Release of Ca2+ from individual plant vacuoles by both InsP3 and cyclic ADP-ribose.
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.
Allen
G J
GJ
Biology Department, University of York, UK.
Muir
S R
SR
Sanders
D
D
D000246:Adenosine Diphosphate Ribose / Q000031:analogs & derivatives* / Q000502:physiology; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000502:physiology; D036563:Cyclic ADP-Ribose; D015544:Inositol 1,4,5-Trisphosphate / Q000502:physiology*; D015640:Ion Channel Gating / Q000502:physiology; D008564:Membrane Potentials / Q000502:physiology; D009124:Muscle Proteins / Q000502:physiology; D010940:Plant Proteins / Q000502:physiology; D010944:Plants / Q000378:metabolism*; D019837:Ryanodine Receptor Calcium Release Channel; D015398:Signal Transduction / Q000502:physiology; D014617:Vacuoles / Q000378:metabolism*; D014675:Vegetables / Q000378:metabolism
D015220:Calcium Channels; D009124:Muscle Proteins; D010940:Plant Proteins; D019837:Ryanodine Receptor Calcium Release Channel; D036563:Cyclic ADP-Ribose; D000246:Adenosine Diphosphate Ribose; D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium