Myofibrillogenesis is a highly complex process that depends on the coordinated assembly and integration of a number of contractile, cytoskeletal and signaling proteins into regular arrays, the sarcomeres. Myosin Binding Protein C (MyBP-C), a protein associated with thick filaments, is believed to have both a structural and a regulatory role within the muscle cell, by contributing to the normal assembly and stabilization of thick filaments and modulating the number of myosin heads available for involvement in the contractile cycle. Obscurin, a giant myofibrillar protein, that closely surrounds Z-disks and M-lines, interacts specifically and directly with a novel isoform of MyBP-C slow, MyBP-C(+) slow, that appears to selectively concentrate at the M-line. Consequently, we hypothesize that the binding of obscurin with MyBP-C(+) slow contributes to the assembly, stabilization and maintenance of sarcomeric myosin into regular A-bands, through formation of primitive M-lines that may serve as scaffolding structures. We propose to test this hypothesis through three specific aims: (I) to characterize the novel MyBP-C(+) slow isoform in differentiating and adult skeletal muscle fibers, using a wide array of molecular, cellular and immunological approaches;(II) to study the interaction between obscurin and MyBP-C(+) slow qualitatively, by in vitro and in vivo binding assays, and quantitatively, by surface plasmon resonance technology and (III) to investigate the physiological significance of the binding of obscurin to MyBP-C(+) slow in the assembly and organization of myosin thick filaments into periodic A-bands, using adenovirally-mediated gene transfer and small inhibitory RNA technology. Knowledge gained from the proposed studies will provide new insights into the molecular mechanisms that integrate thick filaments into sarcomeres of normal skeletal fibers and how they are compromised in human muscle disease.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR052768-05
Application #
7796714
Study Section
Skeletal Muscle and Exercise Physiology Study Section (SMEP)
Program Officer
Boyce, Amanda T
Project Start
2006-04-01
Project End
2013-02-28
Budget Start
2010-03-01
Budget End
2013-02-28
Support Year
5
Fiscal Year
2010
Total Cost
$276,996
Indirect Cost
Name
University of Maryland Baltimore
Department
Biochemistry
Type
Schools of Medicine
DUNS #
188435911
City
Baltimore
State
MD
Country
United States
Zip Code
21201
Ackermann, Maegen A; Kerr, Jaclyn P; King, Brendan et al. (2015) The Phosphorylation Profile of Myosin Binding Protein-C Slow is Dynamically Regulated in Slow-Twitch Muscles in Health and Disease. Sci Rep 5:12637
Ackermann, Maegen A; Ward, Christopher W; Gurnett, Christina et al. (2015) Myosin Binding Protein-C Slow Phosphorylation is Altered in Duchenne Dystrophy and Arthrogryposis Myopathy in Fast-Twitch Skeletal Muscles. Sci Rep 5:13235
Ackermann, Maegen A; Shriver, Marey; Perry, Nicole A et al. (2014) Obscurins: Goliaths and Davids take over non-muscle tissues. PLoS One 9:e88162
Ackermann, Maegen A; Patel, Puja D; Valenti, Jane et al. (2013) Loss of actomyosin regulation in distal arthrogryposis myopathy due to mutant myosin binding protein-C slow. FASEB J 27:3217-28
Kontrogianni-Konstantopoulos, Aikaterini (2011) Resisting resistin; it's good for the heart. J Mol Cell Cardiol 51:141-3
Busby, Ben; Oashi, Taiji; Willis, Chris D et al. (2011) Electrostatic interactions mediate binding of obscurin to small ankyrin 1: biochemical and molecular modeling studies. J Mol Biol 408:321-34
Ackermann, Maegen A; Kontrogianni-Konstantopoulos, Aikaterini (2011) Myosin binding protein-C: a regulator of actomyosin interaction in striated muscle. J Biomed Biotechnol 2011:636403
Ackermann, Maegen A; Kontrogianni-Konstantopoulos, Aikaterini (2011) Myosin binding protein-C slow is a novel substrate for protein kinase A (PKA) and C (PKC) in skeletal muscle. J Proteome Res 10:4547-55
Ackermann, Maegen A; Ziman, Andrew P; Strong, John et al. (2011) Integrity of the network sarcoplasmic reticulum in skeletal muscle requires small ankyrin 1. J Cell Sci 124:3619-30
Zhu, F; Wang, P; Kontrogianni-Konstantopoulos, A et al. (2010) Prostaglandin (PG)D(2) and 15-deoxy-Delta(12,14)-PGJ(2), but not PGE(2), mediate shear-induced chondrocyte apoptosis via protein kinase A-dependent regulation of polo-like kinases. Cell Death Differ 17:1325-34

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