The inmost tug7/17/2023 The most likely explanation, they conclude, is that the electric field causes certain electrically charged proteins in the cell membrane to concentrate at the membrane edge, triggering a response. In a separate paper to be published in the same journal issue, Mogilner and Stanford University researchers Greg Allen and Julie Theriot narrow down the possible mechanisms. Upstream of those two pathways is some kind of sensor that detects the electric field. At least one of the pathways-leading to organized actin/myosin fibers-can work without a cell nucleus or any of the other organelles found in cells, beyond the cell membrane and proteins that make up the cytoskeleton. The results show that there are at least two distinct pathways through which cells respond to electric fields, Mogilner says. But in cell fragments, the actin/myosin motor came out on top, got the rear of the cell oriented toward the cathode, and the cell fragment crawled in the opposite direction. In whole cells, the actin mechanism won, and the cell crawled toward the cathode. The polarizing effect set up a tug-of-war between the two mechanisms. Both actin alone, and actin with myosin, can create motors that drive the cell forward. Cells crawl along surfaces by sliding and ratcheting protein fibers inside the cell past each other, advancing the leading edge of the cell while withdrawing the trailing edge.Īssistant project scientist Yaohui Sun found that when whole cells were exposed to an electric field, actin protein fibers collected and grew on the side of the cell facing the negative electrode (cathode), while a mix of contracting actin and myosin fibers formed toward the positive electrode (anode). Think of a cell as a blob of fluid and protein gel wrapped in a membrane. That allowed the researchers to discover that the cells and cell fragments are oriented by a “tug of war” between two competing processes. It’s the first time that such basic cell fragments have been shown to orient and move in an electric field, Mogilner says. In a surprise discovery, whole cells and cell fragments moved in opposite directions in the same electric field, says Alex Mogilner, professor of mathematics and of neurobiology, physiology, and behavior and co-senior author of the paper. These fish cells are commonly used to study cell motion, and they also readily shed cell fragments, wrapped in a cell membrane but lacking a nucleus, major organelles, DNA, or much else in the way of other structures. ![]() The researchers worked with cells that form fish scales, called keratocytes. “If we can understand the process better, we can make wound healing and tissue regeneration more effective.” “We know that cells can respond to a weak electrical field, but we don’t know how they sense it,” says Min Zhao, professor of dermatology and ophthalmology and a researcher at University of California, Davis Institute for Regenerative Cures. But exactly how and why does this happen? That’s unclear. Damage to tissue sets up a “short circuit,” changing the flux direction and creating an electrical field that leads cells into the wound. In healthy tissue there’s a flux of charged particles between layers. ![]() When cells crawl into wounded flesh to heal it, they follow an electric field. The study, published in the journal Current Biology, could ultimately lead to new ways to heal wounds and deliver stem cell therapies. UC DAVIS (US) - Like tiny, crawling compass needles, whole living cells and cell fragments orient and move in response to electric fields-but in opposite directions, scientists report. University University of California, Davis
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