It turns out that wearing a cap is good for you, at least if you are a mammal cell.
Researchers from the Johns Hopkins Engineering in Oncology Center have shown that in healthy cells, a bundled "cap" of thread-like fibers holds the cell's nucleus, its genetic storehouse, in its proper place. Understanding this cap's influence on cell and nuclear shape, the researchers say, could provide clues to the diagnosis and treatment of diseases such as cancer, muscular dystrophy and the age-accelerating condition known as progeria.
"Under a microscope, the nucleus of a sick cell appears to bulge toward the top, while the nucleus of a healthy cell appears as a flattened disk that clings to the base," said principal investigator Denis Wirtz, professor of chemical and biomolecular engineering and director of the Engineering in Oncology Center. "If we can figure out how and why this shape-changing occurs, we may learn how to detect, treat or perhaps even prevent some serious medical disorders."
Scientists have known that misshapen nuclei are an indicator of disease, Wirtz said, but they were not certain how a cell controlled the shape of its nucleus, the structure in mammal cells where genetic material resides. In a study published in the Nov. 10 issue of the Proceedings of the National Academy of Sciences, however, the research team led by Wirtz reported the discovery of a fibrous structure that holds the nucleus in its place. The researchers call this new network structure the perinuclear actin cap.
"In healthy cells, the perinuclear actin cap is a domed structure of bundled filaments that sits above the nucleus, sort of like a net that is tethered all around to the perimeter of the cell membrane," Wirtz said. This configuration pushes the nucleus down toward the base of the cell and also creates the distinctive flattened shape of normal cells. Cells with cancer, muscular dystrophy or progeria, however, lack this distinctive cap
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Johns Hopkins University