40 0

Protein kinase B/Akt1 inhibits autophagy by down-regulating UVRAG expression

Title
Protein kinase B/Akt1 inhibits autophagy by down-regulating UVRAG expression
Other Titles
Akt1 inhibits autophagy by down-regulating UVRAG expression
Author
신인철
Keywords
Akt1; Autophagy; LC3B; UVRAG
Issue Date
2013-02
Publisher
Elsevier Science B.V
Citation
Experimental cell research, 2013, 319(3), P.122-133
Abstract
Autophagy, or autophagocytosis, is a selective intracellular degradative process involving the cell's own lysosomal apparatus. An essential component in cell development, homeostasis, repair and resistance to stress, autophagy may result in either cell death or survival. The targeted region of the cell is sequestered within a membrane structure, the autophagosome, for regulation of the catabolic process. A key factor in both autophagosome formation and autophagosome maturation is a protein encoded by the ultraviolet irradiation resistance-associated gene (UVRAG). Conversely, the serine/threonine-specific protein kinase B (PKB, also known as Akt), which regulates survival in various cancers, inhibits autophagy through mTOR activation. We found that Akt1 may also directly inhibit autophagy by down-regulating UVRAG both in a 293T transient transfection system and breast cancer cells stably expressing Akt1. The UVRAG with mutations at putative Akt1-phosphorylation sites were still inhibited by Akt1, and dominant-negative Akt1 also inhibited UVRAG expression, suggesting that Akt1 down-regulates UVRAG by a kinase activity-independent mechanism. We showed that Akt1 overexpression in MDA-MB-231 breast cancer cells down-regulated UVRAG transcription. Cells over-expressing Akt1 were more resistant than control cells to ultraviolet light-induced autophagy and exhibited the associated reduction in cell viability. Levels of the autophagosome indicator protein LC3B-II and mRFP-GFP-LC3 were reduced in cells that over-expressing Akt1. Inhibiting Akt1 by siRNA or reintroducing UVRAG gene rescued the level of LC3B-II in UV-irradiation. Altogether, these data suggest that Akt1 may inhibit autophagy by decreasing UVRAG expression, which also sensitizes cancer cells to UV irradiation.
URI
https://www.sciencedirect.com/science/article/pii/S0014482712004697?via%3Dihub
ISSN
0014-4827
DOI
10.1016/j.yexcr.2012.11.014
Appears in Collections:
COLLEGE OF NATURAL SCIENCES[S](자연과학대학) > LIFE SCIENCE(생명과학과) > Articles
Files in This Item:
There are no files associated with this item.
Export
RIS (EndNote)
XLS (Excel)
XML


qrcode

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

BROWSE