Abstract
The characteristics of Ca2+ transport into endoplasmic reticulum vesicles isolated from roots of Lepidium sativum L. cv Krause have been investigated. The concentration of free Ca2+ and ATP needed for half-maximal activity were 2.5 and 73 micromolar, respectively, and the enzyme obeyed Michaelis-Menten-like kinetics. The pH maximum occurred at 7.5 and the activity was greatly reduced at either pH 7.0 or 8.0.
The Ca2+-dependent modulation protein, calmodulin, was tested for its effect on Ca2+ transport into endoplasmic reticulum vesicles. Although the phenothiazine inhibitors chlorpromazine, fluphenazine, and trifluoperazine all inhibited Ca2+ transport activity with a half-maximal effect at approximately 35 micromolar, authentic bovine brain calmodulin did not alter the activity at concentrations of 0.5 to 8 micrograms per milliliter. Calmodulin also showed no influence on the time-dependent accumulation of Ca2+ into vesicles. The membranes did not contain endogenously bound calmodulin since washing with (ethylenebis[oxyethylenenitrile])tetraacetic acid or fluphenazine, treatments which disrupt calmodulin binding, did not alter Ca2+ transport activity. The inhibition of Ca2+ transport by phenothiazine drugs was likely related to their nonspecific interaction with the membrane. Thus, there was no indication that calmodulin regulated Ca2+ uptake into root endoplasmic reticulum.
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- Bradford M. M. A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem. 1976 May 7;72:248–254. doi: 10.1016/0003-2697(76)90527-3. [DOI] [PubMed] [Google Scholar]
- Colca J. R., Kotagal N., Lacy P. E., McDaniel M. L. Comparison of the properties of active Ca2+ transport by the islet-cell endoplasmic reticulum and plasma membrane. Biochim Biophys Acta. 1983 Apr 6;729(2):176–184. doi: 10.1016/0005-2736(83)90483-2. [DOI] [PubMed] [Google Scholar]
- Dawson A. P., Fulton D. V. Some properties of the Ca2+-stimulated ATPase of a rat liver microsomal fraction. Biochem J. 1983 Feb 15;210(2):405–410. doi: 10.1042/bj2100405. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Gross J., Marmé D. ATP-dependent Ca uptake into plant membrane vesicles. Proc Natl Acad Sci U S A. 1978 Mar;75(3):1232–1236. doi: 10.1073/pnas.75.3.1232. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hodges T. K., Hanson J. B. Calcium Accumulation by Maize Mitochondria. Plant Physiol. 1965 Jan;40(1):101–109. doi: 10.1104/pp.40.1.101. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kubowicz B. D., Vanderhoef L. N., Hanson J. B. ATP-Dependent Calcium Transport in Plasmalemma Preparations from Soybean Hypocotyls : EFFECT OF HORMONE TREATMENTS. Plant Physiol. 1982 Jan;69(1):187–191. doi: 10.1104/pp.69.1.187. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Le Peuch C. J., Haiech J., Demaille J. G. Concerted regulation of cardiac sarcoplasmic reticulum calcium transport by cyclic adenosine monophosphate dependent and calcium--calmodulin-dependent phosphorylations. Biochemistry. 1979 Nov 13;18(23):5150–5157. doi: 10.1021/bi00590a019. [DOI] [PubMed] [Google Scholar]
- Niggli V., Adunyah E. S., Penniston J. T., Carafoli E. Purified (Ca2+-Mg2+)-ATPase of the erythrocyte membrane. Reconstitution and effect of calmodulin and phospholipids. J Biol Chem. 1981 Jan 10;256(1):395–401. [PubMed] [Google Scholar]
- Pershadsingh H. A., McDonald J. M. A high affinity calcium-stimulated magnesium-dependent adenosine triphosphatase in rat adipocyte plasma membranes. J Biol Chem. 1980 May 10;255(9):4087–4093. [PubMed] [Google Scholar]
- Plewe G., Jahn R., Immelmann A., Bode C., Söling H. D. Specific phosphorylation of a protein in calcium accumulating endoplasmic reticulum from rat parotid glands following stimulation by agonists involving cAMP as second messenger. FEBS Lett. 1984 Jan 23;166(1):96–103. doi: 10.1016/0014-5793(84)80052-6. [DOI] [PubMed] [Google Scholar]
- Raeymaekers L., Wuytack F., Eggermont J., De Schutter G., Casteels R. Isolation of a plasma-membrane fraction from gastric smooth muscle. Comparison of the calcium uptake with that in endoplasmic reticulum. Biochem J. 1983 Feb 15;210(2):315–322. doi: 10.1042/bj2100315. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Roufogalis B. D. Phenothiazine antagonism of calmodulin: a structurally-nonspecific interaction. Biochem Biophys Res Commun. 1981 Feb 12;98(3):607–613. doi: 10.1016/0006-291x(81)91157-8. [DOI] [PubMed] [Google Scholar]
- Schatzman R. C., Wise B. C., Kuo J. F. Phospholipid-sensitive calcium-dependent protein kinase: inhibition by antipsychotic drugs. Biochem Biophys Res Commun. 1981 Feb 12;98(3):669–676. doi: 10.1016/0006-291x(81)91166-9. [DOI] [PubMed] [Google Scholar]
- Schatzmann H. J. Dependence on calcium concentration and stoichiometry of the calcium pump in human red cells. J Physiol. 1973 Dec;235(2):551–569. doi: 10.1113/jphysiol.1973.sp010403. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sievers A., Behrens H. M., Buckhout T. J., Gradmann D. Can a Ca2+ pump in the endoplasmic reticulum of the Lepidium root be the trigger for rapid changes in membrane potential after gravistimulation? J Plant Physiol. 1984 Apr;114(3):195–200. doi: 10.1016/s0044-328x(84)80010-0. [DOI] [PubMed] [Google Scholar]
- Wolniak S. M., Hepler P. K., Jackson W. T. Detection of the membrane-calcium distribution during mitosis in Haemanthus endosperm with chlorotetracycline. J Cell Biol. 1980 Oct;87(1):23–32. doi: 10.1083/jcb.87.1.23. [DOI] [PMC free article] [PubMed] [Google Scholar]