MTORC1/AMPK responses define a core gene set for developmental cell fate switching
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ABSTRACT:
PROVIDER: PRJNA509345 | ENA |
REPOSITORIES: ENA
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Project description:The kinases mTORC1 and AMPK are at the nexus of nutrient responses and control of cellular growth. However, responses to nutrient loss are complex and affect multiple transcriptional pathways. We are interested in the mTORC1-directed regulation of transcription networks that specifically regulate developmental decisions. Dictyostelium grow logarithmically as single cells in nutrient-rich media, but, upon nutrient withdrawal, growth ceases and cells enter a program for multi-cellular development. Within 30 minutes of starvation, >4,000 genes show significant (p<0.05) changes in gene expression patterns. However, we hypothesize that not all these gene changes are required for development and that many expression changes reflect stress response to a media shift supplementary to nutrient loss, apart from developmental effects. We, thus, sought ways to promote development in the absence of nutrient loss, to better focus on developmentally essential gene sets. Since kinases mTORC1 and AMPK function as nutrient and energy sensors, we first examined their relative activities in Dictyostelium during phases of rapid growth and starvation-induced development. We found that these kinases exhibited reciprocal patterns of activation under various conditions. With this knowledge, we identified rich media conditions that permitted rapid cell growth, but a growth/development switch upon the directed and reciprocal inactivation/activation of mTORC1/AMPK. Examination of gene expression under conditions of development in nutrient-rich media indicated that changes in expression of most starvation-regulated genes were not required for development. Our data suggest that the up-regulation of ~300 genes defines essential early signaling pathways for developmental induction, integrating cAMP/PKA circuitries and including many unclassified genes.
2019-05-22 | GSE123599 | GEO
Project description: Not available
| S-EPMC6637605 | biostudies-literature
Project description:Pancreatic beta cells (β-cells) differentiate during fetal life, but only postnatally acquire the capacity for glucose-stimulated insulin secretion (GSIS). The molecular mechanisms driving this maturation of β-cell function remain incompletely understood. Here, we show that the control of cellular signaling in β-cells fundamentally switches from the nutrient sensor target of rapamycin (mTORC1) to the energy sensor 5'-adenosine monophosphate-activated protein kinase (AMPK), and that this is critical for functional maturation. Moreover, AMPK is activated by the dietary transition taking place during weaning, and this in turn inhibits mTORC1 activity to drive the adult β-cell phenotype. While forcing constitutive mTORC1 signaling in adult β-cells relegates them to a functionally immature phenotype with characteristic transcriptional and metabolic profiles, engineering the switch from mTORC1 to AMPK signaling is sufficient to promote β-cell mitochondrial biogenesis, a shift to oxidative metabolism, and functional maturation. We also show that type 2 diabetes, a condition marked by both mitochondrial degeneration and dysregulated GSIS, is associated with a remarkable reversion of the normal AMPK-dependent adult β-cell signature to a more neonatal one characterized by mTORC1 activation. Manipulating the way in which cellular nutrient signaling pathways regulate β-cell metabolism may thus offer new targets to improve β-cell function in diabetes.
2019-06-06 | GSE132261 | GEO
Project description:mTORC1 to AMPK Switching Underlies β-Cell Metabolic Plasticity During Maturation and Diabetes
| PRJNA547067 | ENA
Project description:AMPK activation by GSK621 induces cell death in acute myeloid leukemia. Surprisingly, we found that mTORC1 inhibition with rapamycin protects cells against GSK621-induced cytotoxicity. A genome-wide gene expression assay was performed to understand the molecular basis of this phenotype.
2016-04-22 | GSE68209 | GEO
Project description:Sonntag2012 - mTOR model - IRS dependent regulation of AMPK by insulin
TSC1-TSC2 complex has two states: 1)
active (TSC1_TSC2_pS1387), regulated by AMPK_pT172; 2) inactive
(TSC1_TSC2_pT1462) regulated by Akt_pT308. Particularly, mTORC1 is
inhibited by TSC1_TSC2 in active state. AMPK is activated at T172
by the species IRS1_p activated by the insulin receptor upon
insulin stimulation. Consequently, AMPK_pT172 is inhibited by
mTORC1_pS2448 indirectly by the p70-S6K-negative feedback loop.
This model is described in the article:
A modelling-experimental
approach reveals insulin receptor substrate (IRS)-dependent
regulation of adenosine monosphosphate-dependent kinase (AMPK)
by insulin.
Sonntag AG, Dalle Pezze P, Shanley
DP, Thedieck K.
FEBS J. 2012 Sep; 279(18):
3314-3328
Abstract:
Mammalian target of rapamycin (mTOR) kinase responds to
growth factors, nutrients and cellular energy status and is a
central controller of cellular growth. mTOR exists in two
multiprotein complexes that are embedded into a complex
signalling network. Adenosine monophosphate-dependent kinase
(AMPK) is activated by energy deprivation and shuts off
adenosine 5'-triphosphate (ATP)-consuming anabolic processes,
in part via the inactivation of mTORC1. Surprisingly, we
observed that AMPK not only responds to energy deprivation but
can also be activated by insulin, and is further induced in
mTORC1-deficient cells. We have recently modelled the mTOR
network, covering both mTOR complexes and their insulin and
nutrient inputs. In the present study we extended the network
by an AMPK module to generate the to date most comprehensive
data-driven dynamic AMPK-mTOR network model. In order to define
the intersection via which AMPK is activated by the insulin
network, we compared simulations for six different hypothetical
model structures to our observed AMPK dynamics. Hypotheses
ranking suggested that the most probable intersection between
insulin and AMPK was the insulin receptor substrate (IRS) and
that the effects of canonical IRS downstream cues on AMPK would
be mediated via an mTORC1-driven negative-feedback loop. We
tested these predictions experimentally in multiple set-ups,
where we inhibited or induced players along the insulin-mTORC1
signalling axis and observed AMPK induction or inhibition. We
confirmed the identified model and therefore report a novel
connection within the insulin-mTOR-AMPK network: we conclude
that AMPK is positively regulated by IRS and can be inhibited
via the negative-feedback loop.
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2015-08-12 | BIOMD0000000580 | BioModels
Project description:Despite being the frontline therapy for Type 2 diabetes, the mechanisms of action of the biguanide drug metformin are still being discovered. In particular, the detailed molecular interplays between the AMPK and the mTORC1 pathway in the hepatic benefits of metformin are still ill-defined. Metformin-dependent activation of AMPK classically inhibits mTORC1 via TSC/RHEB. But several lines of evidence suggest additional mechanisms at play in metformin inhibition of mTORC1. Here we investigated the role of direct AMPK-mediated serine phosphorylation of RAPTOR in a new RaptorAA mouse model, in which AMPK phospho-serine sites Ser722 and Ser792 of RAPTOR were mutated to alanine. Metformin treatment of primary hepatocytes and intact murine liver requires AMPK regulation of both RAPTOR and TSC2 to fully inhibit mTORC1, and this regulation is critical for the transcriptional response to metformin. Transcriptionally, AMPK and mTORC1 were both important for regulation of anabolic metabolism and inflammatory programs triggered by metformin treatment.
2023-08-10 | GSE157048 | GEO
Project description:Despite being the frontline therapy for Type 2 diabetes, the mechanisms of action of the biguanide drug metformin are still being discovered. In particular, the detailed molecular interplays between the AMPK and the mTORC1 pathway in the hepatic benefits of metformin are still ill-defined. Metformin-dependent activation of AMPK classically inhibits mTORC1 via TSC/RHEB. But several lines of evidence suggest additional mechanisms at play in metformin inhibition of mTORC1. Here we investigated the role of direct AMPK-mediated serine phosphorylation of RAPTOR in a new RaptorAA mouse model, in which AMPK phospho-serine sites Ser722 and Ser792 of RAPTOR were mutated to alanine. Metformin treatment of intact murine liver requires AMPK regulation of both RAPTOR and TSC2 to fully inhibit mTORC1, and this regulation is critical for the transcriptional response to metformin. Transcriptionally, AMPK and mTORC1 were both important for regulation of anabolic metabolism and inflammatory programs triggered by metformin treatment. The hepatic transcriptional response in mice on high fat diet treated with metformin was largely ablated by AMPK-deficiency under the conditions examined, indicating the essential role of this kinase and its targets in metformin action in vivo.
2023-08-10 | GSE157049 | GEO
Project description:Despite being the frontline therapy for Type 2 diabetes, the mechanisms of action of the biguanide drug metformin are still being discovered. In particular, the detailed molecular interplays between the AMPK and the mTORC1 pathway in the hepatic benefits of metformin are still ill-defined. Metformin-dependent activation of AMPK classically inhibits mTORC1 via TSC/RHEB. But several lines of evidence suggest additional mechanisms at play in metformin inhibition of mTORC1. Here we investigated the role of direct AMPK-mediated serine phosphorylation of RAPTOR in a new RaptorAA mouse model, in which AMPK phospho-serine sites Ser722 and Ser792 of RAPTOR were mutated to alanine. Metformin treatment of primary hepatocytes and intact murine liver requires AMPK regulation of both RAPTOR and TSC2 to fully inhibit mTORC1, and this regulation is critical for the translational response to metformin.
2023-08-10 | GSE157050 | GEO
Project description:Amino acids (aa) are not only building blocks for proteins, but also signalling molecules, with the mammalian target of rapamycin complex 1 (mTORC1) acting as a key mediator. However, little is known about whether aa, independently of mTORC1, activate other kinases of the mTOR signalling network. To delineate aa-stimulated mTOR network dynamics, we here combine a computational–experimental approach with text mining-enhanced quantitative proteomics. We report that AMP-activated protein kinase (AMPK), phosphatidylinositide 3-kinase (PI3K) and mTOR complex 2 (mTORC2) are acutely activated by aa-readdition in an mTORC1-independent manner. AMPK activation by aa is mediated by Ca2+/calmodulin-dependent protein kinase kinase β (CaMKKβ). In response, AMPK impinges on the autophagy regulators Unc-51-like kinase-1 (ULK1) and c-Jun. AMPK is widely recognized as an mTORC1 antagonist that is activated by starvation. We find that aa acutely activate AMPK concurrently with mTOR. We show that AMPK under aa sufficiency acts to sustain autophagy. This may be required to maintain protein homoeostasis and deliver metabolite intermediates for biosynthetic processes.
2016-12-12 | PXD003073 | Pride