Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How our cellular antennas are formed

22.01.2019

UNIGE researchers have succeeded in reconstructing in vitro the frame of a cell's cilium; an additional step to understand the pathologies associated with ciliary dysfunctions, from brain malformations to kidney or liver diseases

Most of our cells contain an immobile primary cilium, an antenna used to transfer information from the surrounding environment. Some cells also have many mobile cilia that are used to generate movement.


This is a model of the human cilium frame (left), whose cross-section shows the nine microtubule doublets (bottom right); the dotted frame surrounds a doublet. Top right: atomic model of a doublet formed in vitro.

Credit: © UNIGE

The 'skeleton' of the cilium consists of microtubule doublets, which are 'pairs' of proteins essential for their formation and function. Defects in the assembly or functioning of the cilia can cause various pathologies called ciliopathies.

Scientists from the University of Geneva (UNIGE), Switzerland, have developed an in vitro system capable of forming microtubule doublets, and have uncovered the mechanism and dynamics of their assembly.

Their study, published in the journal Science, reveals the crucial role of tubulin, a real building block, in preventing the uncontrolled formation of ciliary structures. This method will make it possible to discover and exploit possible differences between the cilia of human cells and those of pathogens, allowing for the development of new treatments.

The cells sense many light, mechanochemical or biological signals thanks to an immobile primary cilium. Many mobile cilia, called flagella, may also be present on some cells.

They are able to produce a movement, such as the moving of an embryo from the fallopian tube to the uterus, the evacuation of mucus into the airways, or the swimming of the spermatozoids.

Defects in the assembly or function of cilia can lead to ciliopathies, a group of diseases including brain malformations, retinal or fertility disorders, kidney or liver diseases, recurrent respiratory infections and skeletal anomalies.

Mounting a scaffold in a test tube

At the base of the cilium are two centrioles, organelles formed by microtubules, which are components of the cytoskeleton. The centriole is the starting point for the construction of the cilium, which will consist of nine doublets of microtubules.

"The doublet is a structure essential for the formation and functions of cilia, but its assembly was unknown until now", explains Paul Guichard, Professor at the Department of Cell Biology of the UNIGE Faculty of Science.

The group of Paul Guichard and Virginie Hamel, co-head of the laboratory, has developed an in vitro system capable of forming doublets of microtubules. The researchers also used advanced microscopy and modeling techniques, in collaboration with researchers from the Institut Curie d'Orsay in France and the Prague Institute of Biotechnology in the Czech Republic.

At first, nine microtubules are formed from the centriole through the assembly of "bricks" of tubulin. A doublet then forms on the surface of each microtubule.

"We observed that the formation of the doublet is regulated by the tubulin itself, as the removal of one of its ends causes the formation of the doublet at this place. This effect probably prevents the uncontrolled formation of the microtubule doublet elsewhere than in the cilium, ensuring its optimal functioning", explains Virginie Hamel, co-leader of the study.

By filming this phenomenon using state-of-the-art microscopes, the researchers also showed for the first time that the second microtubule is assembled in two opposite directions by adding tubulin bricks.

Inhibit the movement of parasites

The axis of the cilium or flagellum also serves as a "rail" for the movement of "trains" of molecules from one end of the organelle to the other, propelled by real molecular motors.

These transports are necessary for all the functions of the organelle. "We now intend to discover if there are any differences in the assembly and functioning of cilia or flagella of certain parasites, such as malaria, compared to their human counterparts. Such differences could thus become the target of treatments that would only affect the pathogens", concludes Paul Guichard.

Media Contact

Paul Guichard
Paul.Guichard@unige.ch
41-223-796-750

 @UNIGEnews

http://www.unige.ch 

Paul Guichard | EurekAlert!
Further information:
http://dx.doi.org/10.1126/science.aav2567

More articles from Life Sciences:

nachricht The hidden structure of the periodic system
17.06.2019 | Max-Planck-Institut für Mathematik in den Naturwissenschaften (MPIMIS)

nachricht Tiny probe that senses deep in the lung set to shed light on disease
17.06.2019 | University of Edinburgh

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: The hidden structure of the periodic system

The well-known representation of chemical elements is just one example of how objects can be arranged and classified

The periodic table of elements that most chemistry books depict is only one special case. This tabular overview of the chemical elements, which goes back to...

Im Focus: MPSD team discovers light-induced ferroelectricity in strontium titanate

Light can be used not only to measure materials’ properties, but also to change them. Especially interesting are those cases in which the function of a material can be modified, such as its ability to conduct electricity or to store information in its magnetic state. A team led by Andrea Cavalleri from the Max Planck Institute for the Structure and Dynamics of Matter in Hamburg used terahertz frequency light pulses to transform a non-ferroelectric material into a ferroelectric one.

Ferroelectricity is a state in which the constituent lattice “looks” in one specific direction, forming a macroscopic electrical polarisation. The ability to...

Im Focus: Determining the Earth’s gravity field more accurately than ever before

Researchers at TU Graz calculate the most accurate gravity field determination of the Earth using 1.16 billion satellite measurements. This yields valuable knowledge for climate research.

The Earth’s gravity fluctuates from place to place. Geodesists use this phenomenon to observe geodynamic and climatological processes. Using...

Im Focus: Tube anemone has the largest animal mitochondrial genome ever sequenced

Discovery by Brazilian and US researchers could change the classification of two species, which appear more akin to jellyfish than was thought.

The tube anemone Isarachnanthus nocturnus is only 15 cm long but has the largest mitochondrial genome of any animal sequenced to date, with 80,923 base pairs....

Im Focus: Tiny light box opens new doors into the nanoworld

Researchers at Chalmers University of Technology, Sweden, have discovered a completely new way of capturing, amplifying and linking light to matter at the nanolevel. Using a tiny box, built from stacked atomically thin material, they have succeeded in creating a type of feedback loop in which light and matter become one. The discovery, which was recently published in Nature Nanotechnology, opens up new possibilities in the world of nanophotonics.

Photonics is concerned with various means of using light. Fibre-optic communication is an example of photonics, as is the technology behind photodetectors and...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

SEMANTiCS 2019 brings together industry leaders and data scientists in Karlsruhe

29.04.2019 | Event News

Revered mathematicians and computer scientists converge with 200 young researchers in Heidelberg!

17.04.2019 | Event News

First dust conference in the Central Asian part of the earth’s dust belt

15.04.2019 | Event News

 
Latest News

Novel communications architecture for future ultra-high speed wireless networks

17.06.2019 | Information Technology

Climate Change in West Africa

17.06.2019 | Earth Sciences

Robotic fish to replace animal testing

17.06.2019 | Ecology, The Environment and Conservation

VideoLinks
Science & Research
Overview of more VideoLinks >>>