Credit: Chutima Talchai, PhD/Columbia University Medical Center
The life cycle of transcription factor FoxO1 closely mirrors the state of health of the pancreatic beta cell. In a healthy cell, FoxO1 (stained red) is inactive and co-localizes with insulin (green) in the cytoplasm, giving rise to yellow color (left panel). In early diabetes, stress caused by elevated blood glucose is counteracted by the movement of FoxO1 to the nucleus, which allows cells to continue to produce insulin (middle panel). But if stress persists, this mechanism fails, in which case FoxO1 is degraded and insulin production ceases, giving rise to dedifferentiated beta cells (right panel).