Dynamic reorganization of actin cytoskeleton is accomplished by a coordinated regulation of assembly and disassembly of actin filaments. In multicellular organisms, various types of cells utilize different mechanisms to regulate actin filament dynamics. Especially in muscle cells, the actin cytoskeleton is differentiated into myofibrils, which are highly organized contractile apparatuses. The long-term objective of this project is to understand the mechanisms by which the actin cytoskeleton is reorganized into myofibrils during muscle development. The expected outcome of this research will provide insight into molecular basis of morphogenesis of cellular organelles. This proposed project will use the nematode Caenorhabditis elegans as a model system and explore the roles of actin depolymerizing factor (ADF)/cofilin in actin filament dynamics during muscle development. ADF/cofilin enhances actin filament dynamics by depolymerizing and severing actin filaments. In C. elegans, mutations in a gene encoding a muscle-specific ADF/cofilin isoform cause disorganized actin filaments in muscle cells. These studies have suggested that the muscle-specific ADF/cofilin is a critical factor to generate a dynamic state of actin filaments during myofibril assembly.
The aims of this project are: (a) to determine the effects of the muscle-specific ADF/cofilin on actin filament dynamics in vitro, (b) to determine specific roles of severing and depolymerization by ADF/cofilin in myofibril assembly in vivo, (c) to determine the roles of modulators of ADF/cofilin.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR048615-02
Application #
6623253
Study Section
Special Emphasis Panel (ZRG1-CDF-4 (02))
Program Officer
Lymn, Richard W
Project Start
2002-05-01
Project End
2007-04-30
Budget Start
2003-05-01
Budget End
2004-04-30
Support Year
2
Fiscal Year
2003
Total Cost
$250,040
Indirect Cost
Name
Emory University
Department
Pathology
Type
Schools of Medicine
DUNS #
066469933
City
Atlanta
State
GA
Country
United States
Zip Code
30322
Barnes, Dawn E; Watabe, Eichi; Ono, Kanako et al. (2018) Tropomyosin isoforms differentially affect muscle contractility in the head and body regions of the nematode Caenorhabditis elegans. Mol Biol Cell 29:1075-1088
Ono, Shoichiro (2018) Functions of actin-interacting protein 1 (AIP1)/WD repeat protein 1 (WDR1) in actin filament dynamics and cytoskeletal regulation. Biochem Biophys Res Commun 506:315-322
Watabe, Eichi; Ono, Shoichiro; Kuroyanagi, Hidehito (2018) Alternative splicing of the Caenorhabditis elegans lev-11 tropomyosin gene is regulated in a tissue-specific manner. Cytoskeleton (Hoboken) 75:427-436
Ono, Shoichiro (2017) A plague of actin disassembly. J Biol Chem 292:8101-8102
Iwase, Shohei; Ono, Shoichiro (2017) Conserved hydrophobic residues in the CARP/?-sheet domain of cyclase-associated protein are involved in actin monomer regulation. Cytoskeleton (Hoboken) 74:343-355
Barnes, Dawn E; Hwang, Hyundoo; Ono, Kanako et al. (2016) Molecular evolution of troponin I and a role of its N-terminal extension in nematode locomotion. Cytoskeleton (Hoboken) 73:117-30
Hwang, Hyundoo; Barnes, Dawn E; Matsunaga, Yohei et al. (2016) Muscle contraction phenotypic analysis enabled by optogenetics reveals functional relationships of sarcomere components in Caenorhabditis elegans. Sci Rep 6:19900
Ono, Kanako; Ono, Shoichiro (2016) Two distinct myosin II populations coordinate ovulatory contraction of the myoepithelial sheath in the Caenorhabditis elegans somatic gonad. Mol Biol Cell 27:1131-42
Lee, Cho-Yin; Lou, Jizhong; Wen, Kuo-Kuang et al. (2016) Regulation of actin catch-slip bonds with a RhoA-formin module. Sci Rep 6:35058
Nomura, Kazumi; Hayakawa, Kimihide; Tatsumi, Hitoshi et al. (2016) Actin-interacting Protein 1 Promotes Disassembly of Actin-depolymerizing Factor/Cofilin-bound Actin Filaments in a pH-dependent Manner. J Biol Chem 291:5146-56

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