Abstract
Myosin from chicken intestinal brush borders is phosphorylated on its heavy chains at threonine by a kinase isolated from brush borders. In contrast to other heavy chain kinases, the brush border kinase activity is dependent on calcium and calmodulin. The partially purified preparation also phosphorylated myosin on its light chains at serine, but in a calmodulin-independent manner. Phosphorylation of the light chains in the absence of calmodulin or both heavy and light chains in the presence of calmodulin activated its actin-activated ATPase activity about 10-fold, to about 50 nmol/min per mg.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adenosine Triphosphatases / metabolism
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Animals
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Calcium / pharmacology*
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Calcium-Calmodulin-Dependent Protein Kinases*
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Calmodulin / pharmacology*
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Chickens
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Intestines
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Microvilli / enzymology*
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Myosins / metabolism*
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Phosphorylation
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Phosphotransferases / isolation & purification
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Phosphotransferases / metabolism*
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Protozoan Proteins
Substances
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Calmodulin
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Protozoan Proteins
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Phosphotransferases
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Calcium-Calmodulin-Dependent Protein Kinases
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myosin-heavy-chain kinase
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Adenosine Triphosphatases
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Myosins
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Calcium