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Identification of an AMPK Phosphorylation Site in Drosophila TSC2 (gigas) that Regulate Cell Growth

AMP-activated protein kinase (AMPK) is an important metabolic regulator that mediates cellular adaptation to diverse stresses. One of the AMPK substrates, tuberous sclerosis complex 2 (TSC2), was suggested to mediate AMPK-induced silencing of mTOR complex 1 (mTORC1) signaling that is critical for ce...

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Autores principales: Kim, Myungjin, Lee, Jun Hee
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2015
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4425001/
https://www.ncbi.nlm.nih.gov/pubmed/25826530
http://dx.doi.org/10.3390/ijms16047015
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author Kim, Myungjin
Lee, Jun Hee
author_facet Kim, Myungjin
Lee, Jun Hee
author_sort Kim, Myungjin
collection PubMed
description AMP-activated protein kinase (AMPK) is an important metabolic regulator that mediates cellular adaptation to diverse stresses. One of the AMPK substrates, tuberous sclerosis complex 2 (TSC2), was suggested to mediate AMPK-induced silencing of mTOR complex 1 (mTORC1) signaling that is critical for cell growth. However, it is not known whether the AMPK-dependent TSC2 phosphorylation, originally observed in mammalian cells, is conserved in invertebrates. Here we show that energy depletion inhibits mTORC1 signaling through the AMPK-TSC2 axis in Drosophila S2 cells. We have discovered an AMPK phosphorylation site in TSC2-like genes from many different invertebrate species including Drosophila. The site (Ser1338 in Drosophila TSC2) is specifically and efficiently phosphorylated by AMPK in vitro. To evaluate the functional role of this phosphorylation site in vivo, we generated transgenic flies that can express identical amount of either wild-type or phosphorylation-resistant mutant Drosophila TSC2 in a tissue-specific manner. In response to transgenic Sestrin induction, which causes ectopic AMPK activation and subsequent mTORC1 inhibition, wild-type Drosophila TSC2 synergistically reduced tissue growth in the dorsal epithelium of Drosophila wings. However, phosphorylation-resistant mutant Drosophila TSC2 was unable to show such a growth-inhibiting effect, suggesting that this phosphorylation is important for AMPK-dependent regulation of cell growth.
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spelling pubmed-44250012015-05-20 Identification of an AMPK Phosphorylation Site in Drosophila TSC2 (gigas) that Regulate Cell Growth Kim, Myungjin Lee, Jun Hee Int J Mol Sci Communication AMP-activated protein kinase (AMPK) is an important metabolic regulator that mediates cellular adaptation to diverse stresses. One of the AMPK substrates, tuberous sclerosis complex 2 (TSC2), was suggested to mediate AMPK-induced silencing of mTOR complex 1 (mTORC1) signaling that is critical for cell growth. However, it is not known whether the AMPK-dependent TSC2 phosphorylation, originally observed in mammalian cells, is conserved in invertebrates. Here we show that energy depletion inhibits mTORC1 signaling through the AMPK-TSC2 axis in Drosophila S2 cells. We have discovered an AMPK phosphorylation site in TSC2-like genes from many different invertebrate species including Drosophila. The site (Ser1338 in Drosophila TSC2) is specifically and efficiently phosphorylated by AMPK in vitro. To evaluate the functional role of this phosphorylation site in vivo, we generated transgenic flies that can express identical amount of either wild-type or phosphorylation-resistant mutant Drosophila TSC2 in a tissue-specific manner. In response to transgenic Sestrin induction, which causes ectopic AMPK activation and subsequent mTORC1 inhibition, wild-type Drosophila TSC2 synergistically reduced tissue growth in the dorsal epithelium of Drosophila wings. However, phosphorylation-resistant mutant Drosophila TSC2 was unable to show such a growth-inhibiting effect, suggesting that this phosphorylation is important for AMPK-dependent regulation of cell growth. MDPI 2015-03-27 /pmc/articles/PMC4425001/ /pubmed/25826530 http://dx.doi.org/10.3390/ijms16047015 Text en © 2015 by the authors; licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Communication
Kim, Myungjin
Lee, Jun Hee
Identification of an AMPK Phosphorylation Site in Drosophila TSC2 (gigas) that Regulate Cell Growth
title Identification of an AMPK Phosphorylation Site in Drosophila TSC2 (gigas) that Regulate Cell Growth
title_full Identification of an AMPK Phosphorylation Site in Drosophila TSC2 (gigas) that Regulate Cell Growth
title_fullStr Identification of an AMPK Phosphorylation Site in Drosophila TSC2 (gigas) that Regulate Cell Growth
title_full_unstemmed Identification of an AMPK Phosphorylation Site in Drosophila TSC2 (gigas) that Regulate Cell Growth
title_short Identification of an AMPK Phosphorylation Site in Drosophila TSC2 (gigas) that Regulate Cell Growth
title_sort identification of an ampk phosphorylation site in drosophila tsc2 (gigas) that regulate cell growth
topic Communication
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4425001/
https://www.ncbi.nlm.nih.gov/pubmed/25826530
http://dx.doi.org/10.3390/ijms16047015
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AT leejunhee identificationofanampkphosphorylationsiteindrosophilatsc2gigasthatregulatecellgrowth