Proteins are the helmsmen of the cell. They drive the essential processes that keep cells alive, keep them healthy and keep them functioning. And in recent years scientists have discovered that proteins rarely act alone.

In fact, so-called ‘protein-protein interactions’ are now known to drive the vast majority of cellular functions. But figuring out exactly how they do so has proven difficult.

Luckily, scientists now have a way to see these interactions—in a dazzling array of Technicolor.

As described in today’s issue of Nature Methods, Robert Campbell and his team at the University of Alberta have announced a new way to visualize protein-protein interactions, by converting these interactions into changes in color. This technique could be employed across a variety of disciplines, helping scientists understand normal processes in the cell—and observe the molecular changes that occur when those processes go awry.

“With this development,” explained Campbell in a news release, “we can immediately image activity happening at the cellular level, offering an alternative to existing methods for detecting and imaging of protein-protein interactions in live cells.”

Called FPX, Campbell’s method links a change in a protein-protein interaction to a color. As seen in the video below, every time the interaction changes, a color change—from red to green, and back to red again—is visible.

The FPX method is based on previously published work by Campbell and others, which found that green and red fluorescent proteins could both be inserted into a single cell so that the protein could be red or green—but not both at the same time. So, the team was able to construct biosensors that changed color in response to changes in protein-protein interactions.

In this study, the researchers have essentially given scientists a powerful tool to help them understand how even the smallest molecular changes can lead to significant changes in the health of the cell.

According to Campbell:

“It will be immediately relevant to many areas of fundamental cell biology research and practical applications such as drug discovery. Ultimately, it will help researchers achieve breakthroughs in a wide variety of areas in the life sciences, such as neuroscience, diabetes and cancer.”