Synthetic myosin filaments from vertebrate smooth muscle

Kaminer, Benjamin

doi:10.1016/0022-2836(69)90315-5

Cited by 55 publications

(24 citation statements)

References 23 publications

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“…Variations in density in longitudinally sectioned material may correspond to regions of cross bridges . The diameter and the length of the thick filaments observed in this study were not significantly different from the respective parameters of synthetic (Kaminer, 1969) or isolated (Shoenberg, 1969) myosin filaments obtained from chicken gizzard muscle, under optimal conditions of producing synthetic or isolated filaments . Direct comparison of the latter studies with our results, however, is not entirely feasible, because, as pointed out elsewhere (Somlyo and Somlyo, 1968), the myosins isolated from different vertebrate smooth muscles may differ biochemically .…”

Section: Transversely-sectioned Myofilamentsmentioning

confidence: 69%

“…Furthermore, within the range of uncertainty of any electron microscope survey, the number of thick filaments and the ease of demonstrating them did not vary whether the muscles were contracted with norepinephrine or relaxed by theophylline or in Ca++-free media . The latter observation is not necessarily inconsistent with the divalent cation requirements for isolating thick filaments (Kaminer, 1969 ;Shoenberg, 1969) reflect the hollow cores seen in the thick myofilaments of freeze-substituted, vascular smooth muscle (Pease, 1968) as well as in a number of conventionally fixed, striated muscles (for review see Pepe, 1971) . Variations in density in longitudinally sectioned material may correspond to regions of cross bridges .…”

Section: Transversely-sectioned Myofilamentsmentioning

confidence: 94%

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Thick Filaments in Vascular Smooth Muscle

Devine

Somlyo

1971

The Journal of Cell Biology

101

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Two sets of myofilaments were demonstrated after incubation of strips of rabbit portalanterior mesenteric vein under moderate stretch in a physiological salt solution . Thick filaments had a mean diameter of 18 nm and reached a maximum length of 1 .4 µm with a mean length of 0 .61 µm . In transverse sections, 2 .5-5 nm particles were resolved as subunits of the thick filaments . Thin filaments had an average diameter of 8 .4 nm and generally conformed to the structure believed to represent actin filaments in smooth and striated muscles . In the areas of maximum concentration there were 160-328 thick filaments/µm 2 and the lowest ratio of thin to thick filaments was 12 :1 . Thick filaments were present in approximately equal numbers in vascular smooth muscle relaxed by theophylline, in Ca++-free solution, or contracted by norepinephrine . The same preparatory procedures used with vascular smooth muscle also enabled us to visualize thick filaments in guinea pig and rabbit taenia coli and vas deferens .Thick filaments in vertebrate smooth muscle have been observed in only a relatively few studies (

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Section: Transversely-sectioned Myofilamentsmentioning

confidence: 69%

Section: Transversely-sectioned Myofilamentsmentioning

confidence: 94%

Thick Filaments in Vascular Smooth Muscle

Devine

Somlyo

1971

The Journal of Cell Biology

101

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“…The configuration and dimensions of the myosin aggregates extracted from platelets were identical to those extracted from vertebrate smooth muscle (23) and synthetically prepared myosin from striated muscle (9). Immunochemical, or histochemical analyses as well as X-ray diffraction studies are needed for full characterization of these proteins on the molecular level.…”

Section: Methodsmentioning

confidence: 96%

“…For the purpose of isolating myosin filaments from platelets the procedure of Kaminer was followed (23). To 1 ml packed bovine platelets, 10 ml 0.6 M KCl was added at pH 6.5.…”

Section: Methodsmentioning

confidence: 99%

The Actin and Myosin Filaments of Human and Bovine Blood Platelets

Zucker‐Franklin¹,

Grusky²

1972

J. Clin. Invest.

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A B S T R A C T The contractility of platelets has been attributed to an actomyosin-like protein which has been well defined on a physicochemical basis. Moreover, platelets contain ±80 A filaments which resemble actin filaments in smooth muscle. Studies were undertaken on human and bovine platelets to better define the morphologic structures which may subserve this contractile function. In order to identify actin, the ability of the filaments to react with heavy meromyosin (HMM) was tested. Accordingly, platelets were glycerinated and treated with HMM. In addition, platelet actin was extracted, reacted with HMM, and examined by negative staining. In both instances typical arrowhead structures with clearly defined polarity and a periodicity of ±360 A formed. As is the case with purified muscle actin, the complexes were dissociable with Mg-ATP. The formation of myosin-like filaments was observed when osmotically shocked platelets were incubated with MgCla and excess ATP. These "thick" filaments measured 250-300 A in width, tapered at both ends and often occurred in clumps. They resembled aggregates of thick filaments described in contracted smooth muscle. Extraction of platelets by methods suitable for the demonstration of myosin showed filaments with an average length of 0.3 /, a smooth shaft, and frayed or bulbous ends. These appeared identical to those seen in synthetically prepared myosin of striated muscle. It is suggested that the filaments described here represent the actin and myosin of platelets.

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“…Preliminary studies with intermediate (200-kV) stereo-electron microscopy of thick (2400-3600 A) sections and reconstruction of serial sections suggests a true thick filament length of approximately 2.2 J1ffi (Ashton, Somlyo, and Somlyo, unpublished observations). Thick filaments in homogenates from gizzard are approximately 0.5 Jim (Rice et at., 1966;Shoenberg, 1969) and filaments synthesized from smooth muscle myosin reached an average maximal length of 0.6 Jim (Kaminer, 1969), but the short lengths may be due to suboptimal preparatory conditions. Experimental variables can greatly influence the length of myosin filaments synthesized from striated muscle myosin (Sanger, 1971).…”

Section: Filament Organization a Myofilaments: Thin (Actin) Andmentioning

confidence: 98%

Ultrastructure of Smooth Muscle

Somlyo

1975

Smooth Muscle

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Synthetic myosin filaments from vertebrate smooth muscle

Cited by 55 publications

References 23 publications

Thick Filaments in Vascular Smooth Muscle

Thick Filaments in Vascular Smooth Muscle

The Actin and Myosin Filaments of Human and Bovine Blood Platelets

Ultrastructure of Smooth Muscle

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