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Alkaline stress‐induced autophagy is mediated by mTORC1 inactivation
Author(s) -
Suk Jinkyu,
Kwak Sang Su,
Lee Jae Ho,
Choi Ji Hye,
Lee SangHee,
Lee Dong Hwan,
Byun Boohyeong,
Lee GeonHyoung,
Joe Cheol O.
Publication year - 2011
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/jcb.23181
Subject(s) - autophagy , microbiology and biotechnology , mtorc1 , chemistry , lysosome , cytosol , activator (genetics) , vacuole , biochemistry , biology , signal transduction , enzyme , cytoplasm , pi3k/akt/mtor pathway , gene , apoptosis
The activation of autophagic pathway by alkaline stress was investigated. Various types of mammalian cells were subjected to alkaline stress by incubation in bicarbonate buffered media in humidified air containing atmospheric 0.04% CO 2 . The induction of autophagy following alkaline stress was evaluated by assessing the conversion of cytosolic LC3‐I into lipidated LC3‐II, the accumulation of autophagosomes, and the formation of autolysosomes. Colocalization of GFP‐LC3 with endolysosomal marker in HeLa GFP‐LC3 cells undergoing autophagic process by alkaline stress further demonstrates that autophagosomes triggered by alkaline stress matures into autolysosomes for the lysosome dependent degradation. We found that the inactivation of mTORC1 is important for the pathway leading to the induction of autophagy by alkaline stress since the expression of RhebQ64L, a constitutive activator of mTORC1, downregulates the induction of autophagy after alkaline stress in transfected human 293T cells. These results imply that activation of autophagic pathway following the inactivation of mTORC1 is important cellular events governing alkaline stress‐induced cytotoxicity and clinical symptoms associated with alkalosis. J. Cell. Biochem. 112: 2566–2573, 2011. © 2011 Wiley‐Liss, Inc.