Obscurins, cytoskeletal proteins discovered about a decade ago, are encoded by the single OBSCN gene and have been primarily studied in vertebrate striated muscles. The giant (~720-900 kDa) obscurin isoforms intimately surround sarcomeres at M-bands and Z-disks, where obscurins participate in their assembly, stability, and integration with other sarcomeric elements. The PI and her primary mentor (Dr. Kontrogianni- Konstantopoulos) are at the forefront of characterizing this novel family of proteins. Recently, the PI has identified a novel obscurin isoform (obscD), resulting from complex differential splicing at the 3' end of the gene that preferentially concentrates at the intercalated disc (ID) of cardiomyocytes. The ID is a unique membrane microdomain that mediates mechanical and electrical coupling between neighboring cells, allowing the synchronous beating of the heart. Importantly, mutations and disruptions of ID proteins interrupt regular heart function, consequently leading to heart disease. Consistent with its ID localization,biochemical assays indicate that obscD exists in a complex with other proteins of the ID proteome. Furthermore, preliminary proteomic analysis has indicated that obscD is regulated via phosphorylation, and its phosphorylation state is altered in the dystrophic disease model. This project aims to elucidate the function that obscD plays at the ID and determine the role of obscD's phosphorylation in physiology and pathophysiology. The PI has assembled an accomplished individualized mentoring committee who will provide the necessary training and support to accomplish the proposed research, as well as facilitate the growth of the PI. The PI will remain at UM SOM, working under the guidance of Drs. Kontrogianni-Konstantopoulos, Rogers, and Stanley. Additionally, the PI will also benefit from the enrichment of Dr. Sellers, at nearby NIH. Through this mentoring team and the collaborations set up by the PI, she will have access to both routine and state-of-the-art equipment and reagents necessary to successfully and efficiently complete the proposed research. In addition, the PI will have excellent resources for career development at the UM SOM and NIH campuses. The proposed research and career development plan will enable the PI to investigate the phosphorylation of obscD and elucidate its in vivo physiological and pathophysiological function at the ID. Furthermore, they will facilitate her development as a diversified independent muscle biology investigator who integrates traditional biochemical and molecular biology techniques with whole tissue translational approaches.

Public Health Relevance

Systematic beating of the heart requires the rapid transmission of mechanical and electrical activity of individual heart cells through specialized cell-?cell junctions. Disruption in the components of these junctions interrupts regular heart function and leads to heart disease. The goal of this proposal is to characterize a newly identified component of this junction, obscurin‐D, in health and disease.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Transition Award (R00)
Project #
5R00HL116778-05
Application #
9405908
Study Section
Special Emphasis Panel (NSS)
Program Officer
Shi, Yang
Project Start
2016-01-15
Project End
2018-12-31
Budget Start
2018-01-01
Budget End
2018-12-31
Support Year
5
Fiscal Year
2018
Total Cost
Indirect Cost
Name
Ohio State University
Department
Physiology
Type
Schools of Medicine
DUNS #
832127323
City
Columbus
State
OH
Country
United States
Zip Code
43210
Manring, Heather R; Carter, Olivia A; Ackermann, Maegen A (2017) Obscure functions: the location-function relationship of obscurins. Biophys Rev 9:245-258
Hu, Li-Yen R; Ackermann, Maegen A; Hecker, Peter A et al. (2017) Deregulated Ca2+ cycling underlies the development of arrhythmia and heart disease due to mutant obscurin. Sci Adv 3:e1603081
Ackermann, Maegen A; King, Brendan; Lieberman, Nicole A P et al. (2017) Novel obscurins mediate cardiomyocyte adhesion and size via the PI3K/AKT/mTOR signaling pathway. J Mol Cell Cardiol 111:27-39
Ackermann, Maegen A; Petrosino, Jennifer M; Manring, Heather R et al. (2017) TGF-?1 affects cell-cell adhesion in the heart in an NCAM1-dependent mechanism. J Mol Cell Cardiol 112:49-57
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 (2015) Links between mTOR and the immunoproteasome: Therapeutic targets for cardiac hypertrophy? J Mol Cell Cardiol 89:113-5
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