Release of Ca 2+ from Individual Plant Vacuoles by Both InsP 3 and Cyclic ADP-Ribose

• Published in: Science (American Association for the Advancement of Science) Vol. 268; no. 5211; pp. 735 - 737
• Main Authors: Allen, Gethyn J., Muir, Shelagh R., Sanders, Dale
• Format: Journal Article
• Language: English
• Published: 05-05-1995
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.7732384

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 (
K
m
) = 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 (InsP
3
)-gated calcium release pathway in individual vacuoles.