Regulation of tension in skinned muscle fibers: effect of high concentrations of Mg-ATP

Orentlicher, M.; Brandt, Philip W.; Reuben, John P.

doi:10.1152/ajpcell.1977.233.5.c127

Cited by 78 publications

(35 citation statements)

References 18 publications

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“…2) . The number of fibers in each condition is listed in Tables II-IV. Contrary to the effect of substrate concentration change (in zero phosphate) reported here, tension in skinned crayfish fibers increases when the substrate is lowered from -15 to 1 mM (Orentlicher et al, 1977) . At constant pCa, pS/ tension curves are bell-shaped (Reuben et al, 1971) .…”

Section: Discussioncontrasting

confidence: 99%

“…In pCa 8, tension is maximal at 3 jim or so, then the fibers relax with further increase in substrate. As the pCa is lowered, the point of maximum tension shifts to lower pS (Brandt et al, 1972 ;Orentlicher et al, 1977 ;Cooke and Bialek, 1979) . To cogently compare our present data on the effect of substrate concentration on the maximum tension with that in the literature, we will have to take into account normalization procedures (see Methods) .…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Effect of cross-bridge kinetics on apparent Ca2+ sensitivity.

Brandt¹,

Cox²,

Kawai³

et al. 1982

The Journal of General Physiology

148

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Three different ways of shifting the pCa/tension curve on the pCa axis have been studied and related to changes in the rate constants of the crossbridge cycle. The curve midpoint shifts to higher pCa's wheel the substrate (Mg-ATP) is reduced from 5 to 0.25 mM, when the phosphate concentration is reduced from 7.5 mM to 0, and when the ionic strength is reduced from 0.200 to 0.120 . The Hill coefficients of the pCa/tension curve in our standard saline (5 mM substrate, 5 mM free ATP, 7.5 mM phosphate, ionic strength 0.200, 15°C) are between 5.1 and 5.6 and fall to 3.0 with the left shift of the curve brought about by reducing both substrate and phosphate. Left shifts of the curve produced by reduction in the ionic strength do not result in a lower Hill coefficient . Reducing either substrate or phosphate is associated with a reduction in the optimal frequency for oscillatory work, but reduction in ionic strength is not so associated . Maximum tension increases with the left shift of the curve brought about by reducing phosphate concentration or ionic strength, but tension decreases with the left shift of the curve accompanying substrate concentration reduction in a phosphate-free saline . We argue that one mechanism for the observed shift of the curve along the pCa axis is the relationship between the time a cross-bridge takes to complete a cycle and the time Ca 2+ stays bound to troponin C (TnC) . If the cycle rate is decreased, a smaller fraction of TnC sites must be occupied to keep a given fraction of cross-bridges active . To illustrate this concept, we present a simplified model of the cross-bridge cycle incorporating the kinetics of Ca binding to TnC.

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Section: Discussioncontrasting

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Effect of cross-bridge kinetics on apparent Ca2+ sensitivity.

Brandt¹,

Cox²,

Kawai³

et al. 1982

The Journal of General Physiology

148

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“…3.4.6 Ecdysozoa, Crustacea-Early work showed that crustacean actomyosin had a chemical composition roughly similar to that of other myosins (Bailey, 1937;Siemankowski and Zobel, 1976), showed typical Ca ++ activated ATPase activity (Humphrey, 1948;Maruyama, 1958aMaruyama, , 1959aMaruyama, , 1968aPortzehl et al, 1964Portzehl et al, , 1965Portzehl et al, , 1969Tomioka et al, 1975;Siemankowski and Zobel, 1976;Orentlicher et al, 1977;Stephenson and Williams, 1980;Goblet and Mounier, 1987;Allhouse et al, 1999c;Shimada et al, 2000;Koenders et al, 2004), and that its temperature dependence matched species' habitat temperature (Shimada et al, 2000).…”

Section: Ecdysozoa Chelicerata-limulus Actomyosin Was Early Isolatedmentioning

confidence: 99%

Invertebrate muscles: Thin and thick filament structure; molecular basis of contraction and its regulation, catch and asynchronous muscle

Hooper

Hobbs

Thuma

2008

Progress in Neurobiology

128

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This is the second in a series of canonical reviews on invertebrate muscle. We cover here thin and thick filament structure, the molecular basis of force generation and its regulation, and two special properties of some invertebrate muscle, catch and asynchronous muscle. Invertebrate thin filaments resemble vertebrate thin filaments, although helix structure and tropomyosin arrangement show small differences. Invertebrate thick filaments, alternatively, are very different from vertebrate striated thick filaments and show great variation within invertebrates. Part of this diversity stems from variation in paramyosin content, which is greatly increased in very large diameter invertebrate thick filaments. Other of it arises from relatively small changes in filament backbone structure, which results in filaments with grossly similar myosin head placements (rotating crowns of heads every 14.5 nm) but large changes in detail (distances between heads in azimuthal registration varying from three to thousands of crowns). The lever arm basis of force generation is common to both vetebrates and invertebrates, and in some invertebrates this process is understood on the near atomic level. Invertebrate actomyosin is both thin (tropomyosin:troponin) and thick (primarily via direct Ca ++ binding to myosin) filament regulated, and most invertebrate muscles are dually regulated. These mechanisms are well understood on the molecular level, but the behavioral utility of dual regulation is less so. The phosphorylation state of the thick filament associated giant protein, twitchin, has been recently shown to be the molecular basis of catch. The molecular basis of the stretch activation underlying asynchronous muscle activity, however, remains unresolved.

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“…The program calculation was used with stability constants listed for Ca 2ϩ (37) and for Sr 2ϩ (38) to keep a final ionic strength at 200 mM. pH was adjusted to 7.0, and ATP was added to each solution at a final concentration of 2.5 mM.…”

Section: Confirmation Of the Glycosylation Type Of Contractile Proteimentioning

confidence: 99%

O-Linked N-Acetylglucosaminylation Is Involved in the Ca2+ Activation Properties of Rat Skeletal Muscle

Hedou¹,

Cieniewski-Bernard

Leroy

et al. 2007

Journal of Biological Chemistry

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O-Linked N-acetylglucosaminylation termed O-GlcNAc is a dynamic cytosolic and nuclear glycosylation that is dependent both on glucose flow through the hexosamine biosynthesis pathway and on phosphorylation because of the existence of a balance between phosphorylation and O-GlcNAc. This glycosylation is a ubiquitous post-translational modification, which probably plays an important role in many aspects of protein functions. We have previously reported that, in skeletal muscle, proteins of the glycolytic pathway, energetic metabolism, and contractile proteins were O-GlcNAc-modified and that O-GlcNAc variations could control the muscle protein homeostasis and be implicated in the regulation of muscular atrophy.In this paper, we report O-N-acetylglucosaminylation of a number of key contractile proteins (i.e. myosin heavy and light chains and actin), which suggests that this glycosylation could be involved in skeletal muscle contraction. Moreover, our results showed that incubation of skeletal muscle skinned fibers in N-acetyl-D-glucosamine, in a concentration solution known to inhibit O-GlcNAc-dependent interactions, induced a decrease in calcium sensitivity and affinity of muscular fibers, whereas the cooperativity of the thin filament proteins was not modified. Thus, our results suggest that O-GlcNAc is involved in contractile protein interactions and could thereby modulate muscle contraction. O-Linked N-acetylglucosaminylation, termed O-GlcNAc,5 is a regulatory post-translational modification that occurs in nuclear and cytosolic proteins, corresponding to the addition of a unique monosaccharide, N-acetyl-D-glucosamine, to a serine and threonine hydroxyl group by a ␤-linkage (1). Because of the existence of the UDP-GlcNAc-peptide-␤-GlcNAc transferase, which transfers the monosaccharide into proteins (2, 3), and the N-acetyl-␤-D-glucosaminidase, which removes it (4), OGlcNAc is more similar to phosphorylation than classical glycosylation. The half-life of the monosaccharide is shorter than the half-life of the protein backbone (5), indicating that the O-GlcNAc cycle could rapidly respond to cellular signals (6). All of the known O-GlcNAc proteins described to date are also phosphoproteins (7) (for review, see Ref. 8). Modifications by O-GlcNAc or phosphorylation could occur on the same site (9) or at neighboring sites (10); this competition between O-GlcNAc and phosphorylation is called the "Yin-Yang" process.O-GlcNAc has been described to play a role in various cell functions: in nuclear transport (11-13); in protein degradation, with a reversible inhibition of the proteasome itself (14) and a protection of the modified protein against proteasomal degradation (9, 15, 16); and in regulation of protein expression, with the regulation of transcription (10, 17-19) and translation (20). The involvement of O-GlcNAc in protein-protein interactions has been described in different biological systems. Indeed, many proteins playing a key role in organization and assembly of cytoskeleton are O-GlcNAc-modified, including cytok...

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Regulation of tension in skinned muscle fibers: effect of high concentrations of Mg-ATP

Cited by 78 publications

References 18 publications

Effect of cross-bridge kinetics on apparent Ca2+ sensitivity.

Effect of cross-bridge kinetics on apparent Ca2+ sensitivity.

Invertebrate muscles: Thin and thick filament structure; molecular basis of contraction and its regulation, catch and asynchronous muscle

O-Linked N-Acetylglucosaminylation Is Involved in the Ca2+ Activation Properties of Rat Skeletal Muscle

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