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. 1998 Jan;74(1):290–296. doi: 10.1016/S0006-3495(98)77786-0

Changes in luminal pH caused by calcium release in sarcoplasmic reticulum vesicles.

F Kamp 1, P Donoso 1, C Hidalgo 1
PMCID: PMC1299381  PMID: 9449329

Abstract

Fast (milliseconds) Ca2+ release from sarcoplasmic reticulum is an essential step in muscle contraction. To electrically compensate the charge deficit generated by calcium release, concomitant fluxes of other ions are required. In this study we investigated the possible participation of protons as counterions during calcium release. Triad-enriched sarcoplasmic reticulum vesicles, isolated from rabbit fast skeletal muscle, were passively loaded with 1 mM CaCl2 and release was induced at pCa = 5.0 and pH = 7.0 in a stopped-flow fluorimeter. Accompanying changes in vesicular lumen pH were measured with a trapped fluorescent pH indicator (pyranin). Significant acidification (approximately 0.2 pH units) of the lumen occurred within the same time scale (t(1/2) = 0.75 s) as calcium release. Enhancing calcium release with ATP or the ATP analog 5'-adenylylimidodiphosphate (AMPPNP) produced >20-fold faster acidification rates. In contrast, when calcium release induced with calcium with or without AMPPNP was blocked by Mg2+, no acidification of the lumen was observed. In all cases, rate constants of luminal acidification corresponded with reported values of calcium release rate constants. We conclude that proton fluxes account for part (5-10%) of the necessary charge compensation during calcium release. The possible relevance of these findings to the physiology of muscle cells is discussed.

