scholarly journals Preparation and characterization of bovine aortic actin

1985 ◽  
Vol 228 (2) ◽  
pp. 433-441 ◽  
Author(s):  
J C Cavadore ◽  
C Axelrud-Cavadore ◽  
P Berta ◽  
M C Harricane ◽  
J Haiech
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle Actin ◽  
Original Method ◽  
Muscle Actin ◽  
Dependent Protein Kinase ◽  
Skeletal Muscle Myosin ◽  
Tryptophan Residues ◽  
Dependent Protein ◽  
Muscle Myosin

A functional vascular smooth-muscle actin from bovine aorta was purified to homogeneity by an original method and was able to polymerize. Aortic actin is composed of two major isoforms and at least two minor ones. This actin was not phosphorylated by either cyclic AMP-dependent protein kinase or C kinase. The physical properties of aortic actin were found to be very similar to those of skeletal-muscle actin, except for amino acid composition (three tryptophan residues instead of four). The aortic actin and skeletal-muscle actin differ in the extent of activation of the Mg-dependent ATPase of skeletal-muscle myosin.

scholarly journals A comparison of the effects of calponin on smooth and skeletal muscle actomyosin systems in the presence and absence of caldesmon

1992 ◽  
Vol 288 (3) ◽  
pp. 733-739 ◽  
Author(s):  
S J Winder ◽  
C Sutherland ◽  
M P Walsh
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Smooth Muscle Actin ◽  
Smooth Muscle Myosin ◽  
Muscle Actin ◽  
Heavy Meromyosin ◽  
Muscle System ◽  
Skeletal Muscle Myosin ◽  
Actomyosin Atpase ◽  
Muscle Myosin

Thiosphosphorylated smooth muscle myosin and skeletal muscle myosin, both of which express Ca(2+)-independent actin-activated MgATPase activity, were used to examine the functional effects of calponin and caldesmon separately and together. Separately, calponin and caldesmon inhibited the actin-activated MgATPase activities of thiophosphorylated smooth muscle myosin and skeletal muscle myosin, calponin being significantly more potent in both systems. Calponin-mediated inhibition resulted from the interaction of calponin with actin since it could be reversed by increasing the actin concentration. Caldesmon had no significant influence on the calponin-induced inhibition of the smooth muscle actomyosin ATPase, nor did calponin have a significant effect on caldesmon-induced inhibition. In the skeletal muscle system, however, caldesmon was found to override the inhibitory effect of calponin. This difference probably reflects the lower affinity of skeletal muscle actin for calponin compared with that of smooth muscle actin. Calponin inhibition of skeletal muscle actin-activated myosin MgATPase was not significantly affected by troponin/tropomyosin, suggesting that the thin filament can readily accommodate calponin in addition to the troponin complex, or that calponin may be able to displace troponin. Calponin also inhibited acto-phosphorylated smooth muscle heavy meromyosin and acto-skeletal muscle heavy meromyosin MgATPases. The most appropriate protein preparations for analysis of the regulatory effects of calponin in the actomyosin system therefore would be smooth muscle actin, tropomyosin and thiophosphorylated myosin, and for analysis of the kinetic effects of calponin on the actomyosin ATPase cycle they would be smooth muscle actin, tropomyosin and phosphorylated heavy meromyosin, due to the latter's solubility.

Proteins of the contractile mechanism of mammalian smooth muscle and their possible location in the cell

1964 ◽  
Vol 160 (981) ◽  
pp. 517-524 ◽  
Keyword(s):  
Skeletal Muscle ◽  
Smooth Muscle ◽  
Sedimentation Rate ◽  
Striated Muscle ◽  
Muscle Actin ◽  
Trypsin Treatment ◽  
Skeletal Muscle Myosin ◽  
Uterine Smooth Muscle ◽  
Muscle Myosin ◽  
Viscous Behaviour

Dorothy M. Needham speaking. Since the pioneer work of Csapo and his colleagues, beginning about fifteen years ago, it has been realized that from uterine smooth muscle can be extracted a protein closely resembling skeletal-muscle actomyosin in its viscous behaviour, sedimentation rate and electrophoretic mobility. (See, for example, Csapo 1948, 1949, 1950, 1959; Csapo, Erdos, Naeslund & Snellman 1950; Naeslund & Snellman 1951). Later work, in which the properties of purified preparations of myosin, actin and actomyosin have been studied, bears out these earlier conclusions. Thus, for example, we have shown (Needham & Williams 1963 b ) that skeletal-muscle myosin will react normally with uterus actin to give the highly viscous actomyosin; and similarly uterus myosin with skeletal-muscle actin. In both types of experiment the results indicated that the two proteins associated together in about the same proportions as when both are derived from skeletal muscle. Uterus actomyosin may be fragmented by carefully controlled trypsin treatment giving light and heavy meromyosins which, so far as they have been studied, show similar properties to the meromyosins from skeletal-muscle actomyosin (Needham & Williams 1959; Cohen, Lowey & Kucera 1961). Smooth muscle, however, does contain very strikingly less actomyosin than striated muscle, only 6 to 10 mg/g wet wt as compared with about 70 mg/g wet wt in skeletal muscle (Needham & Williams 1963 a ).

scholarly journals Skeletal myosin heavy chain function in cultured lung myofibroblasts

2003 ◽  
Vol 163 (1) ◽  
pp. 119-129 ◽  
Author(s):  
Nancy A. Rice ◽  
Leslie A. Leinwand
Keyword(s):  
Skeletal Muscle ◽  
Promoter Activity ◽  
Molecular Mechanisms ◽  
Smooth Muscle Actin ◽  
Myogenic Regulatory Factor ◽  
Skeletal Muscle Myosin ◽  
Heavy Chains ◽  
Skeletal Myosin ◽  
Muscle Genes ◽  
Muscle Myosin

Myofibroblasts are unique contractile cells with both muscle and nonmuscle properties. Typically myofibroblasts are identified by the expression of α smooth muscle actin (ASMA); however some myofibroblasts also express sarcomeric proteins. In this study, we show that pulmonary myofibroblasts express three of the eight known sarcomeric myosin heavy chains (MyHCs) (IIa, IId, and embryonic) and that skeletal muscle myosin enzymatic activity is required for pulmonary myofibroblast contractility. Furthermore, inhibition of skeletal myosin activity and myofibroblast contraction results in a decrease in both ASMA and skeletal MyHC promoter activity and ASMA protein expression, suggesting a potential coupling of skeletal myosin activity and ASMA expression in myofibroblast differentiation. To understand the molecular mechanisms whereby skeletal muscle genes are regulated in myofibroblasts, we have found that members of the myogenic regulatory factor family of transcription factors and Ca2+-regulated pathways are involved in skeletal MyHC promoter activity. Interestingly, the regulation of skeletal myosin expression in myofibroblasts is distinct from that observed in muscle cells and suggests that cell context is important in its control.

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