Unique regulation of human Na+/H+ exchanger 3 (NHE3) by Nedd4-2 ligase that differs from non-primate NHE3s.
Na(+)/H(+) exchanger NHE3 expressed in the intestine and kidney plays a major role in NaCl and HCO3 (-) absorption that is closely linked to fluid absorption and blood pressure regulation. The Nedd4 family of E3 ubiquitin ligases interacts with a number of transporters and channels via PY motifs. A comparison of NHE3 sequences revealed the presence of PY motifs in NHE3s from human and several non-human primates but not in non-primate NHE3s. In this study we evaluated the differences between human and non-primate NHE3s in ubiquitination and interaction with Nedd4-2. We found that Nedd4-2 ubiquitinated human NHE3 (hNHE3) and altered its expression and activity. Surprisingly, rat NHE3 co-immunoprecipitated Nedd4-2, but its expression and activity were not altered by silencing of Nedd4-2. Ubiquitination by Nedd4-2 rendered hNHE3 to undergo internalization at a significantly greater rate than non-primate NHE3s without altering protein stability. Insertion of a PY motif in rabbit NHE3 recapitulated the interaction with Nedd4-2 and enhanced internalization. Thus, we propose a new model where disruption of Nedd4-2 interaction elevates hNHE3 expression and activity.
From the Division of Digestive Diseases, Department of Medicine and.
Yi Ran
YR
No
From the Division of Digestive Diseases, Department of Medicine and.
Peijian
P
He
From the Division of Digestive Diseases, Department of Medicine and.
Byong Kwon
BK
Yoo
From the Division of Digestive Diseases, Department of Medicine and Winship Cancer Institute, Emory University, Atlanta, Georgia 30322 ccyun@emory.edu.
C Chris
CC
Yun
D000595:Amino Acid Sequence; D000818:Animals; D056827:Endosomal Sorting Complexes Required for Transport / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D008322:Mammals / Q000145:classification / Q000235:genetics; D008969:Molecular Sequence Data; D000075702:Nedd4 Ubiquitin Protein Ligases; D009893:Opossums; D010802:Phylogeny; D011485:Protein Binding; D011817:Rabbits; D051381:Rats; D016415:Sequence Alignment; D000074083:Sodium-Hydrogen Exchanger 3; D017923:Sodium-Hydrogen Exchangers / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination
D056827:Endosomal Sorting Complexes Required for Transport; C000613385:SLC9A3 protein, human; C000613387:Slc9a3 protein, rat; D000074083:Sodium-Hydrogen Exchanger 3; D017923:Sodium-Hydrogen Exchangers; C000618479:NEDD4L protein, rat; D000075702:Nedd4 Ubiquitin Protein Ligases; C000618483:Nedd4 protein, human; C000618484:Nedd4 protein, rat; C000618485:Nedd4L protein, human; D044767:Ubiquitin-Protein Ligases
Endocytosis; Hypertension; Protein-Protein Interaction; Sodium-Proton Exchange; Ubiquitin