Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Protein key to cell motility has implications for stopping cancer metastasis

13.03.2014

"Cell movement is the basic recipe of life, and all cells have the capacity to move," says Roberto Dominguez, PhD, professor of Physiology at the Perelman School of Medicine, University of Pennsylvania.

Motility – albeit on a cellular spatial scale -- is necessary for wound healing, clotting, fetal development, nerve connections, and the immune response, among other functions. On the other hand, cell movement can be deleterious when cancer cells break away from tumors and migrate to set up shop in other tissues during cancer metastasis.

The States of IRSp53

This image shows the active, open state of IRSp53 (top) and inactive, closed (bottom) state of IRSp53. In the closed state, cells do not generate filopodia as shown in the right bottom image (green=IRSp53, red=cdc42, and blue=actin, the most abundant protein in the cytoskeleton). The arrow between the two states indicates that the synergistic binding of Cdc42, cytoskeleton proteins (called downstream effectors of IRSp53 and includes the tumor-promoting factor Eps8) and the inherent attraction for the cell membrane, bring IRSp53 to specific locations on the cell membrane in which to change the shape of the cell. Chief among this reshaping activity is generating filopodia, the long thin objects coming off the cell in the top right image (color scheme as right bottom image). Note the change in pattern of the green and red show that IRSp53 and cdc42 are working together and moving to many different locations around the cell.

Credit: Roberto Dominguez, Ph.D., David Kast, Ph.D., Perelman School of Medicine, University of Pennsylvania

The Dominguez team, with postdoctoral fellow David Kast, PhD, and colleagues, report online ahead of print in Nature Structural & Molecular Biology how a key cell-movement protein called IRSp53 is regulated in a resting and active state, and what this means for cancer-cell metastasis.

"We characterized how IRSp53 connects to the cell-motility machinery," says Kast. "It does this by starting the formation of cell filopodia - extensions that form when a cell needs to move."

"Cells move like an inchworm," explains Dominguez. "Filopodia are at the leading edge of moving cells." The trailing end of the cell follows the move forward through contraction of actin and myosin in the cytoskeleton, much like muscle contraction. A cell pushes out the leading edge of its membrane, and sticks it down on whatever it is moving across, namely other cells, and then moves the cell body along, unsticking the back end. This sets the cell up for its next move.

IRSp53 contains a region called a BAR domain that binds to and shapes cell membranes. Other parts of the protein connect it to the cytoskeleton (internal bits that give a cell structure and shape). Together, through the binding of cell membranes and other proteins IRSp53 regulates cell movement. The team found that in the resting state, human IRSp53 adopts a closed shape that prevents it from interacting with the membrane and the cytoskeleton. However, the binding of a signaling protein, called Cdc42, opens IRSp53, setting in motion the recruitment of a complex cellular machinery needed for motility.

One of the cytoskeleton components IRSp53 connects to is the tumor-promoting protein Eps8. IRSp53 is synergistically activated by the combined action of Cdc42 and binding of Eps8, which is upregulated in metastatic cancers.

Co-authors Tatyana Svitkina and Changsong Yang from the Penn Department of Biology, brought their expertise with living cells to the study. By introducing normal and mutant proteins into cells they could see how these proteins induced filopodia to form. The team found that mutations in critical regions of IRSp53 can either lead to enhanced or reduced filopodia formation and, as a consequence, cell motility. "This finding shows how all these different proteins converge on IRSp53 to execute precise cellular functions, and that when one factor is disrupted, other proteins are affected down the activity pathway," says Dominguez.

The team's next steps will be to screen libraries of small molecule inhibitors that interfere with the IRSp53-Eps8 interaction, to figure out how to stop unwanted cell movement before it gets too far.

Coauthors include Yadaiah Madasu and Malgorzata Boczkowska, also from Physiology, and Andrea Disanza and Giorgio Scita from the Institute of Molecular Oncology and the University of Milan School of Medicine in Italy.

The research was funded by the National Institutes of Health (R01 MH087950, T32 AR053461, GM095977) and the American Cancer Society (PF-13-033-01-DMC).

Penn Medicine is one of the world's leading academic medical centers, dedicated to the related missions of medical education, biomedical research, and excellence in patient care. Penn Medicine consists of the Raymond and Ruth Perelman School of Medicine at the University of Pennsylvania (founded in 1765 as the nation's first medical school) and the University of Pennsylvania Health System, which together form a $4.3 billion enterprise.

