Stromal interaction molecule 1 (STIM1) regulates sarcoplasmic/endoplasmic reticulum Ca²âº-ATPase 1a (SERCA1a) in skeletal muscle.
Pflugers Arch
; 466(5): 987-1001, 2014 May.
Article
em En
| MEDLINE
| ID: mdl-24077737
ABSTRACT
Stromal interaction molecule 1 (STIM1) mediates Ca2+ movements from the extracellular space to the cytosol through a store-operated Ca2+ entry (SOCE) mechanism in various cells including skeletal muscle cells. In the present study, to reveal the unidentified functional role of the STIM1 C terminus from 449 to 671 amino acids in skeletal muscle, binding assays and quadrupole time-of-flight mass spectrometry were used to identify proteins binding in this region along with proteins that mediate skeletal muscle contraction and relaxation. STIM1 binds to sarcoplasmic/endoplasmic reticulum Ca2+-ATPase 1a (SERCA1a) via this region (called STIM1-SBR). The binding was confirmed in endogenous full-length STIM1 in rabbit skeletal muscle and mouse primary skeletal myotubes via co-immunoprecipitation assay and immunocytochemistry. STIM1 knockdown in mouse primary skeletal myotubes decreased Ca2+ uptake from the cytosol to the sarcoplasmic reticulum (SR) through SERCA1a only at micromolar cytosolic Ca2+ concentrations, suggesting that STIM1 could be required for the full activity of SERCA1a possibly during the relaxation of skeletal muscle. Various Ca2+ imaging experiments using myotubes expressing STIM1-SBR suggest that STIM1 is involved in intracellular Ca2+ distributions between the SR and the cytosol via regulating SERCA1a activity without affecting SOCE. Therefore, in skeletal muscle, STIM1 could play an important role in regulating Ca2+ movements between the SR and the cytosol.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Canais de Cálcio
/
Fibras Musculares Esqueléticas
/
ATPases Transportadoras de Cálcio do Retículo Sarcoplasmático
Tipo de estudo:
Prognostic_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article