Back to Search
Start Over
Myosin light chain phosphorylation facilitates in vivo myosin filament reassembly after mechanical perturbation.
- Source :
-
American journal of physiology. Cell physiology [Am J Physiol Cell Physiol] 2002 Jun; Vol. 282 (6), pp. C1298-305. - Publication Year :
- 2002
-
Abstract
- Phosphorylation of the 20-kDa regulatory myosin light chain (MLC) of smooth muscle is known to cause monomeric myosins in solution to self-assemble into thick filaments. The role of MLC phosphorylation in thick filament formation in intact muscle, however, is not clear. It is not known whether the phosphorylation is necessary to initiate thick filament assembly in vivo. Here we show, by using a potent inhibitor of MLC kinase (wortmannin), that the MLC phosphorylation and isometric force in trachealis muscle could be abolished without affecting calcium transients. By measuring cross-sectional densities of the thick filaments electron microscopically, we also show that inhibition of MLC phosphorylation alone did not cause disassembly of the filaments. The unphosphorylated thick filaments, however, partially dissolved when the muscle was subjected to oscillatory strains (which caused a 25% decrease in the thick filament density). The postoscillation filament density recovered to the preoscillation level only when wortmannin was removed and the muscle was stimulated. The data suggest that in vivo thick filament reassembly after mechanical perturbation is facilitated by the cyclic MLC phosphorylation associated with repeated stimulation.
- Subjects :
- Androstadienes pharmacology
Animals
Calcium Signaling drug effects
Calcium Signaling physiology
Dogs
Electric Stimulation
Electrophysiology
Enzyme Inhibitors pharmacology
In Vitro Techniques
Isometric Contraction drug effects
Isometric Contraction physiology
Muscle, Smooth drug effects
Muscle, Smooth ultrastructure
Myosins ultrastructure
Phosphorylation drug effects
Swine
Trachea
Wortmannin
Muscle, Smooth metabolism
Myosin Light Chains metabolism
Myosins metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0363-6143
- Volume :
- 282
- Issue :
- 6
- Database :
- MEDLINE
- Journal :
- American journal of physiology. Cell physiology
- Publication Type :
- Academic Journal
- Accession number :
- 11997244
- Full Text :
- https://doi.org/10.1152/ajpcell.00554.2001