Adenosine triphosphate (ATP) is well-known for its role in cells as acting almost like currency for energy storage. Research by Elsa Matthus and colleagues shows that it can also play an important role outside the cell. Along with calcium, it may be how a plant can send stress signals from roots to leaves. The article shows that the DORN1/P2K1 receptor is critical in several calcium-related responses.
DORN1 got its name from the finding that it ‘DOes not Respond to Nucleotides(1)’ when it was found that it was a receptor, a structure in the cell membrane, that activated when ATP attached. The P2K1 element is a name that fits animal purino-receptor labelling system, While it does work with calcium for signalling, it is in fact very different from the receptors you would find in animals.
The team used Arabidopsis thaliana to get an idea of how calcium was passed along cells to send signals in the plant, and how ATP triggered calcium waves. What they found was that root cells had to have DORN1/P2K1 receptors to send signals. It’s interactions with ATP that drive a wave of calcium to the leaves, telling them what stresses the roots are under. However, leaves were only partially dependent on DORN1/P2K1.
“Overall, DORN1 still provides an important experimental gateway into the further dissection of purine–calcium signalling in roots and leaves,” write Matthus and colleagues. “However, comparisons with animal purino-signalling and some plant studies (including this) suggest that it is unlikely that DORN1 is the only purine nucleotide receptor in Arabidopsis.” The results suggest that there are potentially other DORNs to be found. If this is the case, it would be interesting to see how undiscovered DORN2 and DORNn interact with DORN1.