Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scripps Research Scientists Define Cellular Pathway Essential to Removing Damaged Mitochondria

24.08.2011
New Findings Could Have Important Implications for Current Cancer Treatments

In a joint research effort with researchers at St. Jude Children’s Research Hospital, and with help from scientists at The University of Pennsylvania, The University of Minnesota, and the National Institutes of Health, investigators from the Florida campus of The Scripps Research Institute have defined a specific protein complex that allows cells to rid themselves of damaged mitochondria, which are the energy producing machines of the cell.

“This protein complex is already being targeted in cancer therapeutics,” said John Cleveland, chair of the Department of Cancer Biology at Scripps Florida, “but now we understand why some of the therapies that target this complex work and this new knowledge will have tremendous impact on both current and potential cancer therapies.”

In particular, the study, which appears in the current issue of the journal Molecular Cell, focuses on how the cell uses a process known as autophagy—the major recycling center of the cell—to remove damaged mitochondria. The autophagy pathway is exploited by many tumors to survive stressful conditions and to remove damaged components.

The Cell under Stress

On a molecular level, the new study focuses on the role of the molecular complex known as “Hsp90-Cdc37 chaperone complex,” which orchestrates various aspects of the cellular stress response. Although scientists had known that both the Hsp90-Cdc37 complex and autophagy help maintain the integrity of mitochondria, the exact relationship between Hsp90-Cdc37 and autophagy has not been well understood until the new study.

Hsp90, is a heat-shock protein, one of the cell’s most abundant proteins, and assists in everything from protein folding and tumor repression to cell signaling. Cdc37, also a protein, is a co-chaperone to Hsp90 and is involved in cell signal transduction and connecting Hsp90 to the right kinases (kinases add a phosphate group to various molecules and can modify protein activity).

The study highlights the interaction between Hsp90-Cdc37 and Ulk1, a kinase that the authors show is required for the degradation and elimination of damaged mitochondria. Hsp90-Cdc37 stabilizes and activates Ulk1, which in turn phosphorylates its substrate Atg13, which is then released from the complex. Atg13 then eliminates damaged mitochondria via the autophagy pathway. Thus, the study links Hsp90-Cdc37-Ulk1-Atg13 in a direct pathway that is essential for efficient mitochondrial clearance.

“The new study shows that the key regulatory mechanism of this process is the Hsp90-Cdc37 chaperone, which functions as an on-off switch that is critical for the correct functioning of the Ulk1 kinase,” Cleveland said. “Thus, if we can control this switch, we can significantly improve the therapeutic window.”

The first authors of the study, “Hsp90-Cdc37 Chaperone Complex RegulatesUlk1- and Atg13-mediated Mitophagy,” are Frank C. Dorsey of Scripps Research and Joung Hyuck Joo, Aashish Joshi, and Kristin M. Hennessy-Walters of St. Jude Children’s Research Hospital. Other authors include Kristie L. Rose, Stephanie M. Prater, Meredith A. Steeves, and John L. Cleveland of Scripps Research; Chang-Hwa Jung, and Do-Hyung Kim of the University of Minnesota; Der-Fen Suen, Chia-Ying Yang, Craig B. Thompson of the University of Pennsylvania School of Medicine; and Richard Youle of the National Institutes of Health; and Kelly McCastlain, Rekha Iyengar, Paul A. Ney and Mondira Kundu of St. Jude Children’s Research Hospital. For more information, see http://www.cell.com/molecular-cell/abstract/S1097-2765%2811%2900464-3 .

The study was supported by the National Institutes of Health, the Burroughs Welcome Fund, the American Society of Hematology, the Scripps Florida Funding Corporation, and the American Lebanese Syrian Associated Charities.

About The Scripps Research Institute

The Scripps Research Institute is one of the world's largest independent, non-profit biomedical research organizations. Scripps Research is internationally recognized for its discoveries in immunology, molecular and cellular biology, chemistry, neuroscience, and vaccine development, as well as for its insights into autoimmune, cardiovascular, and infectious disease. Headquartered in La Jolla, California, the institute also includes a campus in Jupiter, Florida, where scientists focus on drug discovery and technology development in addition to basic biomedical science. Scripps Research currently employs about 3,000 scientists, staff, postdoctoral fellows, and graduate students on its two campuses. The institute's graduate program, which awards Ph.D. degrees in biology and chemistry, is ranked among the top ten such programs in the nation. For more information, see www.scripps.edu.

For information:
Eric Sauter
Tel: 215-862-2689
erics165@comcast.net
Mika Ono
Tel: 858-784-2052
Fax: 858-784-8136
mikaono@scripps.edu

Eric Sauter | EurekAlert!
Further information:
http://www.scripps.edu

More articles from Life Sciences:

nachricht How cells hack their own genes
24.08.2017 | IMBA - Institut für Molekulare Biotechnologie der Österreichischen Akademie der Wissenschaften GmbH

nachricht What the world's tiniest 'monster truck' reveals
23.08.2017 | American Chemical Society

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

What the world's tiniest 'monster truck' reveals

23.08.2017 | Life Sciences

Treating arthritis with algae

23.08.2017 | Life Sciences

Witnessing turbulent motion in the atmosphere of a distant star

23.08.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>