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Selected References

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  1. Decker B., Sender S., Gros G. Membrane-associated carbonic anhydrase IV in skeletal muscle: subcellular localization. Histochem Cell Biol. 1996 Oct;106(4):405–411. doi: 10.1007/BF02473299. [DOI] [PubMed] [Google Scholar]
  2. Donoso P., Beltrán M., Hidalgo C. Luminal pH regulated calcium release kinetics in sarcoplasmic reticulum vesicles. Biochemistry. 1996 Oct 15;35(41):13419–13425. doi: 10.1021/bi9616209. [DOI] [PubMed] [Google Scholar]
  3. Donoso P., Hidalgo C. pH-sensitive calcium release in triads from frog skeletal muscle. Rapid filtration studies. J Biol Chem. 1993 Dec 5;268(34):25432–25438. [PubMed] [Google Scholar]
  4. Donoso P., Prieto H., Hidalgo C. Luminal calcium regulates calcium release in triads isolated from frog and rabbit skeletal muscle. Biophys J. 1995 Feb;68(2):507–515. doi: 10.1016/S0006-3495(95)80212-2. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Dulhunty A. F., Junankar P. R., Eager K. R., Ahern G. P., Laver D. R. Ion channels in the sarcoplasmic reticulum of striated muscle. Acta Physiol Scand. 1996 Mar;156(3):375–385. doi: 10.1046/j.1365-201X.1996.193000.x. [DOI] [PubMed] [Google Scholar]
  6. Fink R. H., Veigel C. Calcium uptake and release modulated by counter-ion conductances in the sarcoplasmic reticulum of skeletal muscle. Acta Physiol Scand. 1996 Mar;156(3):387–396. doi: 10.1046/j.1365-201X.1996.212000.x. [DOI] [PubMed] [Google Scholar]
  7. Garcia A. M., Miller C. Channel-mediated monovalent cation fluxes in isolated sarcoplasmic reticulum vesicles. J Gen Physiol. 1984 Jun;83(6):819–839. doi: 10.1085/jgp.83.6.819. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Hidalgo C., Donoso P., Rodriguez P. H. Protons induce calsequestrin conformational changes. Biophys J. 1996 Oct;71(4):2130–2137. doi: 10.1016/S0006-3495(96)79413-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Hidalgo C., Jorquera J., Tapia V., Donoso P. Triads and transverse tubules isolated from skeletal muscle contain high levels of inositol 1,4,5-trisphosphate. J Biol Chem. 1993 Jul 15;268(20):15111–15117. [PubMed] [Google Scholar]
  10. Kamp F., Hamilton J. A. pH gradients across phospholipid membranes caused by fast flip-flop of un-ionized fatty acids. Proc Natl Acad Sci U S A. 1992 Dec 1;89(23):11367–11370. doi: 10.1073/pnas.89.23.11367. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Kamp F., Zakim D., Zhang F., Noy N., Hamilton J. A. Fatty acid flip-flop in phospholipid bilayers is extremely fast. Biochemistry. 1995 Sep 19;34(37):11928–11937. doi: 10.1021/bi00037a034. [DOI] [PubMed] [Google Scholar]
  12. Kourie J. I., Laver D. R., Ahern G. P., Dulhunty A. F. A calcium-activated chloride channel in sarcoplasmic reticulum vesicles from rabbit skeletal muscle. Am J Physiol. 1996 Jun;270(6 Pt 1):C1675–C1686. doi: 10.1152/ajpcell.1996.270.6.C1675. [DOI] [PubMed] [Google Scholar]
  13. Meissner G. Ryanodine receptor/Ca2+ release channels and their regulation by endogenous effectors. Annu Rev Physiol. 1994;56:485–508. doi: 10.1146/annurev.ph.56.030194.002413. [DOI] [PubMed] [Google Scholar]
  14. Meissner G., Young R. C. Proton permeability of sarcoplasmic reticulum vesicles. J Biol Chem. 1980 Jul 25;255(14):6814–6819. [PubMed] [Google Scholar]
  15. Melzer W., Herrmann-Frank A., Lüttgau H. C. The role of Ca2+ ions in excitation-contraction coupling of skeletal muscle fibres. Biochim Biophys Acta. 1995 May 8;1241(1):59–116. doi: 10.1016/0304-4157(94)00014-5. [DOI] [PubMed] [Google Scholar]
  16. Miller C. Voltage-gated cation conductance channel from fragmented sarcoplasmic reticulum: steady-state electrical properties. J Membr Biol. 1978 Apr 20;40(1):1–23. doi: 10.1007/BF01909736. [DOI] [PubMed] [Google Scholar]
  17. Mintz E., Guillain F. Ca2+ transport by the sarcoplasmic reticulum ATPase. Biochim Biophys Acta. 1997 Jan 16;1318(1-2):52–70. doi: 10.1016/s0005-2728(96)00132-6. [DOI] [PubMed] [Google Scholar]
  18. Mitchell P., Moyle J. Acid-base titration across the membrane system of rat-liver mitochondria. Catalysis by uncouplers. Biochem J. 1967 Aug;104(2):588–600. doi: 10.1042/bj1040588. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Moutin M. J., Dupont Y. Rapid filtration studies of Ca2+-induced Ca2+ release from skeletal sarcoplasmic reticulum. Role of monovalent ions. J Biol Chem. 1988 Mar 25;263(9):4228–4235. [PubMed] [Google Scholar]
  20. Nunogaki K., Kasai M. Determination of the rate of rapid pH equilibration across isolated sarcoplasmic reticulum membranes. Biochem Biophys Res Commun. 1986 Nov 14;140(3):934–940. doi: 10.1016/0006-291x(86)90725-4. [DOI] [PubMed] [Google Scholar]
  21. Pape P. C., Konishi M., Hollingworth S., Baylor S. M. Perturbation of sarcoplasmic reticulum calcium release and phenol red absorbance transients by large concentrations of fura-2 injected into frog skeletal muscle fibers. J Gen Physiol. 1990 Sep;96(3):493–516. doi: 10.1085/jgp.96.3.493. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Shoshan-Barmatz V., Hadad N., Feng W., Shafir I., Orr I., Varsanyi M., Heilmeyer L. M. VDAC/porin is present in sarcoplasmic reticulum from skeletal muscle. FEBS Lett. 1996 May 20;386(2-3):205–210. doi: 10.1016/0014-5793(96)00442-5. [DOI] [PubMed] [Google Scholar]
  23. Somlyo A. V., Gonzalez-Serratos H. G., Shuman H., McClellan G., Somlyo A. P. Calcium release and ionic changes in the sarcoplasmic reticulum of tetanized muscle: an electron-probe study. J Cell Biol. 1981 Sep;90(3):577–594. doi: 10.1083/jcb.90.3.577. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Tanifuji M., Sokabe M., Kasai M. An anion channel of sarcoplasmic reticulum incorporated into planar lipid bilayers: single-channel behavior and conductance properties. J Membr Biol. 1987;99(2):103–111. doi: 10.1007/BF01871230. [DOI] [PubMed] [Google Scholar]
  25. Westerblad H., Lee J. A., Lännergren J., Allen D. G. Cellular mechanisms of fatigue in skeletal muscle. Am J Physiol. 1991 Aug;261(2 Pt 1):C195–C209. doi: 10.1152/ajpcell.1991.261.2.C195. [DOI] [PubMed] [Google Scholar]

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