Investigating Eukaryotic Elongation Factor 2 Kinase/Eukaryotic Translation Elongation Factor 2 Pathway Regulation and Its Role in Protein Synthesis Impairment during Disuse-Induced Skeletal Muscle Atrophy.

Autor:	Vilchinskaya N; Myology Laboratory, Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia., Lim WF; Department of Paediatrics, University of Oxford, Children's Hospital, John Radcliffe, Oxford, United Kingdom; Institute of Developmental and Regenerative Medicine, University of Oxford, Oxford, United Kingdom; MDUK Oxford Neuromuscular Centre, Oxford, United Kingdom., Belova S; Myology Laboratory, Institute of Biomedical Problems, Russian Academy of Sciences, Moscow, Russia., Roberts TC; Department of Paediatrics, University of Oxford, Children's Hospital, John Radcliffe, Oxford, United Kingdom; Institute of Developmental and Regenerative Medicine, University of Oxford, Oxford, United Kingdom; MDUK Oxford Neuromuscular Centre, Oxford, United Kingdom., Wood MJA; Department of Paediatrics, University of Oxford, Children's Hospital, John Radcliffe, Oxford, United Kingdom; Institute of Developmental and Regenerative Medicine, University of Oxford, Oxford, United Kingdom; MDUK Oxford Neuromuscular Centre, Oxford, United Kingdom., Lomonosova Y; Department of Paediatrics, University of Oxford, Children's Hospital, John Radcliffe, Oxford, United Kingdom; Institute of Developmental and Regenerative Medicine, University of Oxford, Oxford, United Kingdom; MDUK Oxford Neuromuscular Centre, Oxford, United Kingdom. Electronic address: yulia.lomonosova@paediatrics.ox.ac.uk.
Jazyk:	angličtina
Zdroj:	The American journal of pathology [Am J Pathol] 2023 Jun; Vol. 193 (6), pp. 813-828. Date of Electronic Publication: 2023 Mar 05.
DOI:	10.1016/j.ajpath.2023.02.009
Abstrakt:	The principal mechanism underlying the reduced rate of protein synthesis in atrophied skeletal muscle is largely unknown. Eukaryotic elongation factor 2 kinase (eEF2k) impairs the ability of eukaryotic translation elongation factor 2 (eEF2) to bind to the ribosome via T56 phosphorylation. Perturbations in the eEF2k/eEF2 pathway during various stages of disuse muscle atrophy have been investigated utilizing a rat hind limb suspension (HS) model. Two distinct components of eEF2k/eEF2 pathway misregulation were demonstrated, observing a significant (P < 0.01) increase in eEF2k mRNA expression as early as 1-day HS and in eEF2k protein level after 3-day HS. We set out to determine whether eEF2k activation is a Ca 2+ -dependent process with involvement of Cav1.1. The ratio of T56-phosphorylated/total eEF2 was robustly elevated after 3-day HS, which was completely reversed by 1,2-bis (2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester (BAPTA-AM) and decreased by 1.7-fold (P < 0.05) by nifedipine. Transfection of C2C12 with cytomegalovirus promoter (pCMV)-eEF2k and administration with small molecules were used to modulate eEF2k and eEF2 activity. More importantly, pharmacologic enhancement of eEF2 phosphorylation induced phosphorylated ribosomal protein S6 kinase (T389) up-regulation and restoration of global protein synthesis in the HS rats. Taken together, the eEF2k/eEF2 pathway was up-regulated during disuse muscle atrophy involving calcium-dependent activation of eEF2k partly via Cav1.1. The study provides evidence, in vitro and in vivo, of the eEF2k/eEF2 pathway impact on ribosomal protein S6 kinase activity as well as protein expression of key atrophy biomarkers, muscle atrophy F-box/atrogin-1 and muscle RING finger-1. (Copyright © 2023 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.)
Databáze:	MEDLINE
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