Taking a peek inside the cell
For cooperative behavior to develop in human or cellular society, efficient communication is necessary. In cells, communication involves listening to external stimulus and translating it into intercellular signaling. We are interested in live imaging of the intercellular signaling pathways at single-cell resolution to gain insights into the communication underlying cooperative behavior; and modulating it to understand its role during disease development.
For example, one method of transducing intercellular signaling is via calcium ions. In this, the concentration of calcium ions increases in the cell’s cytoplasm in response to an external signal. Pancreatic beta-cell utilize this signaling pathway to tranlate increasing blood-glucose levels into insulin secretion.
The video shows a zebrafish pancreatic islet containing beta-cells whose nuclei are marked by expression of red fluorescent protein. In addition, the beta-cells express a genetically encoded sensor of calcium concentration, called GCaMP. GCaMP is not fluorescent at low calcium concentration, while it starts to emit green fluorescent light upon increasing calcium concentration.
The islet is exposed to increasing amount of glucose. In response, calcium ions rush into the cells and causes an increase of GCaMP-based green fluorescence. As we have single-cell resolution in this imaging setup, we can identify cells that are responsive to a specific concentration of glucose.