Navigation Links
Virus mimics human protein to hijack cell division machinery
Date:5/8/2008

MADISON - Viruses are masters of deception, duping their host's cells into helping them grow and spread. A new study has found that human cytomegalovirus (HCMV) can mimic a common regulatory protein to hijack normal cell growth machinery, disrupting a cell's primary anti-cancer mechanism.

Writing in the May 9 issue of Science, researchers from the University of Wisconsin-Madison and Harvard Medical School report that a viral protein, called UL97, masquerades as a normal regulatory enzyme to modify a tumor-suppressing protein in human cells. Unlike the normal enzyme, which can be switched on and off by the cell as needed, the viral stand-in lacks an off switch and evades cellular control. The findings represent a previously unknown way that viruses can cause uncontrolled cell growth and division.

Cells normally have tight regulatory mechanisms in place to limit multiplication to appropriate situations, such as replacing worn-out cells or repairing damage. Uncontrolled cell proliferation can lead to cancer and other disorders.

One of the most important cellular control mechanisms works through a protein called the retinoblastoma tumor suppressor protein, which slows cell growth.

"The retinoblastoma pathway is like the brakes on a car. It prevents tumor cells from growing out of control," says Robert Kalejta, an assistant professor in the UW-Madison Institute for Molecular Virology and McArdle Laboratory for Cancer Research, who led the new study. "This pathway is mutated in essentially all human cancers."

Disrupting this pathway is also advantageous for viruses. Unable to reproduce on their own, viruses rely on co-opting their host's cellular machinery, like an occupying army taking over a local factory. They are especially good at overriding or bypassing built-in control mechanisms, Kalejta says.

"Viruses are well known to encode proteins that have similar activities to cellular proteins, but they're just different enough that they're beneficial to the virus," he says. "[UL97] shares the same activities as the cellular protein, but it lacks all of the control mechanisms."

In essence, UL97 disables the brakes and hits the gas. Once a host cell is primed toward growth, HCMV takes over and steals the cell's machinery to reproduce itself.

The virus's bloodhound-like ability to seek out and target the most essential pieces of a cell's machinery makes it a valuable research tool, Kalejta says.

"Viruses are smarter than we are. They know a lot more about cells than we do, because their life depends on it - they're obligate intracellular parasites," he says. "If they attack a part of the cell - a process or a protein - you know it's important for the cell. If the virus pays attention to it, you should too."

Kalejta next hopes to use UL97 to find other proteins that may be important for cell growth. He also sees potential clinical applications down the road. HCMV infection is very common and, though it remains asymptomatic in most people, it has been implicated in some cancers and can cause trouble in people with compromised or suppressed immune systems, such as AIDS patients and transplant recipients. In addition, UL97-like proteins are also found in the other seven human herpes viruses, some of which are directly linked to cancers.

The advantages of the research are two-fold, Kalejta says. "We're studying a virus that causes human disease and might eventually find a way to treat that infection and help patients. At the same time, we're learning about how the cell works, which has implications for patients that don't have infections," he says. "You get two for the price of one."


'/>"/>

Contact: Robert Kalejta
rfkalejta@wisc.edu
608-265-5546
University of Wisconsin-Madison
Source:Eurekalert

Related medicine news :

1. Grapefruit Compound Inhibits Hepatitis C Virus
2. New agent strikes at respiratory syncytial virus replication
3. OPEN LETTER: Medical Journal Calls Upon Barack Obama to Set the Record Straight on AIDS Virus
4. State Legislature Declares April 21 to 25, 2008 West Nile Virus and Mosquito and Vector Control Awareness Week
5. Study provides new understanding of forces behind seasonal flu virus evolution
6. Cedars-Sinai Medical Center opens patient trial of virus that attacks brain cancer cells
7. FDA OKs New Rotavirus Vaccine
8. FDA APPROVES ROTARIX(R) [Rotavirus Vaccine, live, oral], THE FIRST VACCINE LICENSED TO COMPLETE THE ROTAVIRUS IMMUNIZATION SERIES BY FOUR MONTHS OF AGE
9. Governor Rendell Proposes County Grants to Combat West Nile Virus, Protect Public Health
10. Biologists Discover How Dengue Virus Matures
11. Scientists see Norwalk virus Achilles heel
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/29/2016)... (PRWEB) , ... April 29, 2016 , ... On Tuesday, ... hospitals across the Southeast, celebrated the signature of Gov. Nathan Deal on SB 258, ... Geoff Duncan (R - Cumming), offers a 70% tax credit to individuals and corporations ...
(Date:4/29/2016)... ... April 29, 2016 , ... The White House ... their loans, more information about their loan terms and accounts, and more protections ... debt, including federal and private loans, has reached $1.3 trillion, with 43 million ...
(Date:4/29/2016)... ... April 29, 2016 , ... ... that infants born with severe congenital diaphragmatic hernia have better survival rates if ... congenital diaphragmatic hernia (CDH)—a condition where the diaphragm fails to form completely, letting ...
(Date:4/29/2016)... ... April 29, 2016 , ... Mobility Designed is ... pressure on the armpits, the M+D Crutch evenly distributes body weight from the elbow ... and hands when using the crutches than with other crutches. , Co-founders Max and ...
(Date:4/29/2016)... Tarzana, CA (PRWEB) , ... April 29, 2016 , ... Melanoma is the deadliest type ... is to blame for the majority of skin cancer deaths. More than 10,000 people are ... average age at diagnosis is 62, it is the one of the most commonly diagnosed ...
Breaking Medicine News(10 mins):
(Date:4/28/2016)... , April 28, 2016 TapImmune,Inc. ... of innovative peptide and gene-based immunotherapeutics and vaccines for the ... be presenting at the 3rd Annual Growth Capital Expo ... th , 2016 at Caesars Palace in Las Vegas, Nevada.  ... on Wednesday, May 4 th by Dr. John ...
(Date:4/27/2016)...   , Total ... Consumable Sales  Clinical sales grow 16% year-over-year  ... MKEA, OTCQX: MKEAY) inventor of Cellvizio®, the multidisciplinary confocal ... first quarter ended March 31, 2016 and provided an ... commercial strategy. First Quarter 2016 Revenue Results ...
(Date:4/27/2016)... SHAWNEE, Kan. , April 27, 2016 /PRNewswire/ ... Martabano , a senior from the University of ... winner of the Bayer Excellence in Communication Award ... veterinary schools, which were awarded a total of ... Over the last four years, Bayer has provided ...
Breaking Medicine Technology: