Identification of NPC2 protein as interaction molecule with C2 domain of human Nedd4L.
Epithelial sodium channels (ENaC) located along the aldosterone-sensitive distal nephron (ASDN) play a pivotal role in the homeostasis of sodium balance. Among various modulating proteins, E3 ubiquitin ligase, Nedd4L, binds the PY motif of ENaC COOH terminals and catalyzes ubiquitination of the NH(2) terminal of the protein for subsequent degradation. One of the isoforms of human Nedd4L with evolutionarily new C2 domain was reported to play a significant role for degradating cell surface ENaC with interfering with wild isoforms by us previously. We focused the current analyses on isolating the binding molecules with C2 domain using yeast two-hybrid screening to elucidate further molecular interactions between ENaC and Nedd4L. We found NPC2, also known as HE-1, bind C2 domain of human Nedd4L and express along ASDN colocalized with Nedd4L. Additionally, in experiments using a model of salt-sensitive hypertension in Dahl rats, we provided evidence suggesting that transcriptional regulation and activation of NPC2 protein depends on sodium intake. NPC2 might regulate sodium reabsorption in the terminal nephron by interacting with ENaC-Nedd4L system.
Araki
Naomi
N
Yokohama City University Graduate School of Medicine, Department of Medical Science and Cardio-renal Medicine, Yokohama-city, Kanagawa-ken 236-0004, Japan.
Ishigami
Tomoaki
T
Ushio
Hisako
H
Minegishi
Shintaro
S
Umemura
Masanari
M
Miyagi
Yohei
Y
Aoki
Ichiro
I
Morinaga
Hiroko
H
Tamura
Koichi
K
Toya
Yoshiyuki
Y
Uchino
Kazuaki
K
Umemura
Satoshi
S
D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D056827:Endosomal Sorting Complexes Required for Transport; D005786:Gene Expression Regulation; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D017136:Ion Transport; D000075702:Nedd4 Ubiquitin Protein Ligases; D009399:Nephrons / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D051381:Rats; D020303:Rats, Inbred Dahl; D012964:Sodium / Q000378:metabolism; D014158:Transcription, Genetic; D020798:Two-Hybrid System Techniques; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D019459:Urothelium / Q000378:metabolism; D033921:Vesicular Transport Proteins
D002352:Carrier Proteins; D056827:Endosomal Sorting Complexes Required for Transport; D006023:Glycoproteins; C104585:NPC2 protein, human; D033921:Vesicular Transport Proteins; D012964:Sodium; C000618479:NEDD4L protein, rat; D000075702:Nedd4 Ubiquitin Protein Ligases; C000618485:Nedd4L protein, human; D044767:Ubiquitin-Protein Ligases