A Perspective On A Promising Role For Caffeine In Modulating The Casr In Pancreatic Β-Cells

The extracellular calcium-sensing receptor (CaSR) is a G-protein-coupled receptor (GPCR) that plays a crucial role in the parathyroid glands and kidneys in maintaining calcium (Ca2+) homeostasis. The extracellular CaSR is present in various cell types not implicated in controlling plasma Ca2+ levels. There is accumulating evidence that CaSR plays a significant role in regulating the function of β-cells in the pancreas. Divalent cations and insulin are released together during exocytosis, and their concentration in the restricted intercellular compartments of the pancreatic islet increases to activate CaSR in neighboring cells. Subsequently, the activated CaSR stimulates insulin vesicle release in the adjacent cells, and by repeating these steps, the signal is amplified in the whole islet. Recent work developed a photoaffinity-tagged glutathione derivative (DAZ-G) as a chemical tool. The study demonstrated that DAZ-G can identify and analyze CaSR ligands. The use of DAZ-G identified caffeine as a positive allosteric modulator of the CaSR, suggesting that the physiological effects of caffeine are partly attributed to its stimulation of the CaSR. Future work may utilize caffeine to activate the CaSR in pancreatic β-cells to improve their secretory function