The ubiquitin ligase Nedd4-1 is dispensable for the regulation of PTEN stability and localization.
PTEN is a tumor suppressor frequently mutated in cancer. Recent reports implicated Nedd4-1 as the E3 ubiquitin ligase for PTEN that regulates its stability and nuclear localization. We tested the physiological role of Nedd4-1 as a PTEN regulator by using cells and tissues derived from two independently generated strains of mice with their Nedd4-1 gene disrupted. PTEN stability and ubiquitination were indistinguishable between the wild-type and Nedd4-1-deficient cells, and an interaction between the two proteins could not be detected. Moreover, PTEN subcellular distribution, showing prominent cytoplasmic and nuclear staining, was independent of Nedd4-1 presence. Finally, activation of PKB/Akt, a major downstream target of cytoplasmic PTEN activity, and the ability of PTEN to transactivate the Rad51 promoter, a measure of its nuclear function, were unaffected by the loss of Nedd4-1. Taken together, our results fail to support a role for Nedd4-1 as the E3 ligase regulating PTEN stability and subcellular localization.
Hospital for Sick Children and Biochemistry Department, University of Toronto, MaRS-TMDT, 101 College Street, Toronto, Ontario M5G 1L7, Canada.
Fatemeh
F
Fouladkou
Tamara
T
Landry
Hiroshi
H
Kawabe
Antje
A
Neeb
Chen
C
Lu
Nils
N
Brose
Vuk
V
Stambolic
Daniela
D
Rotin
D000818:Animals; D003593:Cytoplasm / Q000378:metabolism; D056827:Endosomal Sorting Complexes Required for Transport; D051379:Mice; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D000075702:Nedd4 Ubiquitin Protein Ligases; D051059:PTEN Phosphohydrolase / Q000032:analysis* / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051135:Rad51 Recombinase / Q000235:genetics / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*
D056827:Endosomal Sorting Complexes Required for Transport; D000075702:Nedd4 Ubiquitin Protein Ligases; C000618461:Nedd4l protein, mouse; D044767:Ubiquitin-Protein Ligases; D019869:Phosphatidylinositol 3-Kinases; D051135:Rad51 Recombinase; D051059:PTEN Phosphohydrolase; C487757:Pten protein, mouse