1. Avian synaptopodin 2 (fesselin) stabilizes myosin filaments and actomyosin in the presence of ATP.
- Author
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Kingsbury NL, Renegar RH, and Chalovich JM
- Subjects
- Actins metabolism, Actins ultrastructure, Actomyosin metabolism, Actomyosin ultrastructure, Animals, Avian Proteins isolation & purification, Avian Proteins metabolism, Avian Proteins ultrastructure, Cytoskeleton metabolism, Cytoskeleton ultrastructure, Gizzard, Avian, Kinetics, Membrane Proteins isolation & purification, Membrane Proteins metabolism, Membrane Proteins ultrastructure, Microfilament Proteins isolation & purification, Microfilament Proteins metabolism, Microfilament Proteins ultrastructure, Microscopy, Electron, Transmission, Muscle, Smooth metabolism, Myosin Subfragments chemistry, Myosin Subfragments isolation & purification, Myosin Subfragments metabolism, Myosin Subfragments ultrastructure, Protein Stability, Rabbits, Secretory Vesicles metabolism, Secretory Vesicles ultrastructure, Smooth Muscle Myosins isolation & purification, Smooth Muscle Myosins metabolism, Smooth Muscle Myosins ultrastructure, Turkeys, Actins chemistry, Actomyosin chemistry, Adenosine Triphosphate metabolism, Avian Proteins chemistry, Cytoskeleton chemistry, Membrane Proteins chemistry, Microfilament Proteins chemistry, Smooth Muscle Myosins chemistry
- Abstract
Smooth muscle cells maintain filaments of actin and myosin in the presence of ATP, although dephosphorylated myosin filaments and actin-myosin interactions are unstable under those conditions in vitro. Several proteins that stabilize myosin filaments and that stabilize actin-myosin interactions have been identified. Fesselin or synaptopodin 2 appears to be another such protein. Rapid kinetic measurements and electron microscopy demonstrated that fesselin, isolated from turkey gizzard muscle, reduced the rate of dissociation of myosin filaments. Addition of fesselin increased both the length and thickness of myosin filaments. The rate of detachment of myosin, but not heavy meromyosin, from actin was also greatly reduced by fesselin. Data from this study suggest that fesselin stabilizes myosin filaments and tethers myosin to actin. These results support the view that one role of fesselin is to organize contractile units of myosin and actin.
- Published
- 2013
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