Differential expression and localisation of WWP1, a Nedd4-like protein, in epithelia.
Ubiquitination of proteins such as ion transporters appears to be an important process in the regulation of their membrane expression. Recently, using two-hybrid screening, we have selected a potential partner for the alpha-subunit of the amiloride-sensitive epithelial sodium channel (ENaC): the WWP1 protein, a ubiquitin ligase belonging to the Nedd4 family. To establish whether WWP1 is co-expressed with ENaC, we employed in situ hybridisation, immunohistochemistry and Western blotting to determine the expression of WWP1 in various tissues and cell lines, including those known to express ENaC. As expected, WWP1 was expressed, like ENaC, in the bronchiolar epithelium. However it was also present in the proximal colon and the proximal part of the nephron (where ENaC is not expressed) and absent in the distal parts of the nephron (where ENaC is expressed abundantly). These results suggest that other channels or transport proteins, containing specific domains, such as PY motifs, could be the targets for regulation by WWP1.
Malbert-Colas
Laurence
L
INSERM Unité 409, Faculté de Médecine X. Bichat, BP416, 75870 Paris Cedex 18, France.
Fay
Michel
M
Cluzeaud
Françoise
F
Blot-Chabaud
Marcel
M
Farman
Nicolette
N
Dhermy
Didier
D
Lecomte
Marie-Christine
MC
D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002460:Cell Line; D002522:Chlorocebus aethiops; D056827:Endosomal Sorting Complexes Required for Transport; D004847:Epithelial Cells / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D018374:LLC-PK1 Cells; D008297:Male; D008969:Molecular Sequence Data; D000075702:Nedd4 Ubiquitin Protein Ligases; D051381:Rats; D017207:Rats, Sprague-Dawley; D013552:Swine; D044767:Ubiquitin-Protein Ligases / Q000096:biosynthesis* / Q000235:genetics; D014981:Xenopus; D029867:Xenopus Proteins
D056827:Endosomal Sorting Complexes Required for Transport; D029867:Xenopus Proteins; C000618479:NEDD4L protein, rat; D000075702:Nedd4 Ubiquitin Protein Ligases; C000618482:Nedd4 protein, Xenopus; C000618483:Nedd4 protein, human; C000618484:Nedd4 protein, rat; C471642:WWP1 protein, human; C000618460:nedd4l protein, Xenopus; D044767:Ubiquitin-Protein Ligases