Nature 312, 453 - 455 (29 November 1984); doi:10.1038/312453a0

Capacitance measurements reveal stepwise fusion events in degranulating mast cells

J. M. Fernandez, E. Neher & B. D. Gomperts^*

Department of Membrane Biophysics, Max-Planck-Institut für Biophysikalische Chemie, D-3400, Göttingen, FRG
^*Department of Experimental Pathology, University College London, University Street, London WC1E 6JJ, UK

Mast cells undergo an extensive and violent morphological transformation on stimulation¹. Here we describe the dynamics of fusion of the secretory granules in individual mast cells during exocytosis. The cell membrane capacitance (proportional to the cell surface area) was measured using the whole-cell patch-pipette technique^2,3, in which the intracellular space is dialysed with the solutions used to fill the patch pipette. Our results show that degranulation occurs spontaneously and reproducibly if the GTP analogue, GTP--S, and Mg-ATP are present in the pipette filling solution. Contrary to previous reports⁴⁻⁸, in these conditions Ca²⁺ (and/or Ca²⁺ buffers) is not required for degranulation. Although electrogenic Ca²⁺ entry was not detected before or during degranulation and membrane conductance remained low, the capacitance, and by implication the area of the membrane of degranulating cells, increased sigmoidally and stepwise. We conclude that stepwise increases of capacitance are due to the fusion of individual secretory granules with the plasma membrane, and that guanine nucleotide regulatory proteins are involved in the control of this process.

References

1.	Chandler, D. E. & Heuser, J. E. J. Cell Biol. 86, 666−674 (1980). | Article | PubMed | ISI | ChemPort |
2.	Neher, E. & Marty, A. Proc. natn. Acad. Sci. U.S.A. 79, 6712−6716 (1982). | ChemPort |
3.	Fernandez, J. M., Bezanilla, F. & Taylor, R. E. J. gen. Physiol. 79, 41−67 (1982). | Article | PubMed | ISI | ChemPort |
4.	Bennett, J. P., Cockcroft, S. & Gomperts, B. D. Nature 282, 851−853 (1979). | PubMed | ISI | ChemPort |
5.	Gomperts, B. D., Bennet, J. P. & Allan, D. Eur. J. Biochem. 117, 559−562 (1981). | PubMed | ISI | ChemPort |
6.	Bennett, J. P., Cockcroft, S. & Gomperts, B. D. J. Physiol., Lond. 317, 335−345 (1981). | PubMed | ISI | ChemPort |
7.	Gomperts, B. D., Baldwin, J. M. & Micklem, K. J. Biochem. J. 217, 737−745 (1983).
8.	White, J. R., Sha'afi, R. I., Ishizakam, K. & Ishizaka, T. Proc. natn. Acad. Sci. U.S.A. 81, 3978−3982 (1984). | ChemPort |
9.	Kanno, T., Cochrane, D. E. & Douglas, W. W. Can. J. Physiol. Pharmac. 51, 1001−1004 (1973). | ISI | ChemPort |
10.	Houslay, M. D. Trends biochem. Sci. 9, 39−40 (1984). | Article | ISI | ChemPort |
11.	Gomperts, B. D. Nature 306, 64−66 (1983). | PubMed | ISI | ChemPort |
12.	Hamill, O. P., Marty, A., Neher, E., Sakmann, B. & Sigworth, F. J. Pflügers Arch. ges. Physiol. 391, 85−100 (1981). | ChemPort |
13.	Marty, A. & Neher, E. in Single Channel Recording (eds Sakmann, B. & Neher, E.) 107−121 (Plenum, New York, 1983).
14.	Helander, H. F. & Bloom, G. J. Microsc. 100, 315−321 (1973). | ISI |
15.	Rohlich, P., Anderson, P. & Uvnas, B. J. Cell Biol. 51, 465−483 (1971). | Article | PubMed | ISI | ChemPort |
16.	Lawson, D., Raff, M. R., Fewtrell, C. M. S., Gomperts, B. D. & Gilula, N. B. J. Cell Biol. 77, 242−259 (1977). | Article |
17.	Cockcroft, S. & Gomperts, B. D. J. Physiol., Lond. 296, 229−243 (1979). | PubMed | ISI | ChemPort |