Levels of Extracellular ATP in Growth Zones of Arabidopsis Primary Roots Are Changed by Altered Expression of Apyrase Enzymes

This study investigated the role of apyrase enzymes in regulating extracellular ATP (eATP) levels in the growth zones of Arabidopsis primary roots. Using an enzyme-based microsensor, researchers measured eATP concentrations near epidermal cell surfaces and found that eATP levels were highest in the elongation zone of wild-type roots. In transgenic Arabidopsis seedlings, mutants overexpressing or suppressing AtAPY1 and AtAPY2, which encode apyrases, showed altered eATP concentrations. The study concluded that eATP levels vary inversely with the expression of these apyrases, supporting the hypothesis that AtAPY1 and AtAPY2 regulate eATP levels in primary roots. Structural modeling suggested that these apyrases have active site configurations capable of binding ATP.