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. 1982 Jul 1;94(1):97–107. doi: 10.1083/jcb.94.1.97

Reevaluation of brush border motility: calcium induces core filament solation and microvillar vesiculation

DR Burgess, BE Prum
PMCID: PMC2112202  PMID: 6889606

Abstract

The report that microvillar cores of isolated, demembranated brush borders retract into the terminal web in the presence of Ca(++) and ATP has been widely cited as an example of Ca(++)-regulated nonmuscle cell motility. Because of recent findings that microvillar core actin filaments are cross-linked by villin which, in the presence of micromolar Ca(++), fragments actin filaments, we used the techniques of video enhanced differential interference contrast, immunofluorescence, and phase contrast microscopy and thin-section electron microscopy (EM) to reexamine the question of contraction of isolated intestinal cell brush borders. Analysis of video enhanced light microscopic images of Triton- demembranated brush borders treated with a buffered Ca(++) solution shows the cores disintegrating with the terminal web remaining intact; membranated brush borders show the microvilli to vesiculate with Ca(++). Using Ca(++)/EGTA buffers, it is found that micromolar free Ca(++) causes core filament dissolution in membranated or demembranated brush borders, Ca(++) causes microvillar core solation followed by complete vesiculation of the microvillar membrane. The lengths of microvilli cores and rootlets were measured in thin sections of membranated and demembranated controls, in Ca(++)-, Ca(++) + ATP-, and in ATP-treated brush borders. Results of these measurements show that Ca(++) alone causes the complete solation of the microvillar cores, yet the rootlets in the terminal web region remain of normal length. These results show that microvilli do not retract into the terminal web in response to Ca(++) and ATP but rather that the microvillar cores disintegrate. NBD-phallicidin localization of actin and fluorescent antibodies to myosin reveal a circumferential band of actin and myosin in mildly permeabilized cells in the region of the junctional complex. The presence of these contractile proteins in this region, where other studies have shown a circumferential band of thin filaments, is consistent with the hypothesis that brush borders may be motile through the circumferential constriction of this “contractile ring,” and is also consistent with the observations that ATP-treated brush borders become cup shaped as if there had been a circumferential constriction.

