scholarly journals Differential actin binding along the PEVK domain of skeletal muscle titin

2004 ◽  
Vol 117 (24) ◽  
pp. 5781-5789 ◽  
Author(s):  
A. Nagy
Keyword(s):  
Skeletal Muscle ◽  
Actin Binding ◽  
Pevk Domain

scholarly journals Nexilin, a Cardiomyopathy-Associated F-Actin Binding Protein, Binds and Regulates IRS1 Signaling in Skeletal Muscle Cells

PLoS ONE ◽  
2013 ◽  
Vol 8 (1) ◽  
pp. e55634 ◽  
Author(s):  
Andrew Lee ◽  
Fumihiko Hakuno ◽  
Paul Northcott ◽  
Jeffrey E. Pessin ◽  
Maria Rozakis Adcock
Keyword(s):  
Skeletal Muscle ◽  
Binding Protein ◽  
Muscle Cells ◽  
Skeletal Muscle Cells ◽  
Actin Binding ◽  
Actin Binding Protein

scholarly journals A 72,000-mol-wt protein from tomato inhibits rabbit acto-S-1 ATPase activity.

1983 ◽  
Vol 96 (6) ◽  
pp. 1761-1765 ◽  
Author(s):  
M Vahey
Keyword(s):  
Skeletal Muscle ◽  
Ionic Strength ◽  
Atpase Activity ◽  
Rabbit Skeletal Muscle ◽  
Ion Concentration ◽  
Actin Binding ◽  
Molar Ratio ◽  
Reversible Inhibitor ◽  
Skeletal Muscle Myosin ◽  
Low Ionic Strength

Tomato activation inhibiting protein (AIP) is a molecule of an apparent molecular weight of 72,000 that co-purifies with tomato actin. In an assay system containing rabbit skeletal muscle F-actin and rabbit skeletal muscle myosin subfragment-1 (myosin S-1), tomato AIP dissociated the acto-S-1 complex in the absence of Mg+2ATP and inhibited the ability of F-actin to activate the low ionic strength Mg+2ATPase activity of myosin S-1. At a molar ratio of 5 actin to 1 AIP, a 50% inhibition of the actin-activated Mg+2ATPase activity of myosin S-1 was observed. The inhibition can be reversed by raising the calcium ion concentration to 1 X 10(-5) M. The AIP had no effect on the basal low ionic strength Mg+2ATPase activity of myosin S-1 in the absence of actin. The protein did not bind directly to actin nor did it cause depolymerization or aggregation of F-actin but appeared, instead, to interact with the actin binding site on myosin S-1. Since AIP is a potent, reversible inhibitor of the rabbit acto-S-1 ATPase activity, it is postulated that it may be responsible for the low levels of actin activation exhibited by tomato F-actin fractions containing the AIP.

scholarly journals Alternatively spliced exons of the beta tropomyosin gene exhibit different affinities for F-actin and effects with nonmuscle caldesmon

1995 ◽  
Vol 108 (10) ◽  
pp. 3253-3265 ◽  
Author(s):  
M.F. Pittenger ◽  
A. Kistler ◽  
D.M. Helfman
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Insect Cell ◽  
The Other ◽  
Actin Binding ◽  
Gene Products ◽  
Free Concentration ◽  
Alternatively Spliced ◽  
Beta Gene

The rat beta-tropomyosin (TM) gene expresses two isoforms via alternative RNA splicing, namely skeletal muscle beta-TM and fibroblast TM-1. The latter is also expressed in smooth muscle where it corresponds to smooth muscle beta-TM. Skeletal muscle beta-TM contains exons 7 and 10, whereas exons 6 and 11 are used in fibroblasts and smooth muscle. In order to study the properties of the alternatively spliced proteins, recombinant TMs derived from bacterial and insect cell expression systems were produced, including the normal beta gene products, fibroblast TM-1 and beta skeletal muscle TM, two carboxy-terminal chimeric TMs, TM-6/10 and TM-7/11, as well as a carboxyl-truncated version of each, TM-6Cla and TM-7Cla. The purified TM isoforms were used in actin filament association studies. The apparent TM association constants (Ka) were taken as the free concentration at half saturation and were found to be 6 microM for beta Sk TM, 8.5 for TM-6/10, 25 microM for TM-1, and 30 microM for TM-7/11 at an F-actin concentration of 42 microM. For the truncated TMs, the values determined were higher still but the binding was not carried out to full saturation. Isoforms were also produced using the baculovirus-insect cell system which produces proteins with an acetylated amino terminus as is normally found in vivo. This modification significantly enhanced the F-actin association of TM-1 but not the beta skeletal TM or the other isoforms. Fibroblast TM-2 or TM-3, both products of the alpha gene, enhanced the affinity of TM-1 for F-actin, demonstrating different isoforms can act cooperatively on binding to actin. This effect was not detected with the other expressed beta gene products. The presence of 83 kDa nonmuscle caldesmon was found to enhance the binding of TM-1 for F-actin. This effect was dependent on the presence of both exons 6 and 11, as caldesmon had little effect on the other beta gene products. Collectively these results demonstrate TMs differ in their affinity for F-actin, which can be altered by other TMs or actin-binding proteins. The beta tropomyosin isoforms were fluorescently-tagged and microinjected into cultured cells to study their in vivo localization where it was found that each of the full-length TMs bound to microfilaments but, at the light microscopy level, the isoforms were not differentially localized in these fibroblasts.

Kinetic properties of myosin heavy chain isoforms in mouse skeletal muscle: comparison with rat, rabbit, and human and correlation with amino acid sequence

2004 ◽  
Vol 287 (6) ◽  
pp. C1725-C1732 ◽  
Author(s):  
Oleg Andruchov ◽  
Olena Andruchova ◽  
Yishu Wang ◽  
Stefan Galler
Keyword(s):  
Skeletal Muscle ◽  
Amino Acid ◽  
Myosin Heavy Chain ◽  
Heavy Chain ◽  
Actin Binding ◽  
Kinetic Properties ◽  
Fiber Types ◽  
Mouse Skeletal Muscle ◽  
Structural Variability ◽  
Kinetics Of

Stretch activation kinetics were investigated in skinned mouse skeletal muscle fibers of known myosin heavy chain (MHC) isoform content to assess kinetic properties of different myosin heads while generating force. The time to peak of stretch-induced delayed force increase ( t3) was strongly correlated with MHC isoforms [ t3 given in ms for fiber types containing specified isoforms; means ± SD with n in parentheses: MHCI 680 ± 108 ( 13 ), MHCIIa 110.5 ± 10.7 ( 23 ), MHCIIx(d) 46.2 ± 5.2 ( 20 ), MHCIIb 23.5 ± 3.3 (76)]. This strong correlation suggests different kinetics of force generation of different MHC isoforms in the following order:MHCIIb > MHCIIx(d) > MHCIIa ≫ MHCI. For rat, rabbit, and human skeletal muscles the same type of correlation was found previously. The kinetics decreases slightly with increasing body mass. Available amino acid sequences were aligned to quantify the structural variability of MHC isoforms of different animal species. The variation in t3 showed a correlation with the structural variability of specific actin-binding loops (so-called loop 2 and loop 3) of myosin heads ( r = 0.74). This suggests that alterations of amino acids in these loops contribute to the different kinetics of myosin heads of various MHC isoforms.

scholarly journals Three-dimensional structure of the Z band in a normal mammalian skeletal muscle.

1996 ◽  
Vol 133 (3) ◽  
pp. 571-583 ◽  
Author(s):  
J P Schroeter ◽  
J P Bretaudiere ◽  
R L Sass ◽  
M A Goldstein
Keyword(s):  
Skeletal Muscle ◽  
Cross Sections ◽  
Three Dimensional ◽  
Square Lattice ◽  
Actin Binding ◽  
Dimensional Structure ◽  
Mammalian Skeletal Muscle ◽  
Axial Filament ◽  
Three Dimensional Structure ◽  
Dimensional Reconstruction

The three-dimensional structure of the vertebrate skeletal muscle Z band reflects its function as the muscle component essential for tension transmission between successive sarcomeres. We have investigated this structure as well as that of the nearby I band in a normal, unstimulated mammalian skeletal muscle by tomographic three-dimensional reconstruction from electron micrograph tilt series of sectioned tissue. The three-dimensional Z band structure consists of interdigitating axial filaments from opposite sarcomeres connected every 18 +/- 12 nm (mean +/- SD) to one to four cross-connecting Z-filaments are observed to meet the axial filaments in a fourfold symmetric arrangement. The substantial variation in the spacing between cross-connecting Z-filament to axial filament connection points suggests that the structure of the Z band is not determined solely by the arrangement of alpha-actinin to actin-binding sites along the axial filament. The cross-connecting filaments bind to or form a "relaxed interconnecting body" halfway between the axial filaments. This filamentous body is parallel to the Z band axial filaments and is observed to play an essential role in generating the small square lattice pattern seen in electron micrographs of unstimulated muscle cross sections. This structure is absent in cross section of the Z band from muscles fixed in rigor or in tetanus, suggesting that the Z band lattice must undergo dynamic rearrangement concomitant with crossbridge binding in the A band.

scholarly journals Cryo-electron microscopy structures of pyrene-labeled ADP-Pi- and ADP-actin filaments

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Steven Z. Chou ◽  
Thomas D. Pollard
Keyword(s):  
Electron Microscopy ◽  
Skeletal Muscle ◽  
Active Site ◽  
Actin Filaments ◽  
Actin Polymerization ◽  
Actin Binding ◽  
Muscle Actin ◽  
Hydrophobic Cavity ◽  
Cryo Electron Microscopy ◽  
Kinetics Of

AbstractSince the fluorescent reagent N-(1-pyrene)iodoacetamide was first used to label skeletal muscle actin in 1981, the pyrene-labeled actin has become the most widely employed tool to measure the kinetics of actin polymerization and the interaction between actin and actin-binding proteins. Here we report high-resolution cryo-electron microscopy structures of actin filaments with N-1-pyrene conjugated to cysteine 374 and either ADP (3.2 Å) or ADP-phosphate (3.0 Å) in the active site. Polymerization buries pyrene in a hydrophobic cavity between subunits along the long-pitch helix with only minor differences in conformation compared with native actin filaments. These structures explain how polymerization increases the fluorescence 20-fold, how myosin and cofilin binding to filaments reduces the fluorescence, and how profilin binding to actin monomers increases the fluorescence.

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