Abstract
The effect of controlled proteolysis on the plasma membrane (PM)Ca2+-ATPase was studied at the molecular level in PM purified from radish (Raphanus sativus L.) seedlings. Two new methods for labeling the PM Ca2+-ATPase are described. The PM Ca2+-ATPase can be selectively labeled by treatment with micromolar fluorescein isothiocyanate (FITC), a strong inhibitor of enzyme activity. Both inhibition of activity and FITC binding to the PM Ca2+-ATPase are suppressed by millimolar MgITP. The PM Ca2+-ATPase maintains the capability to bind calmodulin also after sodium dodecyl sulfate gel electrophoresis and blotting; therefore, it can be conveniently identified by 125l-calmodulin overlay in the presence of calcium. With both methods a molecular mass of 133 kD can be calculated for the PM Ca2+-ATPase. FITC-labeled PM Ca2+-ATPase co-migrates with the phosphorylated intermediate of the enzyme[mdash]labeled by incubation with [[gamma]-32P]GTP in the presence of calcium[mdash]on acidic sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Controlled trypsin treatment of purified PM determines a reduction of the molecular mass of the PM Ca2+-ATPase from 133 to 118 kD parallel to the increase of enzyme activity. Only the 133-kD but not the 118-kD PM Ca2+-ATPase binds calmodulin. These results indicate that trypsin removes from the PM Ca2+-ATPase an autoinhibitory domain that contains the calmodulin-binding domain of the enzyme.
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- Askerlund P., Evans D. E. Reconstitution and Characterization of a Calmodulin-Stimulated Ca-Pumping ATPase Purified from Brassica oleracea L. Plant Physiol. 1992 Dec;100(4):1670–1681. doi: 10.1104/pp.100.4.1670. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Carnelli A., De Michelis M. I., Rasi-Caldogno F. Plasma Membrane Ca-ATPase of Radish Seedlings : I. Biochemical Characterization Using ITP as a Substrate. Plant Physiol. 1992 Mar;98(3):1196–1201. doi: 10.1104/pp.98.3.1196. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Chen F. H., Ratterman D. M., Sze H. A Plasma Membrane-Type Ca2+-ATPase of 120 Kilodaltons on the Endoplasmic Reticulum from Carrot (Daucus carota) Cells (Properties of the Phosphorylated Intermediate). Plant Physiol. 1993 Jun;102(2):651–661. doi: 10.1104/pp.102.2.651. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dux L., Papp S., Martonosi A. Conformational responses of the tryptic cleavage products of the Ca2+-ATPase of sarcoplasmic reticulum. J Biol Chem. 1985 Nov 5;260(25):13454–13458. [PubMed] [Google Scholar]
- Hsieh W. L., Pierce W. S., Sze H. Calcium-pumping ATPases in vesicles from carrot cells : stimulation by calmodulin or phosphatidylserine, and formation of a 120 kilodalton phosphoenzyme. Plant Physiol. 1991 Dec;97(4):1535–1544. doi: 10.1104/pp.97.4.1535. [DOI] [PMC free article] [PubMed] [Google Scholar]
- James P., Vorherr T., Krebs J., Morelli A., Castello G., McCormick D. J., Penniston J. T., De Flora A., Carafoli E. Modulation of erythrocyte Ca2+-ATPase by selective calpain cleavage of the calmodulin-binding domain. J Biol Chem. 1989 May 15;264(14):8289–8296. [PubMed] [Google Scholar]
- Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
- Luterbacher S., Schatzmann H. J. The site of action of La3+ in the reaction cycle of the human red cell membrane Ca2+-pump ATPase. Experientia. 1983 Mar 15;39(3):311–312. doi: 10.1007/BF01955322. [DOI] [PubMed] [Google Scholar]
- Markwell M. A., Haas S. M., Bieber L. L., Tolbert N. E. A modification of the Lowry procedure to simplify protein determination in membrane and lipoprotein samples. Anal Biochem. 1978 Jun 15;87(1):206–210. doi: 10.1016/0003-2697(78)90586-9. [DOI] [PubMed] [Google Scholar]
- Poovaiah B. W., Reddy A. S. Calcium and signal transduction in plants. CRC Crit Rev Plant Sci. 1993;12(3):185–211. doi: 10.1080/07352689309701901. [DOI] [PubMed] [Google Scholar]
- Rasi-Caldogno F., Carnelli A., De Michelis M. I. Controlled Proteolysis Activates the Plasma Membrane Ca2+ Pump of Higher Plants (A Comparison with the Effect of Calmodulin in Plasma Membrane from Radish Seedlings). Plant Physiol. 1993 Oct;103(2):385–390. doi: 10.1104/pp.103.2.385. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rasi-Caldogno F., Carnelli A., De Michelis M. I. Plasma Membrane Ca-ATPase of Radish Seedlings : II. Regulation by Calmodulin. Plant Physiol. 1992 Mar;98(3):1202–1206. doi: 10.1104/pp.98.3.1202. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rasi-Caldogno F., Pugliarello M. C., De Michelis M. I. The Ca-Transport ATPase of Plant Plasma Membrane Catalyzes a nH/Ca Exchange. Plant Physiol. 1987 Apr;83(4):994–1000. doi: 10.1104/pp.83.4.994. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rasi-Caldogno F., Pugliarello M. C., Olivari C., De Michelis M. I. Identification and Characterization of the Ca-ATPase which Drives Active Transport of Ca at the Plasma Membrane of Radish Seedlings. Plant Physiol. 1989 Aug;90(4):1429–1434. doi: 10.1104/pp.90.4.1429. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Schatzmann H. J. The calcium pump of the surface membrane and of the sarcoplasmic reticulum. Annu Rev Physiol. 1989;51:473–485. doi: 10.1146/annurev.ph.51.030189.002353. [DOI] [PubMed] [Google Scholar]
- Thomson L. J., Hall J. L., Williams L. E. A Study of the Effect of Inhibitors of the Animal Sarcoplasmic/Endoplasmic Reticulum-Type Calcium Pumps on the Primary Ca2+-ATPases of Red Beet. Plant Physiol. 1994 Apr;104(4):1295–1300. doi: 10.1104/pp.104.4.1295. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Williams L. E., Schueler S. B., Briskin D. P. Further Characterization of the Red Beet Plasma Membrane Ca-ATPase Using GTP as an Alternative Substrate. Plant Physiol. 1990 Mar;92(3):747–754. doi: 10.1104/pp.92.3.747. [DOI] [PMC free article] [PubMed] [Google Scholar]