Navigation Links
Innate immunity
Date:6/4/2013

In animal cells, DNA molecules are normally restricted to the cell nucleus and the mitochondria. When DNA appears outside these organelles in the so-called cytosol - it most probably originates from a bacterial pathogen or a DNA virus. This is why cytosolic DNA triggers a strong response by the innate immune system. However, various types of insult can also lead to the release into the cytosol of the cell's own DNA. In this case, the resulting immune response may precipitate an autoimmune disease.

The innate immune system is the body's first line of defense against invasive pathogens. It reacts to intruders by inducing the production of interferon proteins that alert the adaptive arm of the immune system. However, the protein that recognizes DNA which is "out of place" in the cytosol resisted identification until a short time ago. "It was only recently discovered that the enzyme cGAS serves as the sensor," says Professor Karl-Peter Hopfner of LMU's Genzentrum. Hopfner and his colleagues have now determined the three-dimensional structure of this DNA detector.

Cytosolic DNA activates enzyme

Indeed, as they report in the journal Nature, the LMU researchers not only delineated the structure of the cGAS molecule itself, they also elucidated the conformation of the complex formed when it binds to DNA. Careful analysis of both structures, together with further functional studies carried out in collaboration with Professor Veit Hornung of Bonn University, enabled the scientists to work out how cGAS recognizes, and is activated by, cytosolic DNA. Binding of the DNA alters the structure of cGAS, enabling the enzyme to catalyze the synthesis of a cyclic dinucleotide. This molecule then activates a transmembrane protein, which in turn stimulates the production of interferon. "In a second study, published simultaneously in Nature, we also determined the structure of the dinucleotide, and show that it represents a previously unknown form of this class of signaling molecule," Hornung adds.

To their surprise, the researchers also found that cGAS is structurally and mechanistically related to an antiviral enzyme that triggers an immune response upon detection of foreign RNA in the cytosol. "With this finding we have the first evidence for a mechanistic and evolutionary link between DNA- and RNA-induced immune reactions," Hopfner comments.

The new results are also very interesting from a clinical standpoint, as a better understanding of the interferon response could have implications for therapy, in two respects. On the one hand, targeted stimulation of interferon production could enhance immunotherapies directed against tumors. Conversely, the ability to attenuate misdirected immune responses against the body's own antigens could lead to better treatments for autoimmune conditions.


'/>"/>

Contact: Kathrin Bilgeri
kathrin.bilgeri@lmu.de
49-892-180-6938
Ludwig-Maximilians-Universitt Mnchen
Source:Eurekalert

Related biology news :

1. Innate immune system protein provides a new target in war against bacterial infections
2. UTSW researchers identify new enzyme that acts as innate immunity sensor
3. Innate immunity system of sheep and goat herds against viral infections clarified
4. Flu immunity is affected by how many viruses actually cause the infection
5. Behind closed doors: Researchers show how probiotics boost plant immunity
6. Circuitry of cells involved in immunity, autoimmune diseases exposed
7. Pitt team finds immunity protein that ramps up inflammation, and agents that can block it
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:5/23/2017)... GENOA, Italy , May 23, 2017  Hunova, the first robotic ... and trunk, has been officially launched in Genoa, Italy ... Europe and the USA . The ... launched on the market by the IIT spin-off Movendo Technology thanks to ... view the Multimedia News Release, please click: ...
(Date:4/24/2017)... , April 24, 2017 ... and partner with  Identity Strategy Partners, LLP (IdSP) ... "With or without President Trump,s March 6, 2017 ... Terrorist Entry , refugee vetting can be instilled with ... resettlement. (Right now, all refugee applications are suspended ...
(Date:4/13/2017)... , April 13, 2017 UBM,s Advanced ... will feature emerging and evolving technology through ... Innovation Summits will run alongside the expo portion of ... sessions, panels and demonstrations focused on trending topics within ... advanced design and manufacturing event will take place June ...
Breaking Biology News(10 mins):
(Date:6/22/2017)... ... June 22, 2017 , ... RURO, Inc., a leading ... 6.5, a content-packed update to the Limfinity® framework. , LimitLIS® and other RURO ... diverse base of customers among labs and other businesses. Limfinity® 6.5 adds new ...
(Date:6/20/2017)... Pa. , June 20, 2017  Kibow Biotech ... pleased to announce the issuance of a new patent ... or hyperuricemia by the U.S. Patent and Trademark Office ... a winner of the Buzz of Bio award in ... is akin to developing non-drug approaches to chronic disease. ...
(Date:6/19/2017)... ... June 19, 2017 , ... ... clinical development reported today that it is launching two new additions of its ... be demonstrating new capabilities at the DIA 2017 Annual Meeting in Chicago, IL, ...
(Date:6/16/2017)... ... June 16, 2017 , ... CTNext , Connecticut’s go-to resource ... held at The LOFT at Chelsea Piers in Stamford. , Nine finalists, all of ... of judges for an opportunity to secure $10,000 awards to help support business growth. ...
Breaking Biology Technology: