Navigation Links
Common bacteria pirate natural mechanism to get inside cells

Bacteria and viruses utilize a natural mechanism to get inside cells and grow, researchers say.

These pathogens gain entry the same way millions of receptors on the cell's surface routinely do after they get activated, says Dr. Yehia Daaka, professor and Distinguished Chair in Oncologic Pathology at the Medical College of Georgia. Dr. Daaka is corresponding author on an article published Jan. 23 by Proceedings of the National Academy of Sciences.

By moving off the cell surface, receptors gain some respite from their activating signals, Dr. Daaka says. Receptors can either stay inside the newly created vesicle and be degraded or resurface to be activated once again.

Bacteria and viruses also want inside cells and out of the direct line of fire of the immune system or treatments such as antibiotics for bacterial infections, Dr. Daaka says. "Some bacteria and viruses bind to receptors on the plasma membrane and use them to go inside, and that is how they start replicating inside the cell," he says.

He and colleagues at Howard Hughes Medical Institute and Duke University Medical Center also have found that the short-lived, ubiquitous gas, nitric oxide, is a primary enabler for receptors and pathogens to make this move.

"When there is a signal, the plasma membrane on the cell surface invaginates ?think of a plasma membrane as a balloon and you poke your finger in it," he says. "The protein, dynamin, comes along and forms a necklace around the neck of that balloon, then chops it off," he says of the process that is ongoing with millions of receptors on the cell surface. "Adding nitric oxide to dynamin changes it from an inactive protein inside the cell to the active protein that mediates the fission of the vesicle inside the cell."

Apparently, bacteria and viruses can increase nitric oxide levels to make this normally protective system work for them as well.

Identifying this role of nitric oxide provides a new targ et for finding better methods to prevent infections, Dr. Daaka says. "In the case of bacteria, hiding inside the cells is dependent on dynamin. What we could do is limit internalization and ensuing infection by controlling dynamin activity through the inhibition of nitric oxide synthases, enzymes that produce nitric oxide."

The new research uses the common bladder infection-producing uropathogenic E. coli as a model to show how nitric oxide unwittingly assists bacterial uptake and survival.

"In bladder cells, E. coli uses this mechanism to get inside the cells and hide from the antibiotic effect and the immune system," says Dr. Daaka. "We think their hiding is mediated through dynamin. This is not only applicable to this particular pathogen but for many more."

Dr. Daaka, who studies receptor signaling, likens receptors to television antennae that control relay of signals from outside the cell to inside by turning on or off. Although there are no known receptors that have the job of triggering a bad result in the body, receptors that are 'on' too much may end up instructing the cell to do bad things, he says. "The hypothesis is that in cancer, for example, the receptors get stuck on 'on'."

Receptor over-stimulation also helps explain why some drugs stop being effective over time. "What that means is there are no more receptors outside the cells to be affected by the drugs," Dr. Daaka says. "This is a self-regulatory mechanism for cells. You don't want your receptors to always be on."

Interestingly, this self-regulatory mechanism seems to work best when a receptor, not a bacteria, is the instigator. Unlike receptors, bacteria and viruses don't degrade if they stay inside the vesicles because fusion with a second vesicle that enables the degredation doesn't happen, says Dr. Daaka, a Georgia Cancer Coalition Distinguished Cancer Scholar.


'"/>

Source:Medical College of Georgia


Related biology news :

1. Its not all genetic: Common epigenetic problem doubles cancer risk in mice
2. Harmful Bacterium Commonly Found in Poultry May Survive Refrigeration and Frozen Storage Combined
3. Men Estimate Mens Risks Of Common Disorders Higher Than Women Do, And Vice Versa
4. Use of Antibiotics for Acne May Increase Risk of Common Illness
5. Common viruses may cause cancer
6. Common alternative treatment for liver disease is found to be ineffective
7. Common molecular signature identified in solid tumors
8. Commonly used antidepressants may also affect human immune system
9. Common practices at petting zoos put visitors at risk
10. Common enzyme is a key player in DNA repair
11. Common molecular signature identified in solid tumors
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:6/22/2016)... On Monday, the Department of Homeland Security (DHS) issued ... the Biometric Exit Program. The Request for Information (RFI), ... that CBP intends to add biometrics to confirm when ... , in order to deter visa overstays, to ... Logo - http://photos.prnewswire.com/prnh/20160622/382209LOGO ...
(Date:6/9/2016)... June 9, 2016  Perkotek an innovation leader in attendance control systems is proud ... work hours, for employers to make sure the right employees are actually signing in, ... ... ... ...
(Date:6/2/2016)... --  The Weather Company , an IBM Business (NYSE: ... in which consumers will be able to interact with IBM ... voice or text and receive relevant information about the product ... have long sought an advertising solution that can create a ... and valuable; and can scale across millions of interactions and ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... June 23, 2016   Boston Biomedical , ... compounds designed to target cancer stemness pathways, announced ... granted Orphan Drug Designation from the U.S. Food ... gastric cancer, including gastroesophageal junction (GEJ) cancer. Napabucasin ... to inhibit cancer stemness pathways by targeting STAT3, ...
(Date:6/23/2016)... , June 23, 2016  The Prostate Cancer Foundation (PCF) ... precise treatments and faster cures for prostate cancer. Members of the Class of ... 15 countries. Read More About the Class of 2016 ... ... ...
(Date:6/23/2016)... , ... June 23, 2016 , ... In a new ... in Denmark detail how a patient who developed lymphedema after being treated for breast ... results could change the paradigm for dealing with this debilitating, frequent side effect of ...
(Date:6/23/2016)... ... 23, 2016 , ... ClinCapture, the only free validated electronic ... showcase its product’s latest features from June 26 to June 30, 2016 for ... Disrupting Clinical Trials in The Cloud during the conference. DIA (Drug Information ...
Breaking Biology Technology: