Featured Research

from universities, journals, and other organizations

New player is critical to unleashing T cells against disease

Date:
June 23, 2013
Source:
La Jolla Institute for Allergy and Immunology
Summary:
A major study provides new revelations about the intricate pathways involved in turning on T cells, the body’s most important disease-fighting cells. A certain type of protein, called septins, play an essential role in T cell activation.

A major study from researchers at the La Jolla Institute for Allergy and Immunology provides new revelations about the intricate pathways involved in turning on T cells, the body's most important disease-fighting cells, and was published today in the scientific journal Nature.

The La Jolla Institute team is the first to prove that a certain type of protein, called septins, play a critical role in activating a calcium channel on the surface of the T cell. The channel is the portal through which calcium enters T cells from the blood stream, an action essential for the T cell's survival, activation, and ability to fight disease.

Patrick Hogan and Anjana Rao, Ph.D.s, are senior authors on the paper and Sonia Sharma and Ariel Quintana, Ph.D.s, are co-first authors. Drs. Sharma, Rao and Hogan are former researchers at Harvard Medical School with high-level genetics expertise who joined the La Jolla Institute in 2010. Dr. Quintana conducted advanced microscopy that was a major aspect of the study.

Dr. Hogan describes the discovery as another important step in understanding the overall functioning of T cells -- knowledge from which new, more precisely targeted drugs to treat diseases ranging from cancer to viral infections can emerge. "It's like working on an engine, you have to know what all the parts are doing to repair it," he says. "We want to understand the basic machinery inside a T cell. This will enable us to target the specific pressure points to turn up a T cell response against a tumor or virus or to turn it down in the case of autoimmune diseases."

The findings were published in a Nature paper entitled "An siRNA screen for NFAT activation identifies septins as coordinators of store-operated Ca2+ entry."

"We have found that the septin protein is a very strong regulator of the calcium response, which is essential for activating immune cells," says Dr. Sharma, who was recently appointed to a faculty position, and now leads her own independent laboratory at the La Jolla Institute, in addition to serving as scientific director of the newly established RNAi screening center.

Dr. Hogan says the discovery took the research team by surprise. "We knew septins existed in the cellular plasma (surface) membrane, but we didn't know they had anything to do with calcium signaling," he says. Septins are known to build scaffolding to provide structural support during cell division.

This finding builds on Dr. Rao and Dr. Hogan's groundbreaking discovery in 2006 showing that the protein ORAI1 forms the pore of the calcium channel. The channel's entryway had been one of the most sought after mysteries in biomedical science because it is the gateway to T cell functioning and, consequently, to better understanding how the body uses these cells to fight disease.

To the research team's surprise, the septins were forming a ring around the calcium channel. "We aren't sure why, but we theorize that the septins are rearranging the cellular membrane's structure to "corral" the key proteins STIM and ORAI1, and maybe other factors needed for the calcium channel to operate," says Dr. Hogan.

Dr. Sharma adds that, "essentially we believe the septins are choreographing the interaction of these two proteins that are important in instigating the immune response." Without the septins' involvement, T cell activation does not occur.

In the study, the researchers devised a simple visual readout of activity in a main pathway responsible for activation of T cells -- the same pathway that is targeted by the immunosuppressive drug cyclosporin A that is used clinically -- and looked for impairment of the activity when individual genes were, in effect, deleted. After sorting through the roughly 20,000 human genes, they turned up 887 gene "hits," says Dr. Hogan.

With further experiments, they should be able to classify those hits into genes that affect the calcium channel itself and genes that act later in the pathway. "We are hopeful that one or more of these genes can be used as a clinical target for new drugs to treat transplant rejection and immune diseases, some of the same indications now treated with cyclosporine A," adds Dr. Hogan. He believes that a medication aimed at an early step of calcium entry through the ORAI channel could be more effective and have fewer side effects than cyclosporin A, which targets a later step in the pathway and can cause complications such as kidney disease.


Story Source:

The above story is based on materials provided by La Jolla Institute for Allergy and Immunology. Note: Materials may be edited for content and length.


Journal Reference:

  1. Sonia Sharma, Ariel Quintana, Gregory M. Findlay, Marcel Mettlen, Beate Baust, et al. An siRNA screen for NFAT activation identifies septins as coordinators of store-operated Ca2 entry. Nature, 2013 DOI: 10.1038/nature12229

Cite This Page:

La Jolla Institute for Allergy and Immunology. "New player is critical to unleashing T cells against disease." ScienceDaily. ScienceDaily, 23 June 2013. <www.sciencedaily.com/releases/2013/06/130623144925.htm>.
La Jolla Institute for Allergy and Immunology. (2013, June 23). New player is critical to unleashing T cells against disease. ScienceDaily. Retrieved August 20, 2014 from www.sciencedaily.com/releases/2013/06/130623144925.htm
La Jolla Institute for Allergy and Immunology. "New player is critical to unleashing T cells against disease." ScienceDaily. www.sciencedaily.com/releases/2013/06/130623144925.htm (accessed August 20, 2014).

Share This




More Health & Medicine News

Wednesday, August 20, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Possible Ebola Patient in Isolation at California Hospital

Possible Ebola Patient in Isolation at California Hospital

Reuters - US Online Video (Aug. 20, 2014) — A patient who may have been exposed to the Ebola virus is in isolation at the Kaiser Permanente South Sacramento Medical Center. Linda So reports. Video provided by Reuters
Powered by NewsLook.com
Raw: World's Oldest Man Lives in Japan

Raw: World's Oldest Man Lives in Japan

AP (Aug. 20, 2014) — A 111-year-old Japanese was certified as the world's oldest man by Guinness World Records on Wednesday. Sakari Momoi, a native of Fukushima in northern Japan, was given a certificate at a hospital in Tokyo. (Aug. 20) Video provided by AP
Powered by NewsLook.com
Do More Wedding Guests Make A Happier Marriage?

Do More Wedding Guests Make A Happier Marriage?

Newsy (Aug. 20, 2014) — A new study found couples who had at least 150 guests at their weddings were more likely to report being happy in their marriages. Video provided by Newsy
Powered by NewsLook.com
Ebola-Hit Sierra Leone's Freetown a City on Edge

Ebola-Hit Sierra Leone's Freetown a City on Edge

AFP (Aug. 19, 2014) — Residents of Sierra Leone's capital voice their fears as the Ebola virus sweeps through west Africa. Duration: 00:56 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins