Insights into cell movement likely to aid immune study, cance...( St. Louis Jan. 7 2007 Scientists at...),Health

St. Louis, Jan. 7, 2007 Scientists at Washington University School of Medicine in St. Louis have used yeast cells to better understand a collection of proteins associated with the formation of actin networks, which are essential to cell movement.

The cell's ability to move is important to a broad range of biomedical concerns, including understanding how immune system cells pursue disease-causing invaders and how metastasizing cancer cells migrate from a tumor.

"One of the bad things that cancer cells do is to walk away from where they're supposed to be," says senior author John Cooper, M.D., Ph.D., professor of cell biology and physiology. "If they didn't walk away, cancer would be something that you could just cut out, and that would be the end of it. So one hope is that if we learn more about how cancer cells are moving, we can someday try to block that process."

The study appears this month in Public Library of Science Biology.

In yeast, the proteins Cooper's lab studied regulate actin networks' contributions to a process called endocytosis. Yeast cells use this process to take in materials from their surface by forming pits on their cell membrane. Actin networks provide the push that forms these pits and drives them into the cell.

In more complex cells like those found in humans, the proteins have additional responsibilities that include helping regulate a process that cells use to thrust themselves forward. That process assembles many thin branching filaments of a polymer, actin, on the cell's surface. As these growing filaments reach nearby structures, they exert force that propels the cell in the desired direction.

Scientists know all the ingredients of actin networks, but they don't fully understand how the cell regulates their construction.

"One of the critical steps in generating an actin network is generating the seed of a new filament," says first author Brian Galletta, Ph.D., a postd
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