A central core disease mutation in the Ca2+-binding site of skeletal muscle ryanodine receptor impairs single-channel regulation.
Am J Physiol Cell Physiol
; 317(2): C358-C365, 2019 08 01.
Article
em En
| MEDLINE
| ID: mdl-31166712
ABSTRACT
Cryoelectron microscopy and mutational analyses have shown that type 1 ryanodine receptor (RyR1) amino acid residues RyR1-E3893, -E3967, and -T5001 are critical for Ca2+-mediated activation of skeletal muscle Ca2+ release channel. De novo missense mutation RyR1-Q3970K in the secondary binding sphere of Ca2+ was reported in association with central core disease (CCD) in a 2-yr-old boy. Here, we characterized recombinant RyR1-Q3970K mutant by cellular Ca2+ release measurements, single-channel recordings, and computational methods. Caffeine-induced Ca2+ release studies indicated that RyR1-Q3970K formed caffeine-sensitive, Ca2+-conducting channel in HEK293 cells. However, in single-channel recordings, RyR1-Q3970K displayed low Ca2+-dependent channel activity and greatly reduced activation by caffeine or ATP. A RyR1-Q3970E mutant corresponds to missense mutation RyR2-Q3925E associated with arrhythmogenic syndrome in cardiac muscle. RyR1-Q3970E also formed caffeine-induced Ca2+ release in HEK293 cells and exhibited low activity in the presence of the activating ligand Ca2+ but, in contrast to RyR1-Q3970K, was activated by ATP and caffeine in single-channel recordings. Computational analyses suggested distinct structural rearrangements in the secondary binding sphere of Ca2+ of the two mutants, whereas the interaction of Ca2+ with directly interacting RyR1 amino acid residues Glu3893, Glu3967, and Thr5001 was only minimally affected. We conclude that RyR1-Q3970 has a critical role in Ca2+-dependent activation of RyR1 and that a missense RyR1-Q3970K mutant may give rise to myopathy in skeletal muscle.
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Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Ativação do Canal Iônico
/
Cálcio
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Músculo Esquelético
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Canal de Liberação de Cálcio do Receptor de Rianodina
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Mutação de Sentido Incorreto
Tipo de estudo:
Prognostic_studies
Limite:
Animals
/
Humans
Idioma:
En
Revista:
Am J Physiol Cell Physiol
Assunto da revista:
FISIOLOGIA
Ano de publicação:
2019
Tipo de documento:
Article