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Osmotic Stress Regulates Mammalian Target of Rapamycin (mTOR) Complex 1 via c-Jun N-terminal Kinase (JNK)-mediated Raptor Protein Phosphorylation.

Authors :
Dongoh Kwak
Sunkyu Choi
Heeyoon Jeong
Jin-Hyeok Jang
Youngmi Lee
Hyeona Jeon
Mi Nam Lee
Jungeun Noh
Kun Cho
Jong Shin Yoo
Daehee Hwang
Pann-Ghill Suh
Sung Ho Ryu
Source :
Journal of Biological Chemistry. 5/25/2012, Vol. 287 Issue 22, p18398-18407. 10p.
Publication Year :
2012

Abstract

mTOR complex 1 (mTORC1) is a multiprotein complex that integrates diverse signals including growth factors, nutrients, and stress to control cell growth. Raptor is an essential component of mTORC1 that functions to recruit specific substrates. Recently, Raptor was suggested to be a key target of regulation of mTORC1. Here, we show that Raptor is phosphorylated by JNK upon osmotic stress. We identified that osmotic stress induces the phosphorylation of Raptor at Ser-696, Thr-706, and Ser-863 using liquid chromatography-tandem mass spectrometry. We found that JNK is responsible for the phosphorylation. The inhibition of JNK abolishes the phosphorylation of Raptor induced by osmotic stress in cells. Furthermore, JNK physically associates with Raptor and phosphorylates Raptor in vitro, implying that JNK is responsible for the phosphorylation of Raptor. Finally, we found that osmotic stress activates mTORC1 kinase activity in a JNK-dependent manner. Our findings suggest that the molecular link between JNK and Raptor is a potential mechanism by which stress regulates the mTORC1 signaling pathway. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00219258
Volume :
287
Issue :
22
Database :
Academic Search Index
Journal :
Journal of Biological Chemistry
Publication Type :
Academic Journal
Accession number :
76568149
Full Text :
https://doi.org/10.1074/jbc.M111.326538