Researchers decipher the mecanism of membrane fission

Oct 26, 2012

A cell is composed of a nucleus which encloses its genetic information and the cytoplasm which is itself confined by an external membrane separating the cell from the outside world. The impermeability of the membrane and its ability to repair itself protect the cell from its environment. Although this membrane resistance is fundamental to the survival of the cell, the cell also needs to let in particles necessary for its proper functioning. The mechanism by which a small region of the cytoplasmic membrane invaginates to form a bud that will then be sectioned off to let molecules and other particles into the cell is known as endocytosis.

However, this natural process remains elusive due to the remarkable resistance of the . Aurélien Roux, a professor of biochemistry and member of the National Centres of Competence in Research (NCCR) , heads a team that focused on dynamin, a protein involved in endocytosis, to try to understand how an ultra-resistant membrane can nevertheless let external elements enter into the cell.

The power of dynamin

Scientists conducted in vitro experiments using artificial membrane tubules with a radius of 10 to 100 nanometres. They discovered that once dynamin is injected into the tube, it polymerises. In other words, it forms a helix around the tube and compresses it until it breaks. Dynamin produces the energy necessary for this constriction by "consuming" GTP molecules, much like a car consumes gasoline.

Based on these experiments, Professor Roux's team observed that the location of the is very specific and appears at the boundary between the helix and the membrane. "A change in radius that curves the membrane, caused by the polymerisation of dynamin, induces a stress that promotes the fracture," states Sandrine Morlot, researcher at the Department of Biochemistry. "This is new data allowing us to explain the process of fission."

The researchers were also able to measure the time it took to fission the membrane. Its duration depends on the mechanical properties of the membrane, which vary from one cell to another.

"We found that the ability of dynamin to break an ultra-resistant membrane is due to its torque, that is to say, its rotational force, which is vastly superior to that of other proteins," explains Professor Roux. "By decrypting the effect of dynamin on the membrane, we have come to understand the workings of membrane fission, a phenomenon which is certainly natural but remains extremely complex."

Explore further: Compound from soil microbe inhibits biofilm formation

Related Stories

Crystal structure shows how motor protein works

Sep 18, 2011

The crystal structure of the dynamin protein — one of the molecular machines that makes cells work — has been revealed, bringing insights into a class of molecules with a wide influence on health and disease.

Researchers clock the speed of brain signals

Jun 22, 2011

Two studies featuring research from Weill Cornell Medical College have uncovered surprising details about the complex process that leads to the flow of neurotransmitters between brain neurons -- a dance of ...

Recommended for you

Compound from soil microbe inhibits biofilm formation

14 hours ago

Researchers have shown that a known antibiotic and antifungal compound produced by a soil microbe can inhibit another species of microbe from forming biofilms—microbial mats that frequently are medically harmful—without ...

Researcher among best in protein modeling contests

17 hours ago

A Purdue University researcher ranks among the best in the world in bioinformatics competitions to predict protein structure, docking and function, making him a triple threat in the world of protein modeling.

Survey of salmonella species in Staten Island Zoo's snakes

18 hours ago

For humans, Salmonella is always bad news. The bacterial pathogen causes paratyphoid fever, gastroenteritis and typhoid. But for snakes, the bacteria aren't always bad news. Certain species of Salmonella are a natural part ...

A long-standing mystery in membrane traffic solved

Mar 27, 2015

In 2013, James E. Rothman, Randy W. Schekman, and Thomas C. Südhof won the Nobel Prize in Physiology or Medicine for their discoveries of molecular machineries for vesicle trafficking, a major transport ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.