SAP97 blocks the RXR ER retention signal of NMDA receptor subunit GluN1-3 through its SH3 domain.
Biochim Biophys Acta
; 1853(2): 489-99, 2015 Feb.
Article
em En
| MEDLINE
| ID: mdl-25499266
ABSTRACT
SAP97 is directly involved in exporting NMDA receptors with a specific subunit composition from the endoplasmic reticulum (ER). Characterization of the interactions between SAP97 and an NMDA receptor splice variant, GluN1-3, and of the effects on forward trafficking revealed that an ER-level interaction blocked the RXR ER-retention motif in the GluN1-3 cytoplasmic C-terminus in the context of both reporter molecules and full-length receptors. Binding of SAP97 to the PDZ-binding domain of GluN1-3 was required, but the blockade of ER-retention was mediated by the SH3-GuK domains coupled with the action of the N-terminus of SAP97. While other domains of SAP97 were involved in forward trafficking of GluN1-3 out of the ER, the SH3 domain was necessary and sufficient to block the ER retention. This is the first direct evidence for the masking of ER-retention signals by PDZ domain-containing proteins, and provides detailed underlying mechanistic requirements. Such a mechanism could be central to modulating the ER exit of receptors into local, non-conventional or conventional, secretory pathways in neurons.
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MEDLINE
Assunto principal:
Receptores de N-Metil-D-Aspartato
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Domínios de Homologia de src
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Subunidades Proteicas
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Proteínas Adaptadoras de Transdução de Sinal
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Receptores X de Retinoides
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Retículo Endoplasmático
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Proteínas de Membrana
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article