The Perelman School of Medicine has been ranked among the top five medical schools in the United States for the past 17 years, according to U.S. News & World Report's survey of research-oriented medical schools. The School is consistently among the nation's top recipients of funding from the National Institutes of Health, with $392 million awarded in the 2013 fiscal year.

The University of Pennsylvania Health System's patient care facilities include: The Hospital of the University of Pennsylvania -- recognized as one of the nation's top "Honor Roll" hospitals by U.S. News & World Report; Penn Presbyterian Medical Center; Chester County Hospital; Penn Wissahickon Hospice; and Pennsylvania Hospital -- the nation's first hospital, founded in 1751. Additional affiliated inpatient care facilities and services throughout the Philadelphia region include Chestnut Hill Hospital and Good Shepherd Penn Partners, a partnership between Good Shepherd Rehabilitation Network and Penn Medicine.

Penn Medicine is committed to improving lives and health through a variety of community-based programs and activities. In fiscal year 2013, Penn Medicine provided $814 million to benefit our community.

Karen Kreeger | EurekAlert!
Further information:
http://www.uphs.upenn.edu

Further reports about: Medicine cytoskeleton filopodia implications metastasis motility proteins

More articles from Life Sciences:

nachricht Novel 'repair system' discovered in algae may yield new tools for biotechnology
29.07.2016 | Boyce Thompson Institute

nachricht Molecular troublemakers instead of antibiotics?
29.07.2016 | Christian-Albrechts-Universität zu Kiel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Self-assembling nano inks form conductive and transparent grids during imprint

Transparent electronics devices are present in today’s thin film displays, solar cells, and touchscreens. The future will bring flexible versions of such devices. Their production requires printable materials that are transparent and remain highly conductive even when deformed. Researchers at INM – Leibniz Institute for New Materials have combined a new self-assembling nano ink with an imprint process to create flexible conductive grids with a resolution below one micrometer.

To print the grids, an ink of gold nanowires is applied to a substrate. A structured stamp is pressed on the substrate and forces the ink into a pattern. “The...

Im Focus: The Glowing Brain

A new Fraunhofer MEVIS method conveys medical interrelationships quickly and intuitively with innovative visualization technology

On the monitor, a brain spins slowly and can be examined from every angle. Suddenly, some sections start glowing, first on the side and then the entire back of...

Im Focus: Newly discovered material property may lead to high temp superconductivity

Researchers at the U.S. Department of Energy's (DOE) Ames Laboratory have discovered an unusual property of purple bronze that may point to new ways to achieve high temperature superconductivity.

While studying purple bronze, a molybdenum oxide, researchers discovered an unconventional charge density wave on its surface.

Im Focus: Mapping electromagnetic waveforms

Munich Physicists have developed a novel electron microscope that can visualize electromagnetic fields oscillating at frequencies of billions of cycles per second.

Temporally varying electromagnetic fields are the driving force behind the whole of electronics. Their polarities can change at mind-bogglingly fast rates, and...

Im Focus: Continental tug-of-war - until the rope snaps

Breakup of continents with two speed: Continents initially stretch very slowly along the future splitting zone, but then move apart very quickly before the onset of rupture. The final speed can be up to 20 times faster than in the first, slow extension phase.phases

Present-day continents were shaped hundreds of millions of years ago as the supercontinent Pangaea broke apart. Derived from Pangaea’s main fragments Gondwana...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Clash of Realities 2016: 7th Conference on the Art, Technology and Theory of Digital Games

29.07.2016 | Event News

GROWING IN CITIES - Interdisciplinary Perspectives on Urban Gardening

15.07.2016 | Event News

SIGGRAPH2016 Computer Graphics Interactive Techniques, 24-28 July, Anaheim, California

15.07.2016 | Event News

 
Latest News

Vortex laser offers hope for Moore's Law

29.07.2016 | Power and Electrical Engineering

Novel 'repair system' discovered in algae may yield new tools for biotechnology

29.07.2016 | Life Sciences

Clash of Realities 2016: 7th Conference on the Art, Technology and Theory of Digital Games

29.07.2016 | Event News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>