1. Calponin reduces shortening velocity in skinned taenia coli smooth muscle fibres
- Author
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Peter Strasser, J. Victor Small, Martin Engström, Kurt I. Anderson, Åsa Jaworowski, Mario Gimona, and Anders Arner
- Subjects
Time Factors ,Colon ,Swine ,Muscle Fibers, Skeletal ,Kinetics ,Calponin ,Biophysics ,Muscle Proteins ,macromolecular substances ,In Vitro Techniques ,Myosins ,Biology ,Biochemistry ,Protein filament ,Smooth muscle ,Motility assay, in vitro ,Structural Biology ,Isometric Contraction ,Genetics ,medicine ,Animals ,Muscle, Skeletal ,Molecular Biology ,Shortening velocity ,Calcium metabolism ,chemistry.chemical_classification ,Dose-Response Relationship, Drug ,Calcium-Binding Proteins ,Microfilament Proteins ,Stomach ,Muscle, Smooth ,Cell Biology ,musculoskeletal system ,Taenia coli ,Molecular biology ,Actins ,Peptide Fragments ,In vitro ,Amino acid ,Dose–response relationship ,medicine.anatomical_structure ,chemistry ,biology.protein ,Calcium - Abstract
Calponin (4.1–5.9 μM, pig stomach) inhibited maximal shortening velocity (Vmax) by 20–25% with only minor influence on force in skinned smooth muscle from guinea-pig taenia coli activated at different Ca2+ levels and with thiophosphorylation. Similar results were obtained with a fragment of the N-terminal 1–228 amino acids engineered using a mouse cDNA construct (5.4 μM). Both the native calponin and the fragment inhibited actin filament sliding in a graded manner in an in vitro motility assay. We conclude that calponin influences the kinetics of the actin-myosin interaction in the organised smooth muscle contractile system and that engineered fragments of calponin can be used to probe its action in muscle fibres. The effects can be due to an introduction of an internal load during filament sliding, possibly by decreasing the detachment rates and increasing the cross-bridge time spent in the attached state.
- Published
- 1995
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