Epithelial junctions depend on intercellular trans-interactions between the Na,K-ATPase ß1 subunits.
J Biol Chem
; 286(29): 25801-12, 2011 Jul 22.
Article
em En
| MEDLINE
| ID: mdl-21642423
ABSTRACT
N-Glycans of the Na,K-ATPase ß1 subunit are important for intercellular adhesion in epithelia, suggesting that epithelial junctions depend on N-glycan-mediated interactions between the ß1 subunits of neighboring cells. The level of co-immunoprecipitation of the endogenous ß1 subunit with various YFP-linked ß1 subunits expressed in Madin-Darby canine kidney cells was used to assess ß1-ß1 interactions. The amount of co-precipitated endogenous dog ß1 was greater with dog YFP-ß1 than with rat YFP-ß1, showing that amino acid-mediated interactions are important for ß1-ß1 binding. Co-precipitation of ß1 was also less with the unglycosylated YFP-ß1 than with glycosylated YFP-ß1, indicating a role for N-glycans. Mixing cells expressing dog YFP-ß1 with non-transfected cells increased the amount of co-precipitated ß1, confirming the presence of intercellular (YFP-ß1)-ß1 complexes. Accordingly, disruption of intercellular junctions decreased the amount of co-precipitated ß1 subunits. The decrease in ß1 co-precipitation both with rat YFP-ß1 and unglycosylated YFP-ß1 was associated with decreased detergent stability of junctional proteins and increased paracellular permeability. Reducing N-glycan branching by specific inhibitors increased (YFP-ß1)-ß1 co-precipitation and strengthened intercellular junctions. Therefore, interactions between the ß1 subunits of neighboring cells maintain integrity of intercellular junctions, and alterations in the ß1 subunit N-glycan structure can regulate stability and tightness of intercellular junctions.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
ATPase Trocadora de Sódio-Potássio
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Células Epiteliais
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Junções Intercelulares
Limite:
Animals
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Humans
Idioma:
En
Revista:
J Biol Chem
Ano de publicação:
2011
Tipo de documento:
Article