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. 1985 Aug;82(15):5030–5034. doi: 10.1073/pnas.82.15.5030

The cytoplasmic matrix: its volume and surface area and the diffusion of molecules through it.

N D Gershon, K R Porter, B L Trus
PMCID: PMC390492  PMID: 3860842

Abstract

In this work we look into the problem of why proteins, unlike small molecules, diffuse in the cytoplasm much more slowly than in aqueous solutions. In order to examine whether the cytoplasmic matrix could, by simple obstruction, retard protein diffusion to such an extent, we developed a method to measure semiquantitatively the fractional volume occupied by the cytoplasmic matrix (which includes the microfilaments, intermediate filaments, microtubules, and the microtrabeculae of the cytoplasmic matrix). This method yielded values in the range of only 16-21%. Thus, a more elaborate model is suggested in which the diffusing proteins bind and dissociate constantly from the surfaces in the cytoplasmic matrix. From this model, the diffusion coefficients and the measured values of the fractional volumes, we calculated the corresponding binding constants. These values indicate that most of the diffusing proteins are bound to the matrix at any given time, in spite of the possibility that they may bind and dissociate very rapidly. In addition, from our measurements, we estimate the surface area of structures within the cytoplasmic matrix to be in the range of 69,000-91,000 micron 2 per cell.

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Selected References

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

  1. Buckley I. K. Three dimensional fine structure of cultured cells: possible implications for subcellular motility. Tissue Cell. 1975;7(1):51–72. doi: 10.1016/s0040-8166(75)80007-3. [DOI] [PubMed] [Google Scholar]
  2. Clegg J. S. Intracellular water and the cytomatrix: some methods of study and current views. J Cell Biol. 1984 Jul;99(1 Pt 2):167s–171s. doi: 10.1083/jcb.99.1.167s. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Edidin M., Zagyansky Y., Lardner T. J. Measurement of membrane protein lateral diffusion in single cells. Science. 1976 Feb 6;191(4226):466–468. doi: 10.1126/science.1246629. [DOI] [PubMed] [Google Scholar]
  4. Elson E. L., Reidler J. A. Analysis of cell surface interactions by measurements of lateral mobility. J Supramol Struct. 1979;12(4):481–489. doi: 10.1002/jss.400120408. [DOI] [PubMed] [Google Scholar]
  5. Jacobson K., Wojcieszyn J. The translational mobility of substances within the cytoplasmic matrix. Proc Natl Acad Sci U S A. 1984 Nov;81(21):6747–6751. doi: 10.1073/pnas.81.21.6747. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Kempner E. S., Miller J. H. The molecular biology of Euglena gracilis. V. Enzyme localization. Exp Cell Res. 1968 Jul;51(1):150–156. doi: 10.1016/0014-4827(68)90165-1. [DOI] [PubMed] [Google Scholar]
  7. Kreis T. E., Geiger B., Schlessinger J. Mobility of microinjected rhodamine actin within living chicken gizzard cells determined by fluorescence photobleaching recovery. Cell. 1982 Jul;29(3):835–845. doi: 10.1016/0092-8674(82)90445-7. [DOI] [PubMed] [Google Scholar]
  8. Mastro A. M., Babich M. A., Taylor W. D., Keith A. D. Diffusion of a small molecule in the cytoplasm of mammalian cells. Proc Natl Acad Sci U S A. 1984 Jun;81(11):3414–3418. doi: 10.1073/pnas.81.11.3414. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Mastro A. M., Keith A. D. Diffusion in the aqueous compartment. J Cell Biol. 1984 Jul;99(1 Pt 2):180s–187s. doi: 10.1083/jcb.99.1.180s. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Peters R., Peters J., Tews K. H., Bähr W. A microfluorimetric study of translational diffusion in erythrocyte membranes. Biochim Biophys Acta. 1974 Nov 15;367(3):282–294. doi: 10.1016/0005-2736(74)90085-6. [DOI] [PubMed] [Google Scholar]
  11. Poo M., Cone R. A. Lateral diffusion of rhodopsin in the photoreceptor membrane. Nature. 1974 Feb 15;247(5441):438–441. doi: 10.1038/247438a0. [DOI] [PubMed] [Google Scholar]
  12. Porter K. R., Anderson K. L. The structure of the cytoplasmic matrix preserved by freeze-drying and freeze-substitution. Eur J Cell Biol. 1982 Nov;29(1):83–96. [PubMed] [Google Scholar]
  13. Porter K. R., Tucker J. B. The ground substance of the living cell. Sci Am. 1981 Mar;244(3):56–67. doi: 10.1038/scientificamerican0381-56. [DOI] [PubMed] [Google Scholar]
  14. Schlessinger J., Koppel D. E., Axelrod D., Jacobson K., Webb W. W., Elson E. L. Lateral transport on cell membranes: mobility of concanavalin A receptors on myoblasts. Proc Natl Acad Sci U S A. 1976 Jul;73(7):2409–2413. doi: 10.1073/pnas.73.7.2409. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Wang Y. L., Lanni F., McNeil P. L., Ware B. R., Taylor D. L. Mobility of cytoplasmic and membrane-associated actin in living cells. Proc Natl Acad Sci U S A. 1982 Aug;79(15):4660–4664. doi: 10.1073/pnas.79.15.4660. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Wojcieszyn J. W., Schlegel R. A., Wu E. S., Jacobson K. A. Diffusion of injected macromolecules within the cytoplasm of living cells. Proc Natl Acad Sci U S A. 1981 Jul;78(7):4407–4410. doi: 10.1073/pnas.78.7.4407. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Wolosewick J. J., Porter K. R. Microtrabecular lattice of the cytoplasmic ground substance. Artifact or reality. J Cell Biol. 1979 Jul;82(1):114–139. doi: 10.1083/jcb.82.1.114. [DOI] [PMC free article] [PubMed] [Google Scholar]

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