Efforts in this proposal focus on determining the mechanisms of regulation of vertebrate myosin-I. Myosin-I isoforms are the single-headed, membrane-associated members of the myosin superfamily that are found in most eukaryotic cells. Myosin-Is comprise the largest unconventional myosin family found in humans (eight genes). The large size, diversity, and expression profile of vertebrate myosin-I isoforms distinguishes it as one of the most important classes of unconventional myosins. Myosin-Is play essential roles in membrane dynamics, cytoskeletal structure, mechanical signal-transduction, and endosome processing. However, very little is known about the cellular regulation of this important class of motors. Therefore our efforts in this proposal focus on understanding vertebrate myosin-I regulation. We will use a combination of cell biological, biophysical, and biochemical techniques to investigate the following specific aims: 1. Biochemical and cellular interactions of myosin-I with myosin-I binding proteins. In an exciting discovery, we found a family of EF-hand-containing myristoylated proteins that bind to myosin-I isoforms. We will investigate the binding of these proteins to myosin-I, and we will examine the role of these proteins in regulating the interaction of myosin-I with cellular membranes. 2. Biochemical and cellular interactions of myosin-I with lipid membranes. We will investigate the mechanism and regulation of myosin-I association with lipid membranes. We will investigate the ability of calcium to regulate the association of myosin-I with membranes, and we will investigate the ability of myosin-I to sequester lipids important for cellular signaling. 3. Microfilament-based regulation of myosin-I. We will investigate the ability of nonmuscle tropomyosin isoforms to regulate myosin-I. We will determine if tropomyosin isoforms differentially regulate myosin-I isoforms, and we will determine the relationship between myosin-I concentrations and tropomyosin regulation.
| Greenberg, Michael J; Shuman, Henry; Ostap, E Michael (2017) Measuring the Kinetic and Mechanical Properties of Non-processive Myosins Using Optical Tweezers. Methods Mol Biol 1486:483-509 |
| McIntosh, Betsy B; Ostap, E Michael (2016) Myosin-I molecular motors at a glance. J Cell Sci 129:2689-95 |
| Pyrpassopoulos, Serapion; Arpa?, Göker; Feeser, Elizabeth A et al. (2016) Force Generation by Membrane-Associated Myosin-I. Sci Rep 6:25524 |
| Greenberg, Michael J; Arpa?, Göker; Tüzel, Erkan et al. (2016) A Perspective on the Role of Myosins as Mechanosensors. Biophys J 110:2568-76 |
| Kee, Anthony J; Yang, Lingyan; Lucas, Christine A et al. (2015) An actin filament population defined by the tropomyosin Tpm3.1 regulates glucose uptake. Traffic 16:691-711 |
| Greenberg, Michael J; Lin, Tianming; Shuman, Henry et al. (2015) Mechanochemical tuning of myosin-I by the N-terminal region. Proc Natl Acad Sci U S A 112:E3337-44 |
| Shuman, Henry; Greenberg, Michael J; Zwolak, Adam et al. (2014) A vertebrate myosin-I structure reveals unique insights into myosin mechanochemical tuning. Proc Natl Acad Sci U S A 111:2116-21 |
| Ayloo, Swathi; Lazarus, Jacob E; Dodda, Aditya et al. (2014) Dynactin functions as both a dynamic tether and brake during dynein-driven motility. Nat Commun 5:4807 |
| Greenberg, Michael J; Shuman, Henry; Ostap, E Michael (2014) Inherent force-dependent properties of ?-cardiac myosin contribute to the force-velocity relationship of cardiac muscle. Biophys J 107:L41-4 |
| Pyrpassopoulos, Serapion; Shuman, Henry; Ostap, E Michael (2013) Method for measuring single-molecule adhesion forces and attachment lifetimes of protein-membrane interactions. Methods Mol Biol 1046:389-403 |
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