Cell Migration  |  Integrins  |  How Integrins Work

How Integrins Work

Integrins can be thought of as velcro on the surface of the cell. When the cell is at rest, most of the integrins are inactive, that is to say they are present, but do not bind the ligands present in the ECM. Here is a representation of how this works:

picture courtesy Dr. Anne Cress, Arizona Cancer Center

When the cell decides to move, it turns on integrins in certain places, and turns them off in other places. Where this takes place depends on which direction the cell wants to move! Integrins on the "front" of the moving cell grip tightly to the ECM, pulling the cell forward. At the same time, the integrins in the back of the cell must "let go." These are taken up in the cell and recycled. The cell moves by "ruffling" it's membrane. This is done by a series of actin fibers, whose function is controlled by the integrins. These fibers cause the cell membrane to move in certain directions, and the integrins attach to the matrix as this happens, pulling the cell along a micrometer at a time! Here is a depiction of the complex interaction between integrins and actin fibers:

picture courtesy Giantcotti, et. al