The purple in the center is the cell’s nucleus. Surrounding it are wispy blue and white microtubules and filaments that make up the cell’s cytoskeleton.
The cytoskeleton is made from protein structures called microtubules—the wispy threads surrounding the purple DNA-containing nucleus—and filaments of a protein called actin, seen here as the fine blue meshwork in the cell periphery. Both actin and microtubules are critical for growth and movement.
Unlike our own bony skeleton, which keeps the same arrangement throughout our lives, the cellular cytoskeleton is dynamic, continuously morphing in response to cellular signals. In this image, cytoskeleton remodeling of the skin cell was triggered by addition of a growth factor, which produced protrusions of the cell edge and the characteristic “fried egg” shape of this cell. These protrusions have little “feet” that help the cell move forward. The Wittmann lab recently used these skin cells to model the complex choreography by which microtubules control cell movement.