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.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM057247-09
Application #
7104815
Study Section
Cell Development and Function Integrated Review Group (CDF)
Program Officer
Rodewald, Richard D
Project Start
1998-08-01
Project End
2007-09-27
Budget Start
2006-08-01
Budget End
2007-09-27
Support Year
9
Fiscal Year
2006
Total Cost
$297,374
Indirect Cost
Name
University of Pennsylvania
Department
Physiology
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
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
Zwolak, Adam; Yang, Changsong; Feeser, Elizabeth A et al. (2013) CARMIL leading edge localization depends on a non-canonical PH domain and dimerization. Nat Commun 4:2523

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