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Mol Cell Biol. 2018 Jun 28;38(14). pii: e00649-17. doi: 10.1128/MCB.00649-17. Print 2018 Jul 15.

Reduction of Cellular Nucleic Acid Binding Protein Encoded by a Myotonic Dystrophy Type 2 Gene Causes Muscle Atrophy.

Author information

1
Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
2
Department of Neurology, St. Josef Hospital, Ruhr University Bochum, Bochum, Germany.
3
Department of Neurology, University of Würzburg, Würzburg, Germany.
4
Division of Surgery, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
5
Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA Lubov.Timchenko@cchmc.org.

Abstract

Myotonic dystrophy type 2 (DM2) is a neuromuscular disease caused by an expansion of intronic CCTG repeats in the CNBP gene, which encodes a protein regulating translation and transcription. To better understand the role of cellular nucleic acid binding protein (CNBP) in DM2 pathology, we examined skeletal muscle in a new model of Cnbp knockout (KO) mice. This study showed that a loss of Cnbp disturbs myofibrillar sarcomeric organization at birth. Surviving homozygous Cnbp KO mice develop muscle atrophy at a young age. The skeletal muscle phenotype in heterozygous Cnbp KO mice was milder, but they developed severe muscle wasting at an advanced age. Several proteins that control global translation and muscle contraction are altered in muscle of Cnbp KO mice. A search for CNBP binding proteins showed that CNBP interacts with the α subunit of the dystroglycan complex, a core component of the multimeric dystrophin-glycoprotein complex, which regulates membrane stability. Whereas CNBP is reduced in cytoplasm of DM2 human fibers, it is a predominantly membrane protein in DM2 fibers, and its interaction with α-dystroglycan is increased in DM2. These findings suggest that alterations of CNBP in DM2 might cause muscle atrophy via CNBP-mediated translation and via protein-protein interactions affecting myofiber membrane function.

KEYWORDS:

CNBP; molecular pathology; muscle atrophy; myotonic dystrophy; unstable repeats

PMID:
29735719
PMCID:
PMC6024164
DOI:
10.1128/MCB.00649-17
[Indexed for MEDLINE]
Free PMC Article

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