Tropomyosin-Troponin Assembly

Cohen, Carolyn; Caspar, D. L. D.; Johnson, J. P.; Nauss, Kathleen M.; Margossian, Sarkis S.; Parry, David

doi:10.1101/sqb.1973.037.01.039

Cited by 66 publications

(24 citation statements)

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“…nation of these. Tropomyosin is known to be an a-helical protein both in skeletal muscle (5) and in nonmuscle cells (6,7), and the extended configuration of this molecule may function to induce actin filaments to assemble in straight filamentous bundles. In this way the absence of tropomyosin from the fluorescent foci may allow actin filaments in these foci to have a more flexible configuration and interact with a-actinin in order to form nucleation centers and direct the outward polymerization of the filament bundles that extend from the vertices of the network to the edges of the cell.…”

Section: Discussionmentioning

confidence: 99%

Actin, alpha-actinin, and tropomyosin interaction in the structural organization of actin filaments in nonmuscle cells.

Lazarides¹

1976

The Journal of Cell Biology

443

206

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During the spreading of a population of rat embryo cells, approximately 40% of the cells develop a strikingly regular network which precedes the formation of the straight actin filament bundles seen in the fully spread out cells. Immunofluorescence studies with antibodies specific for the skeletal muscle structural proteins actin, oz-actinin, and tropomyosin indicate that this network is composed of foci containing actin and a-actinin, connected by tropomyosin-associated actin filaments. Actin filaments, having both tropomyosin and a-actinin associated with them, are also seen to extend from the vertices of this network to the edges of the cell. These results demonstrate a specific interaction of a-actinin and tropomyosin with actin filaments during the assembly and organization of the actin filament bundles of tissue culture cells. The three-dimensional network they form may be regarded as the structural precursor and the vertices of this network as the organization centers of the ultimately formed actin filament bundles of the fully spread out cells.

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Section: Discussionmentioning

confidence: 99%

Actin, alpha-actinin, and tropomyosin interaction in the structural organization of actin filaments in nonmuscle cells.

Lazarides¹

1976

The Journal of Cell Biology

443

206

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“…Troponin T primarily serves to bind the troponin complex to tropomyosin. Troponin C binds available Ca 2+ and thus releases the inhibitory action of troponin I; this action forces tropomyosin into a configurational change, thereby allowing interaction between actin and myosin to commence (Cohen et al, 1972). The biochemical and biophysical interaction between the myosin molecules of the thick filaments and the polymerized actin of the thin filaments produce force and shortening during ventricular systole.…”

Section: Myosin Activity As An Index Of Physiological Vs Pathologicamentioning

confidence: 99%

The cardiac hypertrophy process. Analyses of factors determining pathological vs. physiological development.

Wikman‐Coffelt¹,

Parmley²,

Mason³

1979

Circulation Research

261

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COMPLICATED and even contradictory concepts concerning the biochemical and physiological aspects of cardiac hypertrophy are less enigmatic if we first discern whether the type of hypertrophy analyzed is physiological or pathological; i.e., whether factors secondary to the process of hypertrophy have induced the heart to augment or depress its mechanical function. In this review physiological hypertrophy is defined as hypertrophy accompanied by a normal or augmented contractile state in which the maximum rate at which myosin hydrolyzes ATP and the maximum velocity of muscle shortening are either normal or elevated. Pathological hypertrophy, on the other hand, is associated with depressed contractility without necessarily concordant heart failure, in which case the rate of myosin ATPase activity and the velocity of muscle shortening are decreased. Both types of hypertrophy may be considered compensatory in that the heart biochemically and physiologically adjusts to cellular alterations that occur according to the severity of the workload. Thus, our definition is not the same as that provided by Meerson (1976), since he did not distinguish between the two types of hypertrophy described here.To understand better the evolution of the cardiac hypertrophy process into physiological or pathological hypertrophy, this review is concerned with the immediate inciting stimuli of cardiac hypertrophy, the mechanism of its development, the various stages in its development, and its regional localization. We also are concerned with the dependency of

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“…Tropomyosin is a rod-shaped molecule about 40 nm long constructed from two alpha-helical chains arranged, in register, in a parallel coiled-coil configuration (Caspar et al, 1969;Cohen et al, 1972;Stewart, 1975b). These molecules polymerize by binding end-to-end and about nine residues probably overlap between consecutive molecules (Parry, 1975;Johnson & Smillie, 1977).…”

Section: Results a N D Discussionmentioning

confidence: 99%

“…Figure 4 illustrates the molecular arrangement in the unit cell of tropomyosin magnesium paracrystals. The molecules are arranged antiparallel and overlap by about two-thirds of their length (Caspar et al, 1969;Cohen et al, 1972;Ohtsuki, 1974) and staining of Cys-190 has shown that this long overlap involves the C-terminal portions of the molecules (Stewart, 1975a;Stewart & Diakiw, 1978). Detailed comparison of the positive staining pattern with the amino-acid sequence has given an estimate of 176+6 residues for the extent of the C-terminal overlap (Stewart, 1981).…”

Section: Results a N D Discussionmentioning

confidence: 99%

Cryo‐electron microscopy of tropomyosin magnesium paracrystals

Stewart

Lepault

1985

Journal of Microscopy

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SUMMARY Magnesium paracrystals of tropomyosin have been examined in thin films of vitreous ice by electron microscopy. This material is radiation sensitive, with damage being located near the molecular ends. However, low‐dose images show a repeating pattern of pairs of dark lines every 40 nm which indicates that the structure has been well preserved. These dark lines are separated by about 15 nm and probably represent extra protein density at the molecular ends. It has not been possible previously to see this feature by electron microscopy. We also demonstrate that the mercurial p‐chloro‐mercuribenzoate (PCMB) attached to the tropomyosin thiol at residue 190 can be detected in unstained paracrystals embedded in vitreous ice.

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Tropomyosin-Troponin Assembly

Cited by 66 publications

References 0 publications

Actin, alpha-actinin, and tropomyosin interaction in the structural organization of actin filaments in nonmuscle cells.

Actin, alpha-actinin, and tropomyosin interaction in the structural organization of actin filaments in nonmuscle cells.

The cardiac hypertrophy process. Analyses of factors determining pathological vs. physiological development.

Cryo‐electron microscopy of tropomyosin magnesium paracrystals

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