Dataset Information

A cell cycle kinase-phosphatase module restrains PI3K- Akt activity in an mTORC1-dependent manner

ABSTRACT: The AKT-mTOR pathway is a central regulator of cell growth and metabolism. Upon sustained mTOR activity, AKT activity is attenuated by a feedback loop that restrains upstream signaling. However, how cells control the signals that limit AKT activity is not fully understood. Here we show that MASTL/Greatwall, a cell-cycle kinase that supports mitosis by phosphorylating the PP2A/B55 inhibitors ENSA/ARPP19, inhibits PI3K-AKT activity by sustaining mTORC1- and S6K1-dependent phosphorylation of IRS1 and GRB10. Genetic depletion of MASTL results in an inefficient feedback loop and AKT hyperactivity. These defects are rescued by expression of phospho-mimetic ENSA/ARPP19 or inhibition of PP2A/B55 phosphatases. MASTL is directly phosphorylated by mTORC1, thereby limiting the PP2A/B55-dependent dephosphorylation of IRS1 and GRB10 downstream of mTORC1. Downregulation of MASTL results in increased glucose uptake in vitro and increased glucose tolerance in adult mice, suggesting the relevance of the MASTL-PP2A/B55 kinase-phosphatase module in controlling AKT and maintaining metabolic homeostasis.

INSTRUMENT(S): LTQ Orbitrap Velos, maXis

ORGANISM(S): Homo Sapiens (human) Mus Musculus (mouse)

TISSUE(S): Embryonic Stem Cell

SUBMITTER: Pilar Ximenez-Embun

LAB HEAD: Javier Muñoz Peralta

PROVIDER: PXD032796 | Pride | 2022-11-23

REPOSITORIES: Pride

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Publications

The MASTL/PP2A cell cycle kinase-phosphatase module restrains PI3K-Akt activity in an mTORC1-dependent manner.

Sanz-Castillo Belén B Hurtado Begoña B Vara-Ciruelos Diana D El Bakkali Aicha A Hermida Dario D Salvador-Barbero Beatriz B Martínez-Alonso Diego D González-Martínez José J Santiveri Clara C Campos-Olivas Ramón R Ximénez-Embