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. 1990 Oct;87(20):7804–7808. doi: 10.1073/pnas.87.20.7804

Tension in secretory granule membranes causes extensive membrane transfer through the exocytotic fusion pore.

J R Monck 1, G Alvarez de Toledo 1, J M Fernandez 1
PMCID: PMC54838  PMID: 2235997

Abstract

For fusion to occur the repulsive forces between two interacting phospholipid bilayers must be reduced. In model systems, this can be achieved by increasing the surface tension of at least one of the membranes. However, there has so far been no evidence that the secretory granule membrane is under tension. We have been studying exocytosis by using the patch-clamp technique to measure the surface area of the plasma membrane of degranulating mast cells. When a secretory granule fuses with the plasma membrane there is a step increase in the cell surface area. Some fusion events are reversible, in which case we have found that the backstep is larger than the initial step, indicating that there is a net decrease in the area of the plasma membrane. The decrease has the following properties: (i) the magnitude is strongly dependent on the lifetime of the fusion event and can be extensive, representing as much as 40% of the initial granule surface area; (ii) the rate of decrease is independent of granule size; and (iii) the decrease is not dependent on swelling of the secretory granule matrix. We conclude that the granule membrane is under tension and that this tension causes a net transfer of membrane from the plasma membrane to the secretory granule, while they are connected by the fusion pore. The high membrane tension in the secretory granule may be the critical stress necessary for bringing about exocytotic fusion.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Ahkong Q. F., Lucy J. A. Osmotic forces in artificially induced cell fusion. Biochim Biophys Acta. 1986 Jun 13;858(1):206–216. doi: 10.1016/0005-2736(86)90308-1. [DOI] [PubMed] [Google Scholar]
  2. Almers W. Exocytosis. Annu Rev Physiol. 1990;52:607–624. doi: 10.1146/annurev.ph.52.030190.003135. [DOI] [PubMed] [Google Scholar]
  3. Almers W., Neher E. Gradual and stepwise changes in the membrane capacitance of rat peritoneal mast cells. J Physiol. 1987 May;386:205–217. doi: 10.1113/jphysiol.1987.sp016530. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Alvarez de Toledo G., Fernandez J. M. Patch-clamp measurements reveal multimodal distribution of granule sizes in rat mast cells. J Cell Biol. 1990 Apr;110(4):1033–1039. doi: 10.1083/jcb.110.4.1033. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Breckenridge L. J., Almers W. Currents through the fusion pore that forms during exocytosis of a secretory vesicle. 1987 Aug 27-Sep 2Nature. 328(6133):814–817. doi: 10.1038/328814a0. [DOI] [PubMed] [Google Scholar]
  6. Breckenridge L. J., Almers W. Final steps in exocytosis observed in a cell with giant secretory granules. Proc Natl Acad Sci U S A. 1987 Apr;84(7):1945–1949. doi: 10.1073/pnas.84.7.1945. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Burgoyne R. D., Cheek T. R. Cytoskeleton: role of fodrin in secretion. Nature. 1987 Apr 2;326(6112):448–448. doi: 10.1038/326448a0. [DOI] [PubMed] [Google Scholar]
  8. Chandler D. E., Heuser J. E. Arrest of membrane fusion events in mast cells by quick-freezing. J Cell Biol. 1980 Aug;86(2):666–674. doi: 10.1083/jcb.86.2.666. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Chandler D. E., Whitaker M., Zimmerberg J. High molecular weight polymers block cortical granule exocytosis in sea urchin eggs at the level of granule matrix disassembly. J Cell Biol. 1989 Sep;109(3):1269–1278. doi: 10.1083/jcb.109.3.1269. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Chaudhury M. K., Ohki S. Correlation between membrane expansion and temperature-induced membrane fusion. Biochim Biophys Acta. 1981 Apr 6;642(2):365–374. doi: 10.1016/0005-2736(81)90452-1. [DOI] [PubMed] [Google Scholar]
  11. Cohen F. S., Akabas M. H., Finkelstein A. Osmotic swelling of phospholipid vesicles causes them to fuse with a planar phospholipid bilayer membrane. Science. 1982 Jul 30;217(4558):458–460. doi: 10.1126/science.6283637. [DOI] [PubMed] [Google Scholar]
  12. Cohen F. S., Niles W. D., Akabas M. H. Fusion of phospholipid vesicles with a planar membrane depends on the membrane permeability of the solute used to create the osmotic pressure. J Gen Physiol. 1989 Feb;93(2):201–210. doi: 10.1085/jgp.93.2.201. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Evans E. A., Waugh R., Melnik L. Elastic area compressibility modulus of red cell membrane. Biophys J. 1976 Jun;16(6):585–595. doi: 10.1016/S0006-3495(76)85713-X. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Fernandez J. M., Neher E., Gomperts B. D. Capacitance measurements reveal stepwise fusion events in degranulating mast cells. 1984 Nov 29-Dec 5Nature. 312(5993):453–455. doi: 10.1038/312453a0. [DOI] [PubMed] [Google Scholar]
  15. Fidler N., Fernandez J. M. Phase tracking: an improved phase detection technique for cell membrane capacitance measurements. Biophys J. 1989 Dec;56(6):1153–1162. doi: 10.1016/S0006-3495(89)82762-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Finkelstein A., Zimmerberg J., Cohen F. S. Osmotic swelling of vesicles: its role in the fusion of vesicles with planar phospholipid bilayer membranes and its possible role in exocytosis. Annu Rev Physiol. 1986;48:163–174. doi: 10.1146/annurev.ph.48.030186.001115. [DOI] [PubMed] [Google Scholar]
  17. Gomperts B. D., Tatham P. E. GTP-binding proteins in the control of exocytosis. Cold Spring Harb Symp Quant Biol. 1988;53(Pt 2):983–992. doi: 10.1101/sqb.1988.053.01.113. [DOI] [PubMed] [Google Scholar]
  18. Hall J. E. Voltage-dependent lipid flip-flop induced by alamethicin. Biophys J. 1981 Mar;33(3):373–381. doi: 10.1016/S0006-3495(81)84901-6. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Helm C. A., Israelachvili J. N., McGuiggan P. M. Molecular mechanisms and forces involved in the adhesion and fusion of amphiphilic bilayers. Science. 1989 Nov 17;246(4932):919–922. doi: 10.1126/science.2814514. [DOI] [PubMed] [Google Scholar]
  20. Holz R. W. The role of osmotic forces in exocytosis from adrenal chromaffin cells. Annu Rev Physiol. 1986;48:175–189. doi: 10.1146/annurev.ph.48.030186.001135. [DOI] [PubMed] [Google Scholar]
  21. Israelachvili J. N., McGuiggan P. M. Forces between surfaces in liquids. Science. 1988 Aug 12;241(4867):795–800. doi: 10.1126/science.241.4867.795. [DOI] [PubMed] [Google Scholar]
  22. Joshi C., Fernandez J. M. Capacitance measurements. An analysis of the phase detector technique used to study exocytosis and endocytosis. Biophys J. 1988 Jun;53(6):885–892. doi: 10.1016/S0006-3495(88)83169-2. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Lucy J. A., Ahkong Q. F. An osmotic model for the fusion of biological membranes. FEBS Lett. 1986 Apr 7;199(1):1–11. doi: 10.1016/0014-5793(86)81213-3. [DOI] [PubMed] [Google Scholar]
  24. Merkle C. J., Chandler D. E. Hyperosmolality inhibits exocytosis in sea urchin eggs by formation of a granule-free zone and arrest of pore widening. J Membr Biol. 1989 Dec;112(3):223–232. doi: 10.1007/BF01870953. [DOI] [PubMed] [Google Scholar]
  25. Needham D., Hochmuth R. M. Electro-mechanical permeabilization of lipid vesicles. Role of membrane tension and compressibility. Biophys J. 1989 May;55(5):1001–1009. doi: 10.1016/S0006-3495(89)82898-X. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Niles W. D., Cohen F. S., Finkelstein A. Hydrostatic pressures developed by osmotically swelling vesicles bound to planar membranes. J Gen Physiol. 1989 Feb;93(2):211–244. doi: 10.1085/jgp.93.2.211. [DOI] [PMC free article] [PubMed] [Google Scholar]
  27. Ohki S. A mechanism of divalent ion-induced phosphatidylserine membrane fusion. Biochim Biophys Acta. 1982 Jul 14;689(1):1–11. doi: 10.1016/0005-2736(82)90182-1. [DOI] [PubMed] [Google Scholar]
  28. Ohki S. Effects of divalent cations, temperature, osmotic pressure gradient, and vesicle curvature on phosphatidylserine vesicle fusion. J Membr Biol. 1984;77(3):265–275. doi: 10.1007/BF01870574. [DOI] [PubMed] [Google Scholar]
  29. Penner R., Neher E. The role of calcium in stimulus-secretion coupling in excitable and non-excitable cells. J Exp Biol. 1988 Sep;139:329–345. doi: 10.1242/jeb.139.1.329. [DOI] [PubMed] [Google Scholar]
  30. Pollard H. B., Burns A. L., Rojas E. A molecular basis for synexin-driven, calcium-dependent membrane fusion. J Exp Biol. 1988 Sep;139:267–286. doi: 10.1242/jeb.139.1.267. [DOI] [PubMed] [Google Scholar]
  31. Pollard H. B., Rojas E., Burns A. L. Synexin and chromaffin granule membrane fusion. A novel "hydrophobic bridge" hypothesis for the driving and directing of the fusion process. Ann N Y Acad Sci. 1987;493:524–541. doi: 10.1111/j.1749-6632.1987.tb27238.x. [DOI] [PubMed] [Google Scholar]
  32. Spruce A. E., Breckenridge L. J., Lee A. K., Almers W. Properties of the fusion pore that forms during exocytosis of a mast cell secretory vesicle. Neuron. 1990 May;4(5):643–654. doi: 10.1016/0896-6273(90)90192-i. [DOI] [PubMed] [Google Scholar]
  33. Whitaker M., Zimmerberg J. Inhibition of secretory granule discharge during exocytosis in sea urchin eggs by polymer solutions. J Physiol. 1987 Aug;389:527–539. doi: 10.1113/jphysiol.1987.sp016670. [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Woodbury D. J., Hall J. E. Role of channels in the fusion of vesicles with a planar bilayer. Biophys J. 1988 Dec;54(6):1053–1063. doi: 10.1016/S0006-3495(88)83042-X. [DOI] [PMC free article] [PubMed] [Google Scholar]
  35. Zimmerberg J., Curran M., Cohen F. S., Brodwick M. Simultaneous electrical and optical measurements show that membrane fusion precedes secretory granule swelling during exocytosis of beige mouse mast cells. Proc Natl Acad Sci U S A. 1987 Mar;84(6):1585–1589. doi: 10.1073/pnas.84.6.1585. [DOI] [PMC free article] [PubMed] [Google Scholar]

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