Phosphorylation of thin filaments regulates vascular smooth muscle actomyosin ATPase activity

1980 ◽  
Vol 4 (8) ◽  
pp. 799 ◽  
Author(s):  
S MARSTON ◽  
M WALTERS
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Atpase Activity ◽  
Thin Filaments ◽  
Actomyosin Atpase

scholarly journals Functional interrelationship between calponin and caldesmon

1991 ◽  
Vol 280 (1) ◽  
pp. 33-38 ◽  
Author(s):  
R Makuch ◽  
K Birukov ◽  
V Shirinsky ◽  
R Dabrowska
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Atpase Activity ◽  
Smooth Muscle Contraction ◽  
The Other ◽  
High Concentration ◽  
Thin Filaments ◽  
Actomyosin Atpase ◽  
Molar Excess ◽  
Low Concentrations

Calponin and caldesmon, constituents of smooth-muscle thin filaments, are considered to be potential modulators of smooth-muscle contraction. Both of them interact with actin and inhibit ATPase activity of smooth- and skeletal-muscle actomyosin. Here we show that calponin and caldesmon could bind simultaneously to F-actin when used in subsaturating amounts, whereas each one used in excess caused displacement of the other from the complex with F-actin. Calponin was more effective than caldesmon in this competition: when F-actin was saturated with calponin the binding of caldesmon was eliminated almost completely, whereas even at high molar excess of caldesmon one-third of calponin (relative to the saturation level) always remained bound to actin. The inhibitory effects of low concentrations of calponin and caldesmon on skeletal-muscle actomyosin ATPase were additive, whereas the maximum inhibition of the ATPase attained at high concentration of each of them was practically unaffected by the other one. These data suggest that calponin and caldesmon cannot operate on the same thin filaments. CA(2+)-calmodulin competed with actin for calponin binding, and at high molar excess dissociated the calponin-actin complex and reversed the calponin-induced inhibition of actomyosin ATPase activity.

Effect of caffeine on the Ca2+pool affecting contractility and actomyosin ATPase activity in vascular smooth muscle of rabbit

1993 ◽  
Vol 23 (1) ◽  
pp. 92
Author(s):  
Jin Min Kim ◽  
Young Ho Lee ◽  
Chang Hyun Moon ◽  
Bok Soon Kang ◽  
Doo Hee Kang
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Atpase Activity ◽  
Actomyosin Atpase

scholarly journals Calcium-Dependent Myosin from Insect Flight Muscles

1974 ◽  
Vol 63 (5) ◽  
pp. 553-563 ◽  
Author(s):  
William Lehman ◽  
Belinda Bullard ◽  
Kathleen Hammond
Keyword(s):  
Atpase Activity ◽  
Insect Flight ◽  
Calcium Regulation ◽  
Regulatory Proteins ◽  
Myosin Molecule ◽  
Thin Filaments ◽  
Actomyosin Atpase ◽  
Calcium Dependent ◽  
Regulatory Systems ◽  
Flight Muscles

Calcium regulation of the insect actomyosin ATPase is associated with the thin filaments as in vertebrate muscles, and also with the myosin molecule as in mollusks. This dual regulation is demonstrated using combinations of locust thin filaments with rabbit myosin and locust myosin with rabbit actin; in each case the ATPase of the hybrid actomyosin is calcium dependent. The two regulatory systems are synergistic, the calcium dependency of the locust actomyosin ATPase being at least 10 times that of the hybrid actomyosins described above. Likewise Lethocerus myosin also contains regulatory proteins. The ATPase activity of Lethocerus myosin is labile and is stabilized by the presence of rabbit actin. Tropomyosin activates the ATPase of insect actomyosin and the activation occurs irrespective of whether the myosin is calcium dependent or rendered independent of calcium.

Serum transcriptionally regulates Na(+)-K(+)-ATPase gene expression in vascular smooth muscle cells

1997 ◽  
Vol 273 (3) ◽  
pp. C1088-C1099 ◽  
Author(s):  
J. Nemoto ◽  
S. Muto ◽  
A. Ohtaka ◽  
K. Kawakami ◽  
Y. Asano
Keyword(s):  
Gene Expression ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Atpase Activity ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Fold Increase ◽  
Mrna Levels ◽  
Subunit Protein ◽  
Mrna Induction

The present study was designed to examine the effects of serum on Na(+)-K(+)-ATPase alpha 1- and beta 1-subunit gene expression in cultured vascular smooth muscle cells (VSMC) from rat thoracic aortas. Addition of 10% serum to VSMC for 24 h increased Na(+)-K(+)-ATPase activity 1.5-fold and alpha 1- and beta 1-subunit protein levels 1.9-fold. Serum (10%) caused a 3.5-fold increase in alpha 1-mRNA levels and a 6.7-fold increase in beta 1-mRNA levels, with peak elevations at 12 h. The protein synthesis inhibitor cycloheximide abolished serum-mediated beta 1-mRNA induction but did not affect serum-mediated alpha 1-mRNA induction. Protein kinase C (PKC) inhibitors (staurosporine A or calphostin C) or tyrosine kinase (TK) inhibitors (genistein or herbimycin A) significantly reduced serum-mediated beta 1-mRNA induction but had no effect on serum-mediated alpha 1-mRNA induction. Transfection experiments with the 5'-flanking sequences of the alpha 1- or beta 1-subunit genes linked to the luciferase reporter gene revealed that 10% serum caused 2.8- and 6.5-fold increases in luciferase activity, respectively. Among growth factors, only basic fibroblast growth factor (FGF) enhanced luciferase activities for the alpha 1- and beta 1-subunit genes. We conclude that 1) serum stimulates alpha 1- and beta 1-mRNA expression, alpha 1- and beta 1-subunit protein accumulation, and Na(+)-K(+)-ATPase activity; 2) serum-mediated beta 1-mRNA induction partly requires de novo synthesis of intermediate regulatory proteins and activation of PKC and TK, whereas serum-mediated alpha 1-mRNA induction occurs through PKC- and TK-independent mechanisms; 3) the 5'-flanking regions of the alpha 1- and beta 1-subunit genes are serum responsive; and 4) FGF mimics stimulatory effects of serum on promoter activities for the alpha 1- and beta 1-subunit genes.

scholarly journals Ca2+ can control vascular smooth-muscle thin filaments without caldesmon phosphorylation

1986 ◽  
Vol 237 (2) ◽  
pp. 605-607 ◽  
Author(s):  
S B Marston
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Binding Protein ◽  
Direct Interaction ◽  
Half Time ◽  
Thin Filaments

The Ca2+-dependent regulation of the activation of myosin MgATPase by vascular-smooth-muscle thin filaments involves caldesmon. This effect may be due to the direct interaction of caldesmon with a Ca2+-binding protein such as calmodulin or phosphorylation of caldesmon by a Ca2+-dependent kinase. I have found that Ca2+ switches on aorta thin filaments in less than 10 s, whereas the caldesmon in the thin filaments is phosphorylated only slowly (half-time greater than 10 min) and the maximum phosphorylation is very low (1 molecule per 7 molecules of caldesmon). I conclude that the phosphorylation of caldesmon hypothesis is untenable.

Na+-K+-ATPase in vascular smooth muscle

1986 ◽  
Vol 250 (4) ◽  
pp. C536-C539 ◽  
Author(s):  
J. C. Allen ◽  
S. S. Navran ◽  
A. M. Kahn
Keyword(s):  
Enzyme Activity ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Atpase Activity ◽  
Binding Site ◽  
Aortic Tissue ◽  
Ouabain Binding

Na+-K+-ATPase has been isolated and characterized from canine aortic tissue. The ouabain-sensitive enzyme activity was 24 mumol X mg protein-1 X h-1, and the remaining Mg2+-ATPase activity was 54 mumol X mg protein-1 X h-1. The ratio of Na+-K+-ATPase to ouabain-sensitive K+-phosphatase was 13 to 1, similar to other more homogeneous preparations from other tissues. The dissociation characteristics of the enzyme-glycoside complex of this aortic preparation were the same as for cardiac preparations in that it was stabilized by K+. These data suggest that the nature of both the ATP hydrolytic site of Na+-K+-ATPase and the ouabain binding site are the same in preparations from vascular smooth muscle as in preparations from other tissues.

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