To understand the regulation and mechanism of smooth muscle contraction and how actin and myosin interact in nonmuscle cells, we have been using various assays of myosin function. One of these, the in vitro motility assay, involves the visualization, in the fluorescent microscope, of the ATP-dependent movement of fluorescently-labeled actin filaments over a surface coated with myosin molecules. The movement of both smooth and nonmuscle myosin is dependent on phosphorylation of the regulatory light chain. Unphosphorylated myosin does not support movement, but does interact weakly with actin. Smooth and nonmuscle myosins translocate actin filaments slowly compared to skeletal muscle myosin, reflecting their quantitively different kinetics. If the slowly cycling smooth or nonmuscle myosin is mixed with the faster cycling skeletal muscle myosin, the composite velocity is dominated by the slower cycling myosin. Interestingly, the noncycling unphosphorylated smooth and nonmuscle myosin can also slow the faster cycling myosins, presumably by creating an internal load through its weak interactions with actin.
| Young, Gavin; Hundt, Nikolas; Cole, Daniel et al. (2018) Quantitative mass imaging of single biological macromolecules. Science 360:423-427 |
| Bond, Lisa M; Sellers, James R; McKerracher, Lisa (2015) Rho kinase as a target for cerebral vascular disorders. Future Med Chem 7:1039-53 |
| Heissler, Sarah M; Sellers, James R (2015) Four things to know about myosin light chains as reporters for non-muscle myosin-2 dynamics in live cells. Cytoskeleton (Hoboken) 72:65-70 |
| Billington, Neil; Revill, Derek J; Burgess, Stan A et al. (2014) Flexibility within the heads of muscle myosin-2 molecules. J Mol Biol 426:894-907 |
| Kim, Kye-Young; Kawamoto, Sachiyo; Bao, Jianjun et al. (2008) The B2 alternatively spliced isoform of nonmuscle myosin II-B lacks actin-activated MgATPase activity and in vitro motility. Biochem Biophys Res Commun 369:124-34 |
| Sellers, James R; Knight, Peter J (2007) Folding and regulation in myosins II and V. J Muscle Res Cell Motil 28:363-70 |
| Iwamoto, Hiroyuki; Oiwa, Kazuhiro; Kovacs, Mihaly et al. (2007) Diversity of structural behavior in vertebrate conventional myosins complexed with actin. J Mol Biol 369:249-64 |
| Kovacs, Mihaly; Thirumurugan, Kavitha; Knight, Peter J et al. (2007) Load-dependent mechanism of nonmuscle myosin 2. Proc Natl Acad Sci U S A 104:9994-9 |
| Kim, Kye-Young; Kovacs, Mihaly; Kawamoto, Sachiyo et al. (2005) Disease-associated mutations and alternative splicing alter the enzymatic and motile activity of nonmuscle myosins II-B and II-C. J Biol Chem 280:22769-75 |
| Kovacs, Mihaly; Wang, Fei; Hu, Aihua et al. (2003) Functional divergence of human cytoplasmic myosin II: kinetic characterization of the non-muscle IIA isoform. J Biol Chem 278:38132-40 |
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