Ndfip1 regulates nuclear Pten import in vivo to promote neuronal survival following cerebral ischemia.
PTEN (phosphatase and tensin homologue deleted on chromosome TEN) is the major negative regulator of phosphatidylinositol 3-kinase signaling and has cell-specific functions including tumor suppression. Nuclear localization of PTEN is vital for tumor suppression; however, outside of cancer, the molecular and physiological events driving PTEN nuclear entry are unknown. In this paper, we demonstrate that cytoplasmic Pten was translocated into the nuclei of neurons after cerebral ischemia in mice. Critically, this transport event was dependent on a surge in the Nedd4 family-interacting protein 1 (Ndfip1), as neurons in Ndfip1-deficient mice failed to import Pten. Ndfip1 binds to Pten, resulting in enhanced ubiquitination by Nedd4 E3 ubiquitin ligases. In vitro, Ndfip1 overexpression increased the rate of Pten nuclear import detected by photobleaching experiments, whereas Ndfip1(-/-) fibroblasts showed negligible transport rates. In vivo, Ndfip1 mutant mice suffered larger infarct sizes associated with suppressed phosphorylated Akt activation. Our findings provide the first physiological example of when and why transient shuttling of nuclear Pten occurs and how this process is critical for neuron survival.
Brain Development and Regeneration Laboratory, Florey Neuroscience Institutes, The University of Melbourne, Parkville, Victoria 3010, Australia.
Jason
J
Howitt
Jenny
J
Lackovic
Ley-Hian
LH
Low
Adam
A
Naguib
Alison
A
Macintyre
Choo-Peng
CP
Goh
Jennifer K
JK
Callaway
Vicki
V
Hammond
Tim
T
Thomas
Matthew
M
Dixon
Ulrich
U
Putz
John
J
Silke
Perry
P
Bartlett
Baoli
B
Yang
Sharad
S
Kumar
Lloyd C
LC
Trotman
Seong-Seng
SS
Tan
D000818:Animals; D002545:Brain Ischemia / Q000378:metabolism* / Q000473:pathology; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D002470:Cell Survival; D056827:Endosomal Sorting Complexes Required for Transport / Q000502:physiology; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D000075702:Nedd4 Ubiquitin Protein Ligases; D009474:Neurons / Q000502:physiology*; D051059:PTEN Phosphohydrolase / Q000378:metabolism*; D038761:Photobleaching; D021381:Protein Transport; D044767:Ubiquitin-Protein Ligases / Q000502:physiology; D054875:Ubiquitination
D002352:Carrier Proteins; D056827:Endosomal Sorting Complexes Required for Transport; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C499188:Ndfip1 protein, mouse; D000075702:Nedd4 Ubiquitin Protein Ligases; C000618461:Nedd4l protein, mouse; D044767:Ubiquitin-Protein Ligases; D051059:PTEN Phosphohydrolase; C487757:Pten protein, mouse