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Selected References

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

  1. Begg D. A., Rodewald R., Rebhun L. I. The visualization of actin filament polarity in thin sections. Evidence for the uniform polarity of membrane-associated filaments. J Cell Biol. 1978 Dec;79(3):846–852. doi: 10.1083/jcb.79.3.846. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Bretscher A., Weber K. Localization of actin and microfilament-associated proteins in the microvilli and terminal web of the intestinal brush border by immunofluorescence microscopy. J Cell Biol. 1978 Dec;79(3):839–845. doi: 10.1083/jcb.79.3.839. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Bretscher A., Weber K. Villin is a major protein of the microvillus cytoskeleton which binds both G and F actin in a calcium-dependent manner. Cell. 1980 Jul;20(3):839–847. doi: 10.1016/0092-8674(80)90330-x. [DOI] [PubMed] [Google Scholar]
  4. Craig S. W., Pardo J. V. alpha-Actinin localization in the junctional complex of intestinal epithelial cells. J Cell Biol. 1979 Jan;80(1):203–210. doi: 10.1083/jcb.80.1.203. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Craig S. W., Powell L. D. Regulation of actin polymerization by villin, a 95,000 dalton cytoskeletal component of intestinal brush borders. Cell. 1980 Dec;22(3):739–746. doi: 10.1016/0092-8674(80)90550-4. [DOI] [PubMed] [Google Scholar]
  6. Drenckhahn D., Gröschel-Stewart U. Localization of myosin, actin, and tropomyosin in rat intestinal epithelium: immunohistochemical studies at the light and electron microscope levels. J Cell Biol. 1980 Aug;86(2):475–482. doi: 10.1083/jcb.86.2.475. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Fujiwara K., Porter M. E., Pollard T. D. Alpha-actinin localization in the cleavage furrow during cytokinesis. J Cell Biol. 1978 Oct;79(1):268–275. doi: 10.1083/jcb.79.1.268. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Geiger B., Dutton A. H., Tokuyasu K. T., Singer S. J. Immunoelectron microscope studies of membrane-microfilament interactions: distributions of alpha-actinin, tropomyosin, and vinculin in intestinal epithelial brush border and chicken gizzard smooth muscle cells. J Cell Biol. 1981 Dec;91(3 Pt 1):614–628. doi: 10.1083/jcb.91.3.614. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Glenney J. R., Jr, Kaulfus P., Matsudaira P., Weber K. F-actin binding and bundling properties of fimbrin, a major cytoskeletal protein of microvillus core filaments. J Biol Chem. 1981 Sep 10;256(17):9283–9288. [PubMed] [Google Scholar]
  10. Glenney J. R., Jr, Weber K. Calmodulin-binding proteins of the microfilaments present in isolated brush borders and microvilli of intestinal epithelial cells. J Biol Chem. 1980 Nov 25;255(22):10551–10554. [PubMed] [Google Scholar]
  11. Herman I. M., Pollard T. D. Electron microscopic localization of cytoplasmic myosin with ferritin-labeled antibodies. J Cell Biol. 1981 Feb;88(2):346–351. doi: 10.1083/jcb.88.2.346. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Hirokawa N., Heuser J. E. Quick-freeze, deep-etch visualization of the cytoskeleton beneath surface differentiations of intestinal epithelial cells. J Cell Biol. 1981 Nov;91(2 Pt 1):399–409. doi: 10.1083/jcb.91.2.399. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Howe C. L., Mooseker M. S., Graves T. A. Brush-border calmodulin. A major component of the isolated microvillus core. J Cell Biol. 1980 Jun;85(3):916–923. doi: 10.1083/jcb.85.3.916. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Hull B. E., Staehelin L. A. The terminal web. A reevaluation of its structure and function. J Cell Biol. 1979 Apr;81(1):67–82. doi: 10.1083/jcb.81.1.67. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Matsudaira P. T., Burgess D. R. Identification and organization of the components in the isolated microvillus cytoskeleton. J Cell Biol. 1979 Dec;83(3):667–673. doi: 10.1083/jcb.83.3.667. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Matsudaira P. T., Burgess D. R. Organization of the cross-filaments in intestinal microvilli. J Cell Biol. 1982 Mar;92(3):657–664. doi: 10.1083/jcb.92.3.657. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Mooseker M. S. Brush border motility. Microvillar contraction in triton-treated brush borders isolated from intestinal epithelium. J Cell Biol. 1976 Nov;71(2):417–433. doi: 10.1083/jcb.71.2.417. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Mooseker M. S., Graves T. A., Wharton K. A., Falco N., Howe C. L. Regulation of microvillus structure: calcium-dependent solation and cross-linking of actin filaments in the microvilli of intestinal epithelial cells. J Cell Biol. 1980 Dec;87(3 Pt 1):809–822. doi: 10.1083/jcb.87.3.809. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Mooseker M. S., Pollard T. D., Fujiwara K. Characterization and localization of myosin in the brush border of intestinal epithelial cells. J Cell Biol. 1978 Nov;79(2 Pt 1):444–453. doi: 10.1083/jcb.79.2.444. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Mooseker M. S., Tilney L. G. Organization of an actin filament-membrane complex. Filament polarity and membrane attachment in the microvilli of intestinal epithelial cells. J Cell Biol. 1975 Dec;67(3):725–743. doi: 10.1083/jcb.67.3.725. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Owaribe K., Kodama R., Eguchi G. Demonstration of contractility of circumferential actin bundles and its morphogenetic significance in pigmented epithelium in vitro and in vivo. J Cell Biol. 1981 Aug;90(2):507–514. doi: 10.1083/jcb.90.2.507. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Rodewald R., Newman S. B., Karnovsky M. J. Contraction of isolated brush borders from the intestinal epithelium. J Cell Biol. 1976 Sep;70(3):541–554. doi: 10.1083/jcb.70.3.541. [DOI] [PMC free article] [PubMed] [Google Scholar]

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