Search tips
Search criteria 


Logo of jcellbiolHomeEditorsContactInstructions for Authors
J Cell Biol. 1990 December 1; 111(6): 2463–2473.
PMCID: PMC2116423

The cytoskeletal and contractile apparatus of smooth muscle: contraction bands and segmentation of the contractile elements


Confocal laser scanning microscopy of isolated and antibody-labeled avian gizzard smooth muscle cells has revealed the global organization of the contractile and cytoskeletal elements. The cytoskeleton, marked by antibodies to desmin and filamin is composed of a mainly longitudinal, meandering and branched system of fibrils that contrasts with the plait-like, interdigitating arrangement of linear fibrils of the contractile apparatus, labeled with antibodies to myosin and tropomyosin. Although desmin and filamin were colocalized in the body of the cell, filamin antibodies labeled additionally the vinculin- containing surface plaques. In confocal optical sections the contractile fibrils showed a continuous label for myosin for at least 5 microns along their length: there was no obvious or regular interruption of label as might be expected for registered myosin filaments. The cytoplasmic dense bodies, labeled with antibodies to alpha-actinin exhibited a regular, diagonal arrangement in both extended cells and in cells shortened in solution to one-fifth of their extended length: after the same shortening, the fibrils of the cytoskeleton that showed colocalization with the dense bodies in extended cells became crumpled and disordered. It is concluded that the dense bodies serve as coupling elements between the cytoskeletal and contractile systems. After extraction with Triton X-100, isolated cells bound so firmly to a glass substrate that they were unable to shorten as a whole when exposed to exogenous Mg ATP. Instead, they contracted internally, producing integral of 10 regularly spaced contraction nodes along their length. On the basis of differences of actin distribution two types of nodes could be distinguished: actin-positive nodes, in which actin straddled the node, and actin-negative nodes, characterized by an actin-free center flanked by actin fringes of 4.5 microns minimum length on either side. Myosin was concentrated in the center of the node in both cases. The differences in node morphology could be correlated with different degrees of coupling of the contractile with the cytoskeletal elements, effected by a preparation-dependent variability of proteolysis of the cells. The nodes were shown to be closely related to the supercontracted cell fragments shown in the accompanying paper (Small et al., 1990) and furnished further evidence for long actin filaments in smooth muscle. Further, the segmentation of the contractile elements pointed to a hierarchial organization of the myofilaments governed by as yet undetected elements.

Full Text

The Full Text of this article is available as a PDF (5.4M).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Ashton FT, Somlyo AV, Somlyo AP. The contractile apparatus of vascular smooth muscle: intermediate high voltage stereo electron microscopy. J Mol Biol. 1975 Oct 15;98(1):17–29. [PubMed]
  • Bagby R. Toward a comprehensive three-dimensional model of the contractile system of vertebrate smooth muscle cells. Int Rev Cytol. 1986;105:67–128. [PubMed]
  • Bennett JP, Cross RA, Kendrick-Jones J, Weeds AG. Spatial pattern of myosin phosphorylation in contracting smooth muscle cells: evidence for contractile zones. J Cell Biol. 1988 Dec;107(6 Pt 2):2623–2629. [PMC free article] [PubMed]
  • Bond M, Somlyo AV. Dense bodies and actin polarity in vertebrate smooth muscle. J Cell Biol. 1982 Nov;95(2 Pt 1):403–413. [PMC free article] [PubMed]
  • Cooke P. Organization of contractile fibers in smooth muscle. Cell Muscle Motil. 1983;3:57–77. [PubMed]
  • Draeger A, Stelzer EH, Herzog M, Small JV. Unique geometry of actin-membrane anchorage sites in avian gizzard smooth muscle cells. J Cell Sci. 1989 Dec;94(Pt 4):703–711. [PubMed]
  • Drenckhahn D, Beckerle M, Burridge K, Otto J. Identification and subcellular location of talin in various cell types and tissues by means of [125I]vinculin overlay, immunoblotting and immunocytochemistry. Eur J Cell Biol. 1988 Aug;46(3):513–522. [PubMed]
  • Fay FS, Fujiwara K, Rees DD, Fogarty KE. Distribution of alpha-actinin in single isolated smooth muscle cells. J Cell Biol. 1983 Mar;96(3):783–795. [PMC free article] [PubMed]
  • Fürst DO, Osborn M, Nave R, Weber K. The organization of titin filaments in the half-sarcomere revealed by monoclonal antibodies in immunoelectron microscopy: a map of ten nonrepetitive epitopes starting at the Z line extends close to the M line. J Cell Biol. 1988 May;106(5):1563–1572. [PMC free article] [PubMed]
  • Geiger B, Dutton AH, Tokuyasu KT, Singer SJ. 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. [PMC free article] [PubMed]
  • Giloh H, Sedat JW. Fluorescence microscopy: reduced photobleaching of rhodamine and fluorescein protein conjugates by n-propyl gallate. Science. 1982 Sep 24;217(4566):1252–1255. [PubMed]
  • Kargacin GJ, Cooke PH, Abramson SB, Fay FS. Periodic organization of the contractile apparatus in smooth muscle revealed by the motion of dense bodies in single cells. J Cell Biol. 1989 Apr;108(4):1465–1475. [PMC free article] [PubMed]
  • Maruyama K. Connectin, an elastic filamentous protein of striated muscle. Int Rev Cytol. 1986;104:81–114. [PubMed]
  • Nave R, Fürst DO, Weber K. Visualization of the polarity of isolated titin molecules: a single globular head on a long thin rod as the M band anchoring domain? J Cell Biol. 1989 Nov;109(5):2177–2187. [PMC free article] [PubMed]
  • Pavalko FM, Otey CA, Burridge K. Identification of a filamin isoform enriched at the ends of stress fibers in chicken embryo fibroblasts. J Cell Sci. 1989 Sep;94(Pt 1):109–118. [PubMed]
  • PEASE DC, MOLINARI S. Electron microscopy of muscular arteries; pial vessels of43 the cat and monkey. J Ultrastruct Res. 1960 Jun;3:447–468. [PubMed]
  • Small JV. Studies on isolated smooth muscle cells: The contractile apparatus. J Cell Sci. 1977 Apr;24:327–349. [PubMed]
  • Small JV. Geometry of actin-membrane attachments in the smooth muscle cell: the localisations of vinculin and alpha-actinin. EMBO J. 1985 Jan;4(1):45–49. [PubMed]
  • Small JV, Fürst DO, De Mey J. Localization of filamin in smooth muscle. J Cell Biol. 1986 Jan;102(1):210–220. [PMC free article] [PubMed]
  • Small JV, Herzog M, Barth M, Draeger A. Supercontracted state of vertebrate smooth muscle cell fragments reveals myofilament lengths. J Cell Biol. 1990 Dec;111(6 Pt 1):2451–2461. [PMC free article] [PubMed]
  • Stromer MH, Bendayan M. Arrangement of desmin intermediate filaments in smooth muscle cells as shown by high-resolution immunocytochemistry. Cell Motil Cytoskeleton. 1988;11(2):117–125. [PubMed]
  • Volberg T, Sabanay H, Geiger B. Spatial and temporal relationships between vinculin and talin in the developing chicken gizzard smooth muscle. Differentiation. 1986;32(1):34–43. [PubMed]
  • Wang K. Sarcomere-associated cytoskeletal lattices in striated muscle. Review and hypothesis. Cell Muscle Motil. 1985;6:315–369. [PubMed]
  • White JG, Amos WB, Fordham M. An evaluation of confocal versus conventional imaging of biological structures by fluorescence light microscopy. J Cell Biol. 1987 Jul;105(1):41–48. [PMC free article] [PubMed]

Articles from The Journal of Cell Biology are provided here courtesy of The Rockefeller University Press