A Calcium-Selective Channel from Root-Tip Endomembranes of Garden Cress1
AUTOR(ES)
Klüsener, Birgit
FONTE
American Society of Plant Physiologists
RESUMO
A Ca2+ channel from root-tip endomembranes of garden cress (Lepidium sativum L.) (LCC1) was characterized using the planar lipid-bilayer technique. Investigation of single-channel recordings revealed that LCC1 is voltage gated and strongly rectifying. In symmetrical 50 mm CaCl2 solutions, the single-channel conductance was 24 picosiemens. LCC1 showed a moderate selectivity for Ca2+ over K+ (9.4:1) and was permeable for a range of divalent cations (Ca2+, Ba2+, and Sr2+). In contrast to Bryonia dioica Ca2+ channel 1, a Ca2+-selective channel from the endoplasmic reticulum of touch-sensitive tendrils, LCC1 showed no bursting channel activity and had a low open probability and mean open time (2.83 ms at 50 mV). Inhibitor studies demonstrated that LCC1 is blocked by micromolar concentrations of erythrosin B (inhibitor concentration for 50% inhibition [IC50] = 1.8 μm) and the trivalent cations La3+ (IC50 = 5 μm) and Gd3+ (IC50 = 10 μm), whereas verapamil showed no blocking effect. LCC1 may play an important role in the regulation of the cytoplasmic free Ca2+ concentration in root-tip and/or root-cap cells. The question of whether this ion channel is part of the gravitropic signal transduction pathway deserves further investigation.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=32025Documentos Relacionados
- Extrachromosomal DNA of pea (Pisum sativum) root-tip cells replicates by strand displacement
- Effects of Pterocaulon polystachyum DC. (Asteraceae) on onion (Allium cepa) root-tip cells
- Proof for a nonproteinaceous calcium-selective channel in Escherichia coli by total synthesis from (R)-3-hydroxybutanoic acid and inorganic polyphosphate
- A highly calcium-selective cation current activated by intracellular calcium release in MDCK cells.
- A highly calcium-selective cation current activated by intracellular calcium release in MDCK cells