How cells know when to stop wound-healing

Researchers have found that an integrin -- a protein that helps cells stick to surfaces -- also tells cells when they should stop healing a wound and settle down.

Vito Quaranta (The Scripps Research Institute, La Jolla, California) and colleagues report in the April 30 issue of The Journal of Cell Biology that they looked at two different integrins on skin cells. The first integrin, called alpha(3)beta(1), helps cells respond to chemical signals that are generated by a wound. The chemical signals and the integrin cooperate, resulting in movement of cells into the large gap produced by the wound.

As the cells move into the wound, they lay down a sticky bed of proteins including laminin 5. The chemical signals dissipate as the wound heals, but to fine-tune their position the cells now use alpha(3)beta(1) to crawl over the laminin 5.

At some stage, however, the cells need to stop moving and settle down. This is where another integrin, called alpha(6)beta(4), comes in. This second integrin can also grab onto the laminin 5 surface. Quaranta and colleagues found that the second integrin did not interfere with the initial cell movement (in response to the chemical signals), but did interfere with movement over laminin 5, by turning off the instructions generated by the first integrin. This action ensures that the movement instructions from the first integrin are never in conflict with the anchoring instructions from the second integrin.

Contact: Vito Quaranta, The Scripps Research Institute, La Jolla, California, 858-784-8793, quaranta@scripps.edu