Doing the Wave

What am I looking at?

This video shows a cytoskeletal mechanism called an actin wave in a so-called HeLa cell. The actin filaments are orange, and you can see a wave of bright orange traveling around the periphery of the cell. The mitochondria are blue, and some of them appear to move with or be shifted by the actin wave.

Click on the right arrow to see another video that shows an overlay with both actin and mitochondria on the left, just actin in the middle, and just mitochondria on the right.

Biology in the background

In all eukaryotic cells, actin proteins come together to form a network of thin filaments that spread throughout the cell. These filaments play a role in the cell’s structure and movement, its transport of organelles, and more. The actin wave phenomenon and its functions are still not fully understood, though some research has shown that it’s involved in cellular division; in the formation of protrusions from the cell, such as lamellipodia and filopodia; and in the movement of the cell within its environment. There is also evidence that the cycling wave acts almost like a card dealer shuffling a deck of cards before dealing - it randomizes the position of mitochondria in space to ensure random inheritance during cell division.

A HeLa cell can range from 20 micrometers to 40 micrometers across, or roughly a quarter to half the width of a human hair.

Technique

This video was created using confocal microscopy.