Nedd4-2 regulates surface expression and may affect N-glycosylation of hyperpolarization-activated cyclic nucleotide-gated (HCN)-1 channels.
FASEB J
; 28(5): 2177-90, 2014 May.
Article
de En
| MEDLINE
| ID: mdl-24451387
ABSTRACT
HCN channels are important regulators of neuronal excitability. The proper function of these channels is governed by various mechanisms, including post-translational modifications of channel subunits. Here, we provide evidence that ubiquitination via a ubiquitin ligase, neuronal precursor cell expressed developmentally downregulated (Nedd)-4-2, is involved in the regulation of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels. We identified a PY motif (L/PPxY), the characteristic binding motif for Nedd4-2 in the C terminus of the HCN1 subunit, and showed that HCN1 and Nedd4-2 interacted both in vivo (rat hippocampus, neocortex, and cerebellum) and in vitro [human embryonic kidney 293 (HEK293) cells], resulting in increased HCN1 ubiquitination. Elimination of the PY motif reduced, but did not abolish, Nedd4-2 binding, which further involved a stretch of â¼100 aa downstream in the HCN1 C terminus. Coexpression of Nedd4-2 and HCN1 drastically reduced the HCN1-mediated h-current amplitude (85-92%) in Xenopus laevis oocytes and reduced surface expression (34%) of HCN1 channels in HEK293 cells, thereby opposing effects of tetratricopeptide repeat-containing Rab8b interacting protein (TRIP8b)-(1a-4), an auxiliary subunit that promotes HCN1 surface expression. Regulation may further include N-glycosylation of HCN1 channels, which is significantly enhanced by TRIP8b(1a-4), but may be reduced by Nedd4-2. Taken together, our data indicate that Nedd4-2 plays an important role in the regulation of HCN1 trafficking and may compete with TRIP8b(1a-4) in this process.
Mots clés
Texte intégral:
1
Collection:
01-internacional
Base de données:
MEDLINE
Sujet principal:
Membrane cellulaire
/
Régulation de l'expression des gènes
/
Ubiquitin-protein ligases
/
Complexes de tri endosomique requis pour le transport
/
Canaux contrôlés par les nucléotides cycliques et activés par l'hyperpolarisation
Type d'étude:
Prognostic_studies
Limites:
Animals
/
Female
/
Humans
Langue:
En
Journal:
FASEB J
Sujet du journal:
BIOLOGIA
/
FISIOLOGIA
Année:
2014
Type de document:
Article
Pays d'affiliation:
Allemagne