University of Florida, Gainesville, FL 32611
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Extracts

UF Engineers use microsurgery to study the mechanics of a cell

By Donna Hesterman

A team of researchers in UF’s chemical engineering department have taken a novel approach to exploring the inner mechanics of a living animal cell.

Using laser scissors to make a precise microscopic cut, Jun Wu, a doctoral student in chemical engineering, carefully sliced one of the stiff spindly spokes that grow out from a cell’s architectural hub, the centrosome, to find out how a cell finds its center.

“There are really two schools of thought about how microtubules work together to move the centrosome to the center of the cell,” explained Richard Dickinson, professor and chair of UF’s chemical engineering department, who is the senior author on the research paper. “One view is that the spokes, or micro-tubules, push the centrosome toward the center as they grow out from the hub and push against the cell’s outer membrane. The other view is that the microtubules pull the centrosome into place using tiny molecular motors arranged in a series along the microtubules’ length.

“When cut, one of the ends would always bend further rather than snapping straight,” said co-author Tanmay Lele, assistant professor of chemical engineering.

And that told the team they were onto something.

The reaction implied that the microtubules were under tension, a bit like a stretched rubber band, and that they were pulling rather than pushing the centrosome.

“It tells us something important about how cells locate their center,” said Dickinson. “Like a game of tug-of-war, with the microtubules acting as the ropes, the motors pull on the microtubules extending from both sides of the centrosome.”

When the centrosome is off-center, the longer microtubules on the side farthest from the cell edge pull harder and thereby always bring the centrosome back toward the center. And that can be important for understanding how cells replicate and carry out other biologically vital missions.

The full report on the team’s study was published in the online edition of the journal Molecular Biology of the Cell.

Richard Dickinson, dickinso@ufl.edu
Tanmay Lele, tlele@che.ufl.edu