Navigation Links
Virus mimics human protein to hijack cell division machinery

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
University of Wisconsin-Madison

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
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:
(Date:6/24/2016)... ... June 24, 2016 , ... People across the U.S. are ... Code Talker Award, an essay contest in which patients and their families pay tribute ... presented at the 2016 National Society of Genetic Counselors (NSGC) Annual Education Conference (AEC) ...
(Date:6/24/2016)... ... June 24, 2016 , ... The Haute Beauty ... Barry M. Weintraub as a prominent plastic surgeon and the network’s newest partner. ... and the most handsome men, look naturally attractive. Plastic surgery should be invisible.” ...
(Date:6/24/2016)... ... June 24, 2016 , ... Strategic Capital Partners, ... economy by obtaining investment capital for emerging technology companies. SCP has delivered ... already resulted in more than a million dollars of capital investment for five ...
(Date:6/24/2016)... ... June 24, 2016 , ... Venture Construction Group (VCG) ... held on June 20th at the Woodmont Country Club at 1201 Rockville Pike, ... organization dedicated to helping service members that have been wounded in battle and their ...
(Date:6/24/2016)... ... June 24, 2016 , ... Advanced Plastic Surgery Institute ( ... as its official Medspa Sponsor. Dr. Josh Olson, a board-certified plastic surgeon, owns ... Dr. Olson says the decision to support the pageant in an official capacity ...
Breaking Medicine News(10 mins):
(Date:6/24/2016)... June 24, 2016 The Academy of Managed ... recommendations that would allow biopharmaceutical companies to more ... that make formulary and coverage decisions, a move that ... new medicines. The recommendations address restrictions in ... on the drug label, a prohibition that hinders decision ...
(Date:6/24/2016)... 2016 Research and Markets has announced ... Diagnostic Tests" report to their offering. ... The World Market for Companion Diagnostics covers ... Market analysis in the report includes the following: ... Diagnostic Kits) by Region (N. America, EU, ROW), 2015-2020 ...
(Date:6/24/2016)... , June 24, 2016 ... appointment of Dr. Edward Futcher to ... Director, effective June 23, 2016.Dr. Futcher was also ... and Governance Committees.  As a non-executive member of ... expertise and strategic counsel to VolitionRx in connection ...
Breaking Medicine Technology: