scholarly journals The ATP hydrolysis and phosphate release steps control the time course of force development in rabbit skeletal muscle

2005 ◽  
Vol 563 (3) ◽  
pp. 671-687 ◽  
Author(s):  
John Sleep ◽  
Malcolm Irving ◽  
Kevin Burton
Keyword(s):  
Skeletal Muscle ◽  
Time Course ◽  
Atp Hydrolysis ◽  
Rabbit Skeletal Muscle ◽  
Phosphate Release ◽  
Force Development

Cooperative attachment of cross bridges predicts regulation of smooth muscle force by myosin phosphorylation

2004 ◽  
Vol 287 (3) ◽  
pp. C594-C602 ◽  
Author(s):  
Christopher M. Rembold ◽  
Robert L. Wardle ◽  
Christopher J. Wingard ◽  
Timothy W. Batts ◽  
Elaine F. Etter ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Time Course ◽  
Muscle Force ◽  
Regulatory System ◽  
Force Development ◽  
Cross Bridge ◽  
Cross Bridges ◽  
The Relationship ◽  
Cooperative Activation

Serine 19 phosphorylation of the myosin regulatory light chain (MRLC) appears to be the primary determinant of smooth muscle force development. The relationship between MRLC phosphorylation and force is nonlinear, showing that phosphorylation is not a simple switch regulating the number of cycling cross bridges. We reexamined the MRLC phosphorylation-force relationship in slow, tonic swine carotid media; fast, phasic rabbit urinary bladder detrusor; and very fast, tonic rat anococcygeus. We found a sigmoidal dependence of force on MRLC phosphorylation in all three tissues with a threshold for force development of ∼0.15 mol Pi/mol MRLC. This behavior suggests that force is regulated in a highly cooperative manner. We then determined whether a model that employs both the latch-bridge hypothesis and cooperative activation could reproduce the relationship between Ser19-MRLC phosphorylation and force without the need for a second regulatory system. We based this model on skeletal muscle in which attached cross bridges cooperatively activate thin filaments to facilitate cross-bridge attachment. We found that such a model describes both the steady-state and time-course relationship between Ser19-MRLC phosphorylation and force. The model required both cooperative activation and latch-bridge formation to predict force. The best fit of the model occurred when binding of a cross bridge cooperatively activated seven myosin binding sites on the thin filament. This result suggests cooperative mechanisms analogous to skeletal muscle that will require testing.

scholarly journals The Mg2+-ATPase of rabbit skeletal-muscle transverse tubule is a highly glycosylated multiple-subunit enzyme

1991 ◽  
Vol 278 (2) ◽  
pp. 375-380 ◽  
Author(s):  
T L Kirley
Keyword(s):  
Skeletal Muscle ◽  
Atpase Activity ◽  
Atp Hydrolysis ◽  
Rabbit Skeletal Muscle ◽  
Cross Linking ◽  
Low Concentrations ◽  
Sds Page ◽  
Molecular Masses ◽  
Relationship Of ◽  
Peptide Core

The Mg(2+)-ATPase present in rabbit skeletal-muscle transverse tubules is an integral membrane enzyme which has been solubilized and purified previously in this laboratory [Kirley (1988) J. Biol. Chem. 263, 12682-12689]. The present study indicates that, in addition to the approx. 100 kDa protein (distinct from the sarcoplasmic-reticulum Ca(2+)-ATPase) seen previously to co-purify with the Mg(2+)-ATPase activity, there are also proteins having molecular masses of 160, 70 and 43 kDa. The 70 and 43 kDa glycosylated proteins (50 and 31 kDa after deglycosylation) are difficult to detect by SDS/PAGE before deglycosylation, owing to the broadness of the bands. Additional purification procedures, cross-linking studies and chemical and enzymic deglycosylation studies were undertaken to determine the structure and relationship of these proteins. Both the 97 and 160 kDa proteins were demonstrated to be N-glycosylated at multiple sites, the 97 kDa protein being reduced to a peptide core of 84 kDa and the 160 kDa protein to a peptide core of 131 kDa after deglycosylation. Although the Mg(2+)-ATPase activity is resistant to a number of chemical modification reagents, cross-linking inactivates the enzyme at low concentrations. This inactivation is accompanied by cross-linking of two 97 kDa molecules to one another, suggesting that the 97 kDa protein is involved in ATP hydrolysis. The existence of several proteins along with the inhibition of ATPase activity by cross-linking is consistent with the interpretation of the susceptibility of this enzyme to inactivation by most detergents as being due to the disruption of a protein complex of associated subunits by the inactivating detergents. The 160 kDa glycoprotein can be partially resolved from the Mg(2+)-ATPase activity, and is identified by its N-terminal amino acid sequence as angiotensin-converting enzyme.

scholarly journals Mechanism of K+-induced actin assembly.

1982 ◽  
Vol 93 (3) ◽  
pp. 648-654 ◽  
Author(s):  
J D Pardee ◽  
J A Spudich
Keyword(s):  
Skeletal Muscle ◽  
Dictyostelium Discoideum ◽  
Actin Filaments ◽  
Atp Hydrolysis ◽  
Uv Spectroscopy ◽  
Rabbit Skeletal Muscle ◽  
Actin Assembly ◽  
Filament Formation ◽  
Monomeric Species ◽  
Rapid Formation

The assembly of highly purified actin from Dictyostelium discoideum amoebae and rabbit skeletal muscle by physiological concentrations of KCI proceeds through successive stages of (a) rapid formation of a distinct monomeric species referred to as KCI-monomer, (b) incorporation of KCI-monomers into an ATP-containing filament, and (c) ATP hydrolysis that occurs significantly after the incorporation event. KCI-monomer has a conformation which is distinct from that of either conventional G- or F-actin, as judged by UV spectroscopy at 210-220 nm and by changes in ATP affinity. ATP is not hydrolyzed during conversion of G-actin to KCI-monomer. KCI-monomer formation precedes filament formation and may be necessary for the assembly event. Although incorporation of KCI-monomers into filaments demonstrates lagphase kinetics by viscometry, both continuous absorbance monitoring at 232 nm and rapid sedimentation of filaments demonstrate hyperbolic assembly curves. ATP hydrolysis significantly lags the formation of actin filaments. When half of the actin has assembled, only 0.1 to 0.2 mole of ATP are hydrolyzed per mole of actin present as filaments.

scholarly journals Influence of ionic strength on the time course of force development and phosphate release by dogfish muscle fibres

2005 ◽  
Vol 567 (3) ◽  
pp. 989-1000 ◽  
Author(s):  
Timothy G. West ◽  
Michael A. Ferenczi ◽  
Roger C. Woledge ◽  
N. A. Curtin
Keyword(s):  
Ionic Strength ◽  
Time Course ◽  
Muscle Fibres ◽  
Phosphate Release ◽  
Force Development

scholarly journals Effects of previous activity on the energetics of activation in frog skeletal muscle.

1980 ◽  
Vol 75 (6) ◽  
pp. 617-631 ◽  
Author(s):  
J A Rall
Keyword(s):  
Skeletal Muscle ◽  
Time Delay ◽  
Time Course ◽  
Frog Skeletal Muscle ◽  
Active Force ◽  
Force Development ◽  
Uptake Sites ◽  
Contractile Activation ◽  
Terminal Cisternae ◽  
Activation Heat

Effects of previous activity on the ability of frog skeletal muscle at 0 degrees C to liberate energy associated with contractile activation, i.e., activation heat (AH), have been examined. Earlier work suggests that activation heat amplitude (as measured from muscles stretched to lengths where active force development is nearly abolished) is related to the amount of Ca2+ released upon stimulation. After a twitch, greater than 2 s is required before a second stimulus (AHt) can liberate the same activation heat as a first stimulus (AH infinity), i.e., (AHt)/(AH infinity) = 1 -0.83 e-1.40t, where t is time in seconds. Caffeine introduces a time delay in the recovery of the ability to generate activation heat after a twitch. After a tetanus, the activation heat is depressed to a greater extent at any time than after a twitch. The activation heat elicited by a stimulus 1 s after a tetanus is depressed progressively with respect to tetanus duration up to 3 s. For tetani of 3, 40, and 80 s duration the postetanus activation heat is comparably depressed. The time-course of the recovery of the ability of the muscle to produce activation heat after a tetanus can be described as (AHt)/(AH infinity) = 1 -0.80 e-0.95t -0.20 e-0.02t. Greater than 90 s is required before the posttetanus activation heat is equal to the pretetanus value. The faster phase of recovery is similar to recovery after the twitch and the slower phase may be associated with the return of calcium to the terminal cisternae from uptake sites in the longitudinal sarcoplasmic reticulum.

Control of heat production by the Ca2+-ATPase of rabbit and trout sarcoplasmic reticulum

1998 ◽  
Vol 274 (6) ◽  
pp. C1738-C1744 ◽  
Author(s):  
Leopoldo De Meis
Keyword(s):  
Skeletal Muscle ◽  
Sarcoplasmic Reticulum ◽  
Heat Production ◽  
Atp Hydrolysis ◽  
Rabbit Skeletal Muscle ◽  
Heparin Sodium ◽  
The Difference

The sarcoplasmic reticulum Ca2+-ATPase of rabbit skeletal muscle can convert the energy derived from a Ca2+ gradient into heat (L. de Meis, M. L. Bianconi, and V. A. Suzano. FEBS Lett. 406: 201–204, 1997). In this report, it is shown that this conversion varies depending on the temperature and on whether rabbit (endotherm) or trout (poikilotherm) sarcoplasmic reticulum vesicles are used. The gradient doubled the yield of heat produced during ATP hydrolysis and the calorimetric enthalpy of ATP hydrolysis (Δ H cal) value found with both rabbit and trout varied between −10 and −12 kcal/mol in leaky vesicles (no gradient) and between −20 and −22 kcal/mol with intact vesicles (gradient). For the rabbit, the difference of Δ H cal measured with and without gradient was detected in the range of 30–35°C and disappeared when the temperature was decreased below 30°C. For the trout, the difference was detected between 20 and 25°C and disappeared below 20°C. The effect of the gradient on the Δ H cal for ATP hydrolysis was modified by DMSO, trifluoperazine, and heparin sodium.

UPTAKE OF OXYTOCIN IN TISSUES AFTER INTRAVENOUS ADMINISTRATION OF TRITIATED OXYTOCIN IN RATS

1969 ◽  
Vol 61 (3) ◽  
pp. 432-440 ◽  
Author(s):  
Ingvar Sjöholm ◽  
Gunnar Rydén
Keyword(s):  
Skeletal Muscle ◽  
Distribution Pattern ◽  
Intravenous Injection ◽  
Intravenous Administration ◽  
Time Course ◽  
Tritiated Water ◽  
Preferential Distribution ◽  
Time Period ◽  
Initial Uptake

ABSTRACT The distribution of oxytocin in the kidneys, liver, uterus and skeletal muscle of the rat was followed during 10 min after intravenous injection of tritium labelled oxytocin. Oxytocin was found to be taken up and degraded mainly in the kidneys and the liver. After 150 seconds no intact oxytocin could be detected in these organs. The time course of the distribution of the radioactivity in the liver and the skeletal muscle showed no noteworthy characteristics, whereas a different course was found in the kidneys and in the uterus. In the kidneys, the radioactivity increased continuously from 60 to 200 seconds after the injection, indicating an accumulation of oxytocin or its metabolites in the kidneys. In the uterus a high initial uptake was observed, followed by a decrease of the radioactivity from 60 to 100 seconds after the injection. This distribution pattern was specific to oxytocin, since the uptake of tritiated tyrosine and tritiated water was almost constant during the same time period. These findings may indicate a preferential distribution of oxytocin to the uterus.

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