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Over‐expression of ATR causes autophagic cell death
Author(s) -
Mori Chihiro,
Yamaguchi Yoshihiro,
Teranishi Mika,
Takanami Takako,
Nagase Takahiro,
Kanno Shinichiro,
Yasui Akira,
Higashitani Atsushi
Publication year - 2013
Publication title -
genes to cells
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.912
H-Index - 115
eISSN - 1365-2443
pISSN - 1356-9597
DOI - 10.1111/gtc.12034
Subject(s) - vacuolization , biology , microbiology and biotechnology , autophagy , programmed cell death , kinase , viability assay , cell , biochemistry , apoptosis , endocrinology
ATR is highly conserved in all eukaryotes and functions as a cell‐cycle checkpoint kinase to stabilize the nuclear genome. In addition, knockout mouse models indicate that ATR is essential for viability. Here, it is shown that moderate overproduction of ATR , but not of the other phosphatidylinositol 3′ kinase‐related kinases, ataxia‐telangiectasia‐mutated, m TOR and SMG ‐1, and a downstream target p53, resulted in cell death. ATR over‐expression induced cellular vacuolization from 12 to 48 h after transfection, before cell death progression. A series of deletion analyses showed that overproduction of the N ‐terminal HEAT repeat segments of ATR was sufficient for the induction of the vacuolization. Moreover, post‐transcriptional modification of LC 3, a marker of autophagy, and autophagosomes with double membranes were evident in ATR ‐overproducing cells. The vacuolization was also suppressed in autophagy‐deficient MCF 7 cells. In addition, both cellular vacuolization and cell death were reduced by inhibition of R as activity using farnesyl thiosalicylic acid. Conversely, neither inhibition of m TOR nor activation of the checkpoint system could be observed in the vacuolated cells. These results suggest that the R as signaling pathway is involved in the autophagic response caused by ATR overproduction, and tight regulation of ATR protein expression is crucial for cell viability.