Ca2+ pump and Ca2+/H+ antiporter in plasma membrane vesicles isolated by aqueous two-phase partitioning from corn leaves
- 1 March 1990
- journal article
- research article
- Published by Springer Nature in The Journal of Membrane Biology
- Vol. 114 (2), 133-142
- https://doi.org/10.1007/bf01869094
Abstract
Summary Plasma membrane vesicles, which are mostly right side-out, were isolated from corn leaves by aqueous two-phase partitioning method. Characteristics of Ca2+ transport were investigated after preparing inside-out vesicles by Triton X-100 treatment.45Ca2+ transport was assayed by membrane filtration technique. Results showed that Ca2+ transport into the plasma membrane vesicles was Mg-ATP dependent. The active Ca2+ transport system had a high affinity for Ca2+(K m (Ca2+)=0.4 μm) and ATP(K m (ATP)=3.9 μm), and showed pH optimum at 7.5. ATP-dependent Ca2+ uptake in the plasma membrane vesicles was stimulated in the presence of Cl− or NO −3 . Quenching of quinacrine fluorescence showed that these anions also induced H+ transport into the vesicles. The Ca2+ uptake stimulated by Cl− was dependent on the activity of H+ transport into the vesicles. However, carbonylcyanidem-chlorophenylhydrazone (CCCP) and VO 3−4 which is known to inhibit the H+ pump associated with the plasma membrane, canceled almost all of the Cl−-stimulated Ca2+ uptake. Furthermore, artificially imposed pH gradient (acid inside) caused Ca2+ uptake into the vesicles. These results suggest that the Cl−-stimulated Ca2+ uptake is caused by the efflux of H+ from the vesicles by the operation of Ca2+/H+ antiport system in the plasma membrane. In Cl−-free medium, H+ transport into the vesicles scarcely occurred and the addition of CCCP caused only a slight inhibition of the active Ca2+ uptake into the vesicles. These results suggest that two Ca2+ transport systems are operating in the plasma membrane from corn leaves, i.e., one is an ATP-dependent active Ca2+ transport system (Ca2+ pump) and the other is a Ca2+/H+ antiport system. Little difference in characteristics of Ca2+ transport was observed between the plasma membranes isolated from etiolated and green corn leaves.Keywords
This publication has 47 references indexed in Scilit:
- Identification of a calmodulin‐stimulated (Ca2++ Mg2+)‐ATPase in a plasma membrane fraction isolated from maize (Zea mays) leavesPhysiologia Plantarum, 1988
- Tonoplast energization: Two H+ pumps, one membranePhysiologia Plantarum, 1987
- Characterization of the plasmalemma ATPase activity from roots of Plantago major ssp. pleiosperma, purified by the two-phase partitioning methodPhysiologia Plantarum, 1987
- Calcium messenger system in plantsCritical Reviews in Plant Sciences, 1987
- Pyridine nucleotide-dependent ferricyanide reduction associated with isolated plasma membranes of maize (Zea mays L.) rootsProtoplasma, 1986
- The measurement of intracellular calcium levels in protoplasts from higher plant cellsFEBS Letters, 1986
- An electrogenic uniport mediates light‐dependent Ca2+ influx into intact spinach chloroplastsFEBS Letters, 1985
- The Ca2+-pumping ATPase of plasma membranes purification, reconstitution and propertiesBiochimica et Biophysica Acta (BBA) - Reviews on Bioenergetics, 1982
- Light‐induced Ca2+ uptake by intact chloroplastsFEBS Letters, 1982
- A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye bindingAnalytical Biochemistry, 1976