An Actin Movie Star

What am I looking at?

The actin filaments in this so-called HeLa cell are labeled in red/orange, and the movement you see represents the dynamic, ever-changing nature of these filaments within the cell. The GI-SIM technique allows researchers to examine dynamic cellular processes like this in incredible detail.

Biology in the background

In all eukaryotic cells, actin protein assembles to form a network of thin filaments that spread throughout the cell. The actin filaments give the cell its structure, enable the cell to move, and allow for the formation of specialized structures that extend from the cell. These filaments are always forming, dissolving, and reforming depending on the needs of the cell.

A HeLa cell can range from 20 micrometers to 40 micrometers across, or roughly a quarter to half the width of a human hair, while actin filaments are tiny – only about 7 nanometers wide, or roughly 10,000 times smaller than the width of a human hair.

Technique

This video was created using grazing incidence structured illumination microscopy (GI-SIM), a type of fluorescence microscopy.