A toxin-based probe reveals cytoplasmic exposure of Golgi sphingomyelin.
J Biol Chem
; 285(29): 22186-95, 2010 Jul 16.
Article
em En
| MEDLINE
| ID: mdl-20463009
ABSTRACT
Although sphingomyelin is an important cellular lipid, its subcellular distribution is not precisely known. Here we use a sea anemone cytolysin, equinatoxin II (EqtII), which specifically binds sphingomyelin, as a new marker to detect cellular sphingomyelin. A purified fusion protein composed of EqtII and green fluorescent protein (EqtII-GFP) binds to the SM rich apical membrane of Madin-Darby canine kidney (MDCK) II cells when added exogenously, but not to the SM-free basolateral membrane. When expressed intracellularly within MDCK II cells, EqtII-GFP colocalizes with markers for Golgi apparatus and not with those for nucleus, mitochondria, endoplasmic reticulum or plasma membrane. Colocalization with the Golgi apparatus was confirmed by also using NIH 3T3 fibroblasts. Moreover, EqtII-GFP was enriched in cis-Golgi compartments isolated by gradient ultracentrifugation. The data reveal that EqtII-GFP is a sensitive probe for membrane sphingomyelin, which provides new information on cytosolic exposure, essential to understand its diverse physiological roles.
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Esfingomielinas
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Sondas Moleculares
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Venenos de Cnidários
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Complexo de Golgi
Limite:
Animals
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
2010
Tipo de documento:
Article
País de afiliação:
Eslovênia