Abstract
Thin filament regulation of muscle contraction is believed to be mediated by both Ca2+ and strongly bound myosin cross-bridges. We found that secophalloidin (SPH, 5-8 mM) activates cross-bridge cycling without Ca2+ causing isometric force comparable to that induced by Ca2+. At saturated [SPH], Ca2+ further increased force by 20%. SPH-induced force was reversible upon washing with a relaxing solution. However, there was more than 30% irreversible loss in subsequent Ca2+-activated force. We hypothesize that SPH activates muscle via strongly bound cross-bridges. SPH-activated contraction provides a new model for studying the role of Ca2+ and cross-bridges in muscle regulation.
Original language | English (US) |
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Pages (from-to) | 201-204 |
Number of pages | 4 |
Journal | FEBS Letters |
Volume | 519 |
Issue number | 1-3 |
DOIs | |
State | Published - May 22 2002 |
Keywords
- Activation
- Cardiac muscle
- Contraction
- Regulation
- Secophalloidin
ASJC Scopus subject areas
- Biophysics
- Structural Biology
- Biochemistry
- Molecular Biology
- Genetics
- Cell Biology