Akt activation increases cellular cholesterol by promoting the proteasomal degradation of Niemann-Pick C1

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningfagfællebedømt

  • Ximing Du
  • Yuxi Zhang
  • Sae Rom Jo
  • Xiaoyun Liu
  • Yanfei Qi
  • Osborne, Brenna
  • Frances L. Byrne
  • Greg C. Smith
  • Nigel Turner
  • Kyle L. Hoehn
  • Andrew J. Brown
  • Hongyuan Yang

Null mutations of the Niemann-Pick type C1 (NPC1) gene cause NPC disease, a lysosomal storage disorder characterized by cholesterol accumulation in late endosomes (LE) and lysosomes (Ly).Nascent ormutated NPC1 is degraded through the ubiquitin-proteasome pathway, but how NPC1 degradation is regulated remains currently unknown. In the present study, we demonstrated a link between NPC1 degradation and the Akt (protein kinase B)/mTOR [mammalian (or mechanistic) target of rapamycin] signalling pathway in cervical cancer cell lines. We provided evidence that activated Akt/mTOR pathway increased NPC1 degradation by ∼50% in C33A cells when compared with SiHa or HeLa cells. NPC1 degradation in C33A cells was reversed when Akt/mTOR activation was blocked by specific inhibitors or when mTORC1 (mTOR complex 1) was disrupted by regulatory associated protein of mTOR (Raptor) knockdown. Importantly, inhibition of the Akt/mTOR pathway led to decreased NPC1 ubiquitination in C33A cells, pointing to a role of Akt/mTOR in the proteasomal degradation of NPC1. Moreover, we found that NPC1 depletion in several cancer cell lines inhibited cell proliferation and migration. Our results uncover Akt as a key regulator of NPC1 degradation and link NPC1 to cancer cell proliferation and migration.

OriginalsprogEngelsk
TidsskriftBiochemical Journal
Vol/bind471
Udgave nummer2
Sider (fra-til)243-253
Antal sider11
ISSN0264-6021
DOI
StatusUdgivet - 15 okt. 2015

Bibliografisk note

Publisher Copyright:
© 2015 Authors; published by Portland Press Limited.

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