Identification of a novel splice variant of neuronal nitric oxide synthase, nNOSß, in myofilament fraction of murine cardiomyocytes.
Nitric Oxide
; 50: 20-27, 2015 11 15.
Article
en En
| MEDLINE
| ID: mdl-26271450
ABSTRACT
Splice variant forms of neuronal nitric oxide synthase (nNOS or NOS1), nNOSα and nNOSµ, are well established to be functionally expressed in discrete compartments in cardiomyocytes (e.g. sarcoplasmic reticulum, SR, caveolae in plasma membrane or mitochondria). So far, whether nNOS is expressed in myofilament fraction of cardiomyocytes and the splice variant form of nNOS are unknown. Immunoblotting results using two nNOS specific antibodies (BD Transduction Laboratories aa 1095-1289 and Santa Cruz Biotechnology aa 2-300) clearly demonstrated that nNOS was abundantly expressed in myofilament-enriched fraction of cardiomyocytes. Whilst the molecular weight of nNOS in membrane/cytosol fractions was â¼165 kDa, nNOS in myofilament was below 140 kDa, suggesting that the predominant splice variant of nNOS in myofilament is nNOSß. RT-PCR results confirmed the expressions of both nNOSα and nNOSß mRNAs in rat cardiomyocytes. Similarly, immunoprecipitation experiments using myofilament lysates of cardiomyocytes identified nNOS with low molecular weight (M.W. â¼140 kDa), confirming nNOSß. Intriguingly, all three splice variants of nNOS were undetectable in the lysates of cardiomyocytes (including myofilament fractions) from nNOS-/- mice (which lacks nNOSα/µ). Furthermore, nNOSß expression in myofilament of cardiomyocytes was not different in hypertensive rats compared to the level expressed in sham. iTRAQ-based quantitative proteomics analysis revealed that nNOS regulates phosphorylations of â¼20 proteins in cardiac myofilaments. Collectively, we provide direct evidence that different splice variants of nNOS are expressed in myofilament and membrane/cytosol fractions of cardiomyocytes. Discrete expressions of various splice variants in different compartments of cardiomyocytes suggest diverse roles nNOS play in healthy and diseased heart.
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1
Colección:
01-internacional
Banco de datos:
MEDLINE
Tipo de estudio:
Diagnostic_studies
Idioma:
En
Revista:
Nitric Oxide
Asunto de la revista:
BIOQUIMICA
/
QUIMICA
Año:
2015
Tipo del documento:
Article