Ca2+ regulation not associated with phosphorylation of myosin light chain in aortic intima smooth muscle. II. Effects of regulatory proteins on the actin-myosin interaction.
J Biochem
; 93(6): 1615-9, 1983 Jun.
Article
em En
| MEDLINE
| ID: mdl-6224781
ABSTRACT
Contractile and regulatory proteins were prepared from bovine aortic intima, and actin from bovine stomach smooth and rabbit skeletal muscles. In the desensitized and reconstituted actomyosin system, the superprecipitation activity was measured by the turbidity method. Superprecipitation of each system was not exhibited even in the presence of Ca ions, but was observable only in the presence of tropomyosin and Ca ions, while 20,000-dalton light chain of myosin remained dephosphorylated during the reaction. Addition of tropomyosin to the reconstituted acto-myosin digest system (trypsin-digested myosin was devoid of 20,000-dalton light chain) also restored the Ca2+-sensitivity. These results indicate that the phosphorylation of myosin light chain is not a crucial step in the contraction of aortic intima smooth muscle. For full activation of the actin-myosin-ATP interaction, additional factors other than the myosin light chain kinase are required, although some contribution of the kinase to the full activation cannot be ruled out.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Aorta
/
Actomiosina
/
Cálcio
/
Miosinas
/
Músculo Liso Vascular
Tipo de estudo:
Risk_factors_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
1983
Tipo de documento:
Article