Cell Scaffolding

What am I looking at?

This is a video of a so-called HeLa cell that has been labeled (in red-orange) with a marker for an actin cross-linking protein. The color’s intensity corresponds to the protein’s density. In areas that are dark red or black, there is a very high concentration of the protein, and in areas that are light red or orange, there is a low concentration of the protein.

Biology in the background

Actin cross-linking proteins are responsible for organizing actin fibers into the scaffolding that allows a cell to move, change shape, and do much more. For example, in this video, you can see that the cross-linking proteins are enriched near the cell membrane and in the filopodia (these are the tendrils extending out from the cell membrane and waving around). Filopodia are specialized structures that allow a cell to explore the environment around it, among other things. The cross-linking proteins help organize the actin fibers in a way that allows other proteins to push the filopodia out into the environment and then to move once they’re extended.

These cross-linking proteins vary in size, but they are all extremely small – averaging about 3.5 nanometers, or roughly 22,000 times smaller than the width of a human hair.

Technique

This video was created using confocal microscopy.