A Study of the Mechanism of Contraction in Vertebrate Smooth Muscle

Shoenberg, Catherine F.; Needham, Dorothy M.

doi:10.1111/j.1469-185x.1976.tb01120.x

Cited by 60 publications

(24 citation statements)

References 168 publications

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“…The oblique arrangement offered a convenient way for contractile filaments to circumvent the relatively large and centrally located nucleus (Bagby, 1983). A criticism can be raised against all of the models mentioned above that there is considerable evidence against angled filament alignment in intact smooth muscle bundles from the present study and from other early studies (Shoenberg and Needham, 1976;Gabella, 1977;McGuffee et al, 1979). The findings of the present study also suggest that most contractile filaments do not circumvent the nucleus.…”

Section: Discussioncontrasting

confidence: 73%

Contractile filament architecture and force transmission in swine airway smooth muscle

Kuo

Seow

2004

Journal of Cell Science

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It is well known that the cyclic interaction of myosin cross bridges with actin filaments is responsible for force and shortening generation in smooth muscle. The intracellular organization of contractile filaments, however, is still poorly understood. Here, we show electron microscopic and functional evidence that contractile filaments in airway smooth muscle lie parallel to the longitudinal axis of the cell bundle, in contrast to the obliquely arranged filaments depicted in conventional models. The parallel arrangement of contractile filaments is maintained despite the fact that individual cells are spindle-shaped. This is accomplished through filament attachment to membrane-associated dense plaques that are in turn connected to similar structures on neighboring cells. Intracellularly, the parallel arrangement is maintained despite the centrally located nucleus. This is accomplished by attachment of actin filaments to the nuclear envelope and making the nucleus a force transmitting structure. The results suggest that smooth muscle cells in tissue form a mechanical syncytium and are able to function properly only as a group.

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Section: Discussioncontrasting

confidence: 73%

Contractile filament architecture and force transmission in swine airway smooth muscle

Kuo

Seow

2004

Journal of Cell Science

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“…Tropomyosin may lend structural stability to the microfilaments (38,39) in addition to functioning as a regulator protein (see below), and a-actinin, which is thought to be involved in the linkage of muscle thin filaments to the Z line of skeletal muscle (40,41), may be a factor in coupling cytoplasmic microfilaments of nonmuscle cells to the plasma membrane. In this regard, as in others, nonmuscle cells may be more similar to smooth muscle cells (42) than to skeletal muscle.…”

Section: Morphology and Ultrastructuresupporting

confidence: 62%

Biochemistry of actomyosin-dependent cell motility (a review).

Korn¹

1978

Proc. Natl. Acad. Sci. U.S.A.

449

108

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Actins akd myosins similar to the major proteins of muscle are the major molecular components of intricate mechanochemical systems that perform numerous vital motility and structural functions in all eukaryotic cells. In this article, after a brief summary of the morphological distribution and ultrastructure of actin, myosin, and interrelated proteins of nonmuscle cells, our present knowledge of their biochemistry is critically appraised from the perspective that understanding complex cellular processes depends ultimately on the identification, purification, and biochemical characterization of the proteins involved. Although few conclusions are reached, possible molecular mechanisms for cellular regulation of actin polymerization, filament association, actomyosin ATPase activity, and mechanochemical coupling are discussed and a number of potentially fruitful directions for further research are suggested. These include comparative biochemical investigations and the study of the interaction of heterologous proteins, but particular emphasis is given to the need for quantitative studies at the molecular level of motility proteins purified from a single cellular source.Three mechanisms, ultrastructurally, biochemically, and mechanically distinct, have evolved for cell motility. Two of these, bacterial flagella (1, 2) and eukaryotic flagella (3-6), serve to move cells through fluid media, but they function differently. The third motile mechanism, that based on cytoplasmic microfilaments, is responsible for ameboid-type movement of a cell on a solid substratum. The major component of cytoplasmic microfilaments is the protein actin. Presumably, myosin (which is an ATPase that forms an enzymatically active complex with actin) provides the energy for the motility events, while a number of other proteins maintain the dynamic structural organization of the system and regulate its action. Similar systems in all eukaryotic cells (protist, plant, and animal, and including cells that also possess flagella) provide the mechanochemical basis for many other diverse cellular activities, including cytoplasmic streaming and saltatory movements, phagocytosis and secretory processes, cell division and possibly chromosome segregation, changes in cell shape, and probably even the regulation of the topographical distribution of membrane proteins and functional interconnections of the cell membrane with the nucleus (7-15). Some of these functions may have preceded in evolution the role of actin and myosin in ameboid movement. In their most recently evolved forms, actin and myosin comprise the highly structured contractile systems of muscles.Actomyosin-based cell motility and related phenomena such as the cytoskeletal role of microfilaments and the interaction of microfilaments with cell membranes are increasingly the subjects of investigation at the cellular level and in crude cell extracts. I believe, however, that to understand the physiology of cellular events it is first necessary to understand their biochemistry. It is necess...

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“…Since smooth muscle contains not only actin filaments but also 7-to 10-nm filaments (for references see ref. 25), our results suggest that at least some of these anti-smooth muscle antibodies might in part be directed against intermediate filaments.…”

Section: Discussionmentioning

confidence: 58%

Visualization of a system of filaments 7-10 nm thick in cultured cells of an epithelioid line (Pt K2) by immunofluorescence microscopy.

Osborn¹,

Franke²,

Weber³

1977

Proc. Natl. Acad. Sci. U.S.A.

151

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During our studies with antibodies against structural proteins of the cytoskeleton of eukaryotic cells we have observed that sera from many normal rabbits decorate a fiber system in cells of the established rat kangaroo cell line Pt K2. The display and organization of these fibers are different from those of microfilament bundles (decorated by antibody to actin) and microtubules (decorated by antibody to tubulin

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A Study of the Mechanism of Contraction in Vertebrate Smooth Muscle

Cited by 60 publications

References 168 publications

Contractile filament architecture and force transmission in swine airway smooth muscle

Contractile filament architecture and force transmission in swine airway smooth muscle

Biochemistry of actomyosin-dependent cell motility (a review).

Visualization of a system of filaments 7-10 nm thick in cultured cells of an epithelioid line (Pt K2) by immunofluorescence microscopy.

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