Science 5 May 1995:
Vol. 268 no. 5211 pp. 735-737
DOI: 10.1126/science.7732384
Release of Ca2+ from individual plant vacuoles by both InsP3 and cyclic ADP-ribose
GJ Allen, Muir, SR and D Sanders
+ Author Affiliations

Biology Department, University of York, UK.
Abstract
Calcium mobilization from intracellular pools couples many stimuli to responses in plant cells. Cyclic adenosine 5'-diphosphoribose (cADPR), which interacts with a ryanodine receptor in certain animal cells, was shown to elicit calcium release at the vacuolar membrane of beet storage root. The vacuolar calcium release pathway showed similarities to cADPR-gated calcium release in animal cells, including inhibition by ruthenium red, ryanodine activation, and high affinity for cADPR [Michaelis constant (Km) = 24 +/- 7 nanomolar]. Analysis by patch-clamping demonstrated that the cADPR-gated pathway in beet is voltage-dependent over the physiological range, does not spontaneously desensitize, and is colocalized with an inositol 1,4,5-trisphosphate (InsP3)-gated calcium release pathway in individual vacuoles. ·µ»ØСľ³æ²é¿´¸ü¶à