Johns Hopkins scientists have discovered the molecular sensor that lets cells not only "feel" changes to their shapes, but also helps them regain their ready-to-split symmetry. In a study published September 15 in
Current Biology, the researchers explain that two force-sensitive proteins accumulate at the sites of cell-shape disturbances and cooperate first to sense the changes and then to resculpt the cells. The proteins � myosin II and cortexillin I � monitor and correct shape changes in order to ensure smooth division.
"What we found is an exquisitely tuned mechanosensory system that keeps the cells shipshape so they can divide properly," says Douglas N. Robinson, Ph.D., an associate professor of Cell Biology, Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine.
Faulty cell division can put organisms, including people, on the pathway to diseases such as cancer. Abetter understanding of how cells respond to mechanical stress on their shapes could lead to new technologies for diagnosing and treating such diseases.
Researchers worked with single-celled protozoa that move and divide similarly to human cells, and watched through microscopes while they deformed the cells' shapes with a tiny instrument that, like a soda straw, sucks in on the cell surface and creates distorted shapes.
During the experiments, as soon as the two proteins accumulated to a certain level, the cells contracted, escaped the pipettes and reassumed their original shapes. Once the cells had returned to their proper shape, the accumulated proteins realigned along the cells' midlines and pinched to divide symmetrically into two daughter cells.
Writer: Walaika Haskins
Source: Douglas Robinson, JHUSM