Abstract
1. Ruthenium Red-insensitive Ca2+ transport in the mouse ascites sarcoma 180/TG is enriched in a 'heavy' microsomal fraction (microsomes) sedimented at 35 000 g for 20 min. The subcellular distribution of this Ca2+ transport differed from that of Ruthenium Red-sensitive Ca2+ transport and (Na+ + K+)-dependent ATPase activity, but was similar to that of glucose 6-phosphatase. 2. The affinity of this transport system for 'free' Ca2+ is high (Km approx. 6 microM) and that for MgATP somewhat lower (Km approx. 100 microM). Ca2+ transport by the tumour microsomes, by contrast with that by liver microsomes, was greatly stimulated by low concentrations of P1. 3. Although incubation of intact ascites cells with glucagon led to an increase in intracellular cyclic AMP, no stable increase in the initial rate of Ca2+ transport in the subsequently isolated 'heavy' microsomes could be detected as in similar experiments carried out previously with rat liver cells. Reconstitution experiments suggest that a deficiency exists in the tumour microsomal membrane such that an action of glucagon that is normally present in rat liver microsomes is not evoked.
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- Ash G. R., Bygrave F. L. Ruthenium red as a probe in assessing the potential of mitochondria to control intracellular calcium in liver. FEBS Lett. 1977 Jun 15;78(2):166–168. doi: 10.1016/0014-5793(77)80297-4. [DOI] [PubMed] [Google Scholar]
- Batra S. Studies on calcium uptake by myometrial microsomes with particular reference to the dependence on inorganic phosphate and oxalate. Acta Physiol Scand. 1978 Sep;104(1):68–73. doi: 10.1111/j.1748-1716.1978.tb06252.x. [DOI] [PubMed] [Google Scholar]
- Bygrave F. L. Properties of energy-dependent calcium transport by rat liver microsomal fraction as revealed by initial-rate measurements. Biochem J. 1978 Jan 15;170(1):87–91. doi: 10.1042/bj1700087. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bygrave F. L., Tranter C. J. The subcellular location, maturation and response to increased plasma glucagon of ruthenium red-insensitive calcium-ion transport in rat liver. Biochem J. 1978 Sep 15;174(3):1021–1030. doi: 10.1042/bj1741021. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Fleischer S., Kervina M. Subcellular fractionation of rat liver. Methods Enzymol. 1974;31:6–41. doi: 10.1016/0076-6879(74)31005-1. [DOI] [PubMed] [Google Scholar]
- LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
- Rasmussen H., Goodman D. B. Relationships between calcium and cyclic nucleotides in cell activation. Physiol Rev. 1977 Jul;57(3):421–509. doi: 10.1152/physrev.1977.57.3.421. [DOI] [PubMed] [Google Scholar]
- Reinhart P. H., Bygrave F. L. Glucagon stimulation of ruthenium red-insensitive calcium ion transport in developing rat liver. Biochem J. 1981 Feb 15;194(2):541–549. doi: 10.1042/bj1940541. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Taylor W. M., Bygrave F. L., Blackmore P. F., Exton J. H. Stable enhancement of ruthenium red-insensitive calcium transport in an endoplasmic reticulum-rich fraction following the exposure of isolated rat liver cells to glucagon. FEBS Lett. 1979 Aug 1;104(1):31–34. doi: 10.1016/0014-5793(79)81079-0. [DOI] [PubMed] [Google Scholar]
- Taylor W. M., Reinhart P., Hunt N. H., Bygrave F. L. Role of 3',5'-cyclic AMP in glucagon-induced stimulation of ruthenium red-insensitive calcium transport in an endoplasmic reticulum-rich fraction of rat liver. FEBS Lett. 1980 Mar 24;112(1):92–96. doi: 10.1016/0014-5793(80)80136-0. [DOI] [PubMed] [Google Scholar]
- Thorne R. F., Bygrave F. L. Energy-linked functions of tightly coupled mitochondria isolated from Ehrlich ascites tumor cells. Cancer Res. 1973 Nov;33(11):2562–2567. [PubMed] [Google Scholar]
- Tolbert N. E. Isolation of subcellular organelles of metabolism on isopycnic sucrose gradients. Methods Enzymol. 1974;31:734–746. doi: 10.1016/0076-6879(74)31077-4. [DOI] [PubMed] [Google Scholar]
- Waltenbaugh A. M., Friedmann N. Hormone sensitive calcium uptake by liver microsomes. Biochem Biophys Res Commun. 1978 May 30;82(2):603–608. doi: 10.1016/0006-291x(78)90917-8. [DOI] [PubMed] [Google Scholar]
- Wilson D. B. Cellular transport mechanisms. Annu Rev Biochem. 1978;47:933–965. doi: 10.1146/annurev.bi.47.070178.004441. [DOI] [PubMed] [Google Scholar]