PUBLICATION
In vitro and in vivo single myosin step-sizes in striated muscle
- Authors
- Burghardt, T.P., Sun, X., Wang, Y., Ajtai, K.
- ID
- ZDB-PUB-160106-8
- Date
- 2015
- Source
- Journal of muscle research and cell motility 36(6): 463-77 (Journal)
- Registered Authors
- Sun, Xiaojing
- Keywords
- Cardiac myosin step-frequency, Cardiac myosin step-size, High throughput Qdot assay, In vivo single myosin imaging, Second characterization, Skeletal muscle myosin mechanics
- MeSH Terms
-
- Actins/metabolism
- Animals
- Muscle, Skeletal/metabolism*
- Muscle, Striated/metabolism*
- Myosin Light Chains/metabolism*
- Swine
- PubMed
- 26728749 Full text @ J. Muscle Res. Cell Motil.
Citation
Burghardt, T.P., Sun, X., Wang, Y., Ajtai, K. (2015) In vitro and in vivo single myosin step-sizes in striated muscle. Journal of muscle research and cell motility. 36(6):463-77.
Abstract
Myosin in muscle transduces ATP free energy into the mechanical work of moving actin. It has a motor domain transducer containing ATP and actin binding sites, and, mechanical elements coupling motor impulse to the myosin filament backbone providing transduction/mechanical-coupling. The mechanical coupler is a lever-arm stabilized by bound essential and regulatory light chains. The lever-arm rotates cyclically to impel bound filamentous actin. Linear actin displacement due to lever-arm rotation is the myosin step-size. A high-throughput quantum dot labeled actin in vitro motility assay (Qdot assay) measures motor step-size in the context of an ensemble of actomyosin interactions. The ensemble context imposes a constant velocity constraint for myosins interacting with one actin filament. In a cardiac myosin producing multiple step-sizes, a "second characterization" is step-frequency that adjusts longer step-size to lower frequency maintaining a linear actin velocity identical to that from a shorter step-size and higher frequency actomyosin cycle. The step-frequency characteristic involves and integrates myosin enzyme kinetics, mechanical strain, and other ensemble affected characteristics. The high-throughput Qdot assay suits a new paradigm calling for wide surveillance of the vast number of disease or aging relevant myosin isoforms that contrasts with the alternative model calling for exhaustive research on a tiny subset myosin forms. The zebrafish embryo assay (Z assay) performs single myosin step-size and step-frequency assaying in vivo combining single myosin mechanical and whole muscle physiological characterizations in one model organism. The Qdot and Z assays cover "bottom-up" and "top-down" assaying of myosin characteristics.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping