Abstract
Caldesmon (CaD) is thought to regulate smooth muscle contraction, because it binds actin and inhibits actomyosin interactions. A synthetic actin-binding peptide (GS17C) corresponding to Gly666-Ser682 of chicken gizzard CaD has been shown to induce force development in permeabilized smooth muscle cells. The mechanism of GS17C's action remains unclear, although a structural effect was postulated. By photo-crosslinking and fluorescence quenching experiments with a gizzard CaD fragment (H32K; Met563-Pro771) and its mutants, we showed that GS17C indeed dissociated the C-terminal region of H32K from actin, in a manner similar to extracellular signal-regulated kinase-mediated phosphorylation, thereby reversing the CaD-imposed inhibition and enabling the actomyosin interaction.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Actomyosin / chemistry
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Actomyosin / metabolism
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Amino Acid Substitution
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Animals
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Calmodulin-Binding Proteins / chemistry*
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Calmodulin-Binding Proteins / genetics
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Calmodulin-Binding Proteins / metabolism
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Chickens / metabolism*
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Extracellular Signal-Regulated MAP Kinases / chemistry*
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Extracellular Signal-Regulated MAP Kinases / metabolism
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Gizzard, Avian / chemistry*
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Gizzard, Avian / metabolism
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Muscle Contraction / physiology
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Muscle, Smooth / chemistry*
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Muscle, Smooth / metabolism
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Peptides / chemistry*
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Peptides / genetics
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Peptides / metabolism
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Phosphorylation
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Point Mutation
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Protein Binding
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Rabbits
Substances
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Calmodulin-Binding Proteins
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Peptides
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Actomyosin
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Extracellular Signal-Regulated MAP Kinases