Scientists at Rice University have developed a way to watch protein changes in living cells using a special amino acid that glows. This method works in bacteria, human cells, and tumor models, helping study diseases like cancer without harming cells. Proteins control many body functions, like growth and aging. Changes to proteins, called posttranslational modifications (PTMs), act like switches that turn these functions on or off. Until now, tracking these changes was hard without breaking cells or using complex methods.
The new approach, published in Nature Communications, involves engineering cells to make a glowing version of an amino acid called lysine. Amino acids are the building blocks of proteins. When PTMs happen, the glowing lysine shows the changes in real time, letting scientists see how proteins work inside living systems. This is a big step forward because it avoids using harsh chemicals or methods that disrupt cells.
Chromophoric proof and cancer insights
The researchers started with the idea that cells could make their own glowing amino acid, instead of adding synthetic labels from outside. They used enzymes to create a special form of lysine called acetyllysine inside cells. By genetically modifying bacteria and human cells, they made proteins include this glowing lysine at specific spots. Special reporter proteins, like fluorescent proteins, light up when PTMs occur, proving the system works for tracking changes instantly.
To test the method, the scientists studied a protein called SIRT1, which controls inflammation and is linked to cancer. They found that blocking SIRT1 stopped its activity but didn’t always slow tumor growth, challenging some existing ideas. The glowing system made these findings visible in living tissue, offering a clear view of protein behavior.
This technology could change how scientists study PTMs in diseases like cancer, aging, or brain disorders. It allows real-time tracking in living organisms and works well for testing new drugs. In the future, it might be used for other PTM types or in lab-grown human tissues, helping create personalized treatments and better understanding of how cells work.