters away from where their main body (hence called the cell body) is located. These tree-like protrusions are either called axons if they are used to send information or dendrites if they receive information from other neurons.


Many neuronal proteins have atypical glycosylation profiles consistent with the virtual absence of an important organelle, the Golgi apparatus, in neuronal processes

Max Planck Institute for Brain Research

Axons and dendrites contact one another at specialized communication structures called synapses where the axon stimulates the dendrite by releasing small chemical compounds called neurotransmitters, that bind to specialized proteins called neurotransmitter receptors which are expressed at the surface of dendrites, and trigger electric signals that travel through the rest of the cell when they are activated.

Sugar molecules, so-called glycans, are one of the components of these receptor proteins, but were not well studied in neurons until now. In a recent paper, Cyril Hanus and colleagues in the Schuman Lab at the Frankfurt Max Planck Institute for Brain Research showed that many neuronal proteins have atypical glycosylation profiles consistent with the virtual absence of an important organelle, the Golgi apparatus, in neuronal processes. These atypical sugar molecules change how the receptors respond to neurotransmitters.

In all cells, surface proteins are made inside the cell in a compartment called the endoplasmic reticulum. During this process, one or several complex sugar molecules are usually added to newly made proteins. These sugar molecules are then modified as the proteins leave the endoplasmic reticulum and pass through another compartment called the Golgi apparatus on the way to the cell surface. The precise number and structure of the sugar molecules attached to the protein define its glycosylation profile.

To adapt their response to synaptic stimulation, for example during learning, neurons control how many receptors are expressed at the cell surface, in particular by producing more of these receptors. These new receptors can be made in the main cell body but, to speed up the process during memory formation, also locally in dendrites, close to synapses where they are needed. However, while the endoplasmic reticulum is found all over the neuron, including in the dendrites, the Golgi apparatus is generally only present in the main cell body. It was not known how surface proteins are made in the dendrites or how the proteins’ glycosylation profiles are altered in the absence of a Golgi apparatus.

Hanus et al. used microscopy and advanced biochemical techniques to study the glycosylation profiles of surface proteins in rat neurons. The experiments revealed that immature glycosylation profiles are found on hundreds of different proteins that have been transported to the cell surface. This includes many neurotransmitter receptors but also numerous other key surface proteins. Next, Hanus et al. selectively blocked the modification of sugar molecules on proteins in the Golgi apparatus. This showed that dendrites are able to form and work properly even if surface proteins have primarily immature glycosylation profiles. Finally, the authors showed that these immature glycosylation profiles change the way neurotransmitter receptors react to stimulation by neurotransmitters, showing that the glycosylation profile of surface proteins impact their function.

Cyril Hanus: “These new results show that neurons can produce surface proteins in a way that is different from other cells, and in doing so control important aspects of the function of these proteins, a process that may, in the long run, be exploited to design new medicines tailored to neuronal proteins.”

Publication: Hanus, C., Geptin, H., Tushev, G., Garg, S., Alvarez-Castelao, B., Sambandan, S., Kochen, L., Hafner, A.S., Langer, J.D., Schuman, E.M. (2016). Unconventional secretory processing diversifies neuronal ion channel properties. eLife 5: e20609 (https://elifesciences.org/content/5/e20609/article-info)

Weitere Informationen:

http://tinyurl.com/jxl8vxc

Dr. Arjan Vink | Max-Planck-Institut für Hirnforschung

More articles from Life Sciences:

nachricht Barium ruthenate: A high-yield, easy-to-handle perovskite catalyst for the oxidation of sulfides
16.07.2018 | Tokyo Institute of Technology

nachricht The secret sulfate code that lets the bad Tau in
16.07.2018 | American Society for Biochemistry and Molecular Biology

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 evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Subaru Telescope helps pinpoint origin of ultra-high energy neutrino

16.07.2018 | Physics and Astronomy

Barium ruthenate: A high-yield, easy-to-handle perovskite catalyst for the oxidation of sulfides

16.07.2018 | Life Sciences

New research calculates capacity of North American forests to sequester carbon

16.07.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>