Biology textbooks tend to describe cell identity as a one-way trip. A stem cell becomes a specialized cell, and that is the end of the story. The lining of the human intestine has never fully obeyed that rule, and researchers at Memorial Sloan Kettering Cancer Center have now identified a protein that appears to govern the exception.
The protein is ZFP36L2, an RNA-binding molecule the team describes as a molecular switch connecting the gut's damage-sensing system to a cell's ability to change what it is. When intestinal stem cells are wiped out by inflammation, infection, or injury, mature specialized cells can revert to a stem-like state and rebuild the stem cell pool. ZFP36L2 makes that reversal possible.
