Navigation Links
Study Revises Dynamin's Role in Nerve Cell Function

An unexpected finding on how nerve cells signal to one another could rewrite the textbooks on neuroscience, says a collaborative team of researchers at Weill Cornell Medical College and Yale University.

Their study, published as a high-profile research article in the journal Science, suggests that a key cellular enzyme called dynamin 1 is not essential to all synaptic transmission, as experts had previously assumed.

Dynamin has long been a focus of research for its role in packaging chemical signals, called neurotransmitters, into tiny synaptic vesicles within the cell.

The new study finds that the enzyme is not always necessary for this process. Instead, dynamin 1 goes into action only when the synapse enters moments of especially high activity.

'In that sense, dynamin 1 remains crucial, allowing the synapse the freedom to function under all conditions,' explains co-senior author Dr. Timothy Ryan, professor of biochemistry at Weill Cornell Medical College.

The discovery is a potentially important new piece of the puzzle for scientists investigating neurological injury and disease.

'In the long run, what we're trying to achieve here is a kind of biochemical repair manual' for the brain and brain cells,' Dr. Ryan explains. 'So, in the future, if we find out that a particular illness is caused by a flaw in dynamin 1 function or proteins that interact with dynamin 1, we'll have answers on hand to help fix that.'

Dynamin 1 is one of a family of enzymes involved in synaptic vesicle endocytosis a reverse of the process of transmission of cellular signaling chemicals, whereby molecular components of the vesicle are retrieved from the synapse surface and fit back into a new vesicle to be recycled for reuse after the vesicle has discharged its neurotransmitter. One of the steps in this recycling is a biochemical process called fission.

'Early work with the Drosop hila fruit fly established dynamin 1's role in this vesicle recycling process,' Dr. Ryan explains. 'Essentially, the enzyme undergoes a chemical change whereby it physically squeezes off a piece of the old vesicular membrane creating a brand new vesicle poised to take on a new load of neurotransmitter.'

Based on this work in fruit flies, neuroscientists had assumed that dynamin 1 was necessary for the growth and function of all synaptic transmission.

But Dr. Ryan, along with co-senior author Dr. Pietro De Camilli, a Howard Hughes Medical Institute investigator and professor of cell biology at Yale, decided to test that notion.

Dr. De Camilli's laboratory in New Haven had worked hard to develop a unique, genetically engineered mouse without dynamin 1. If the enzyme was essential to all synaptic activity, these mice would die very soon after birth.

But the pups were born, and initially appeared healthy. 'That was the really big surprise here,' Dr. Ryan says. 'Pups lacking dynamin 1 moved and suckled just like normal pups at birth.'

Lab study revealed that synaptic activity in these mice was functioning at a low level enough to keep the mice alive over the short term without dynamin 1.

'The enzyme's function appears to be much more subtle than we had imagined,' Dr. Ryan says. 'It may not be necessary under conditions of low synaptic activity. In those cases, we suspect that other related enzymes, such as dynamin 2 and 3, may shoulder the load and carry out some residual function.'

'But as soon as cells require higher levels of synaptic activity, dynamin 1 becomes absolutely necessary,' he says.

Normal growth and function demand that neurons work at high capacity, so young mice without dynamin 1 eventually did die off, usually within a week or two of birth.

'These findings really change our outlook on dynamin 1, and on synaptic vesicle endocy tosis in general,' Dr. Ryan says. 'It's an exciting new discovery, one that we didn't expect. But all good science is built on surprises.'

This work was funded by the G. Harold and Leila Y. Mathers Charitable Foundation, the U.S. National Institutes of Health, AIRC (Associazione Italiana per la Ricerca sul Cancro), AICR (American Institute for Cancer Research), Telethon (an Italian foundation), FIRB (Fondo per gli investimenti per la ricerca di base) and COFIN/PRIN, the Canadian Institutes of Health Research, the Human Frontiers Science Program, and the Federazione Italiana per la Ricerca sul Cancro.

Co-researchers include lead author Dr. Shawn M. Ferguson, Mitsuko Hiyashi, Chiara Collesi, Dr. Silvia Giovedi, Dr. Andrea Raimondi, Dr. Liang-Wei Gong, Dr. Richard Flavell and Summer Paradise all of the HHMI and Yale University; Dr. Markus Wolfel and Dr. Gero Miesenbock, of Yale University; Dr. Gabor Brasnjo, of Weill Cornell Medical College; and Dr. Pablo Ariel, of Weill Cornell Medical College and The Rockefeller University.


Related medicine news :

1. Tomato Sauce reduces Cancer Risk- Study
2. Study on obesity and heart failure
3. National Lung Study in the process
4. Study casts doubt on keyboard ills
5. Study reveals how stress can make you sick
6. Study reveals how stress can make you sick
7. Study supports vegetable diet
8. Study to look at early surgery to treat epilepsy
9. Its Never Too Late to Stop Smoking,Study Finds
10. New Technique to Study Infants Brain.
11. Groundbreaking Study Gives Hope For Patients With Kidney Cancer
Post Your Comments:

(Date:11/27/2015)... ... November 27, 2015 , ... The men and women on ... organizations in the country. They have overseen financial turnarounds, shown commitment to their ... healthcare industry as a whole through their advocacy and professional efforts. , Becker's ...
(Date:11/27/2015)... ... November 27, 2015 , ... Indosoft Inc., ... the incorporation of Asterisk 11 LTS (Long Term Support) into its Q-Suite 5.10 ... brings Q-Suite 5.10 up-to-date with a version of Asterisk that will receive not ...
(Date:11/26/2015)... and Cambridge, ON (PRWEB) , ... November 26, ... ... the availability of a real-time eReferral system for diagnostic imaging in the Waterloo ... X-rays, mammography, BMD and Nuclear Medicine tests directly from their electronic medical record ...
(Date:11/26/2015)... NE (PRWEB) , ... November 26, 2015 , ... Jobs ... searched by healthcare professionals and offered by healthcare staffing agency Aureus Medical Group ... during the month of October 2015 among those searching for healthcare jobs through the ...
(Date:11/26/2015)... ... November 26, 2015 , ... Pixel Film ... trailer titles with ProTrailer: Vintage. This newly styled ProTrailer pack comes with 30 ... with any font, giving users limitless opportunities to stylize and create designs quickly ...
Breaking Medicine News(10 mins):
(Date:11/26/2015)... 26, 2015 3D bioprinting market ... to a new report by Grand View Research Inc. Rising ... which demands kidney transplantation is expected to boost the market ... for organ transplantation. --> 3D bioprinting market ... to a new report by Grand View Research Inc. Rising ...
(Date:11/26/2015)... , November 26, 2015 ... of the "2016 Future Horizons and ... Abuse Testing Market: Supplier Shares, Country Segment ... to their offering. --> ... "2016 Future Horizons and Growth Strategies ...
(Date:11/26/2015)... , November 26, 2015 ... --> adds "Global Repaglinide ... "Investigation Report on China Repaglinide Market, ... forecasts data and information to its ... . --> ...
Breaking Medicine Technology: