scholarly journals 3P170 Photoregulation of smooth muscle myosin ATPase activity by photochromic molecule

2004 ◽  
Vol 44 (supplement) ◽  
pp. S232
Author(s):  
M. Yamada ◽  
S. Maruta
Keyword(s):  
Smooth Muscle ◽  
Atpase Activity ◽  
Smooth Muscle Myosin ◽  
Myosin Atpase ◽  
Myosin Atpase Activity ◽  
Muscle Myosin

Polylysine activates smooth muscle myosin ATPase activity via induction of a 10S to 6S transition

1993 ◽  
Vol 265 (2) ◽  
pp. C379-C386 ◽  
Author(s):  
P. T. Szymanski ◽  
D. G. Ferguson ◽  
R. J. Paul
Keyword(s):  
Smooth Muscle ◽  
Atpase Activity ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Myosin Atpase ◽  
Solution Viscosity ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Myosin Atpase Activity ◽  
Muscle Myosin

Polylysine (10-13 kDa) stimulates contraction in smooth muscle skinned fibers and activates actomyosin adenosinetriphosphatase (ATPase) activity in the absence of myosin light chain phosphorylation [P. T. Szymanski and R. J. Paul. Adv. Exp. Med. 304: 363-368, 1991; P. T. Szymanski, J. D. Strauss, G. Doerman, J. DiSalvo, and R. J. Paul. Am J. Physiol. 262 (Cell Physiol. 31): C1445-C1455, 1992]. To provide further information on the mechanism of polylysine action on contractility in smooth muscle, we investigated its effect on ATPase activity and conformation of purified gizzard myosin. We report here that polylysine directly stimulates myosin ATPase activity in a concentration-dependent manner. This stimulation could be completely abolished with the addition of heparin, a negatively charged heteropolysaccharide. Polylysine (10 microM) increases myosin ATPase activity to a level similar to that of myosin phosphorylation. Addition of 10 microM polylysine to phosphorylated myosin [with myosin light chain kinase and adenosine 5'-O-(3-thiotriphosphate) (ATP gamma S), to approximately 1.9 mol P/mol myosin], however, did not further stimulate ATPase activity. At 0.2 M KCl (the salt concentration at which myosin exists primary in the 10S form), the addition of polylysine increases myosin ATPase activity to a level comparable to that of untreated myosin in 0.3 M KCl. These changes parallel the increase in solution viscosity elicited by polylysine. These results suggest that polylysine induces a transition in myosin conformation from the 10S to the 6S form, and this was confirmed by electron microscopy.(ABSTRACT TRUNCATED AT 250 WORDS)

Correlation between cardiac muscle myosin ATPase activity and velocity of muscle shortening

1979 ◽  
Vol 21 (3) ◽  
pp. 235-245 ◽  
Author(s):  
Rita A. Carey ◽  
Alfred A. Bove ◽  
Richard L. Coulson ◽  
James F. Spann
Keyword(s):  
Atpase Activity ◽  
Cardiac Muscle ◽  
Myosin Atpase ◽  
Myosin Atpase Activity ◽  
Muscle Shortening ◽  
Muscle Myosin

scholarly journals Myosins of secretory tissues

1978 ◽  
Vol 77 (3) ◽  
pp. 827-836 ◽  
Author(s):  
RE Ostlund ◽  
JT Leung ◽  
DM Kipnis
Keyword(s):  
New York ◽  
Smooth Muscle ◽  
Salivary Gland ◽  
Ionic Strength ◽  
Smooth Muscle Myosin ◽  
Myosin Atpase ◽  
Cell Fractionation ◽  
Secretory Tissue ◽  
Low Ionic Strength ◽  
Muscle Myosin

Myosin has been purified from the principal pancreatic islet of catfish, hog salivary gland, and hog pituitary. Use of the protease inhibitor Trasylol (FBA Pharmaceuticals, New York) was essential in the isolation of pituitary myosin. Secretory tissue myosins were very similar to smooth muscle myosin, having a heavy chain of 200,000 daltons and light chains of 14,000 and 19,000 daltons. Salivary gland myosin cross-reacted with antibodies directed toward both smooth muscle myosin and fibroblast myosin, but not with antiskeletal muscel myosin serum. The specific myosin ATPase activity measured in 0.6 M KCl was present. Tissues associated with secretion of hormone granules contained substantial amounts of this ATPase, rat pancreatic islets having 4.5 times that of rat liver. Activation of low ionic strength myosin ATPase by actin could not be demonstrated despite adequate binding of the myosin to muscle actin and elution by MgATP. The myosins were located primarily in the cytoplasm as determined by cell fractionation and were quite soluble in buffers of low ionic strength.

scholarly journals Degradation of smooth-muscle myosin by trypsin-like serine proteinases.

1982 ◽  
Vol 201 (2) ◽  
pp. 267-278 ◽  
Author(s):  
J Kay ◽  
R F Siemankowski ◽  
L M Siemankowski ◽  
D E Goll
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Atpase Activity ◽  
Heavy Chain ◽  
Light Chain ◽  
Regulatory Light Chain ◽  
Smooth Muscle Myosin ◽  
Heavy Meromyosin ◽  
Bovine Trypsin ◽  
Muscle Myosin

1. Hydrolysis of the myosins from smooth and from skeletal muscle by a rat trypsin-like serine proteinase and by bovine trypsin at pH 7 is compared. 2. Proteolysis of the heavy chains of both myosins by the rat enzyme proceeds at rates approx. 20 times faster than those obtained with bovine trypsin. Whereas cleavage of skeletal-muscle myosin heavy chain by both enzymes results in the generation of conventional products i.e. heavy meromyosin and light meromyosin, the heavy chain of smooth-muscle myosin is degraded into a fragment of mol. wt. 150000. This is dissimilar from heavy meromyosin and cannot be converted into heavy meromyosin. It is shown that proteolysis of the heavy chain takes place in the head region. 3. The ‘regulatory’ light chain (20kDa) of smooth-muscle myosin is degraded very rapidly by the rat proteinase. 4. The ability of smooth-muscle myosin to have its ATPase activity activated by actin in the presence of a crude tropomyosin fraction on introduction of Ca2+ is diminished progressively during exposure to the rat proteinase. The rate of loss of the Ca2+-activated actomyosin ATPase activity is very similar to the rate observed for proteolysis of the heavy chain and 3-4 times slower than the rate of removal of the so-called ‘regulatory’ light chain. 5. The significance of these findings in terms of the functional organization of the smooth muscle myosin molecule is discussed. 6. Since the degraded myosin obtained after exposure to very small amounts of the rat proteinase is no longer able to respond to Ca2+, i.e. the functional activity of the molecule has been removed, the implications of a similar type of proteolysis operating in vivo are considered for myofibrillar protein turnover in general, but particularly with regard to the initiation of myosin degradation, which is known to take place outside the lysosome (i.e. at neutral pH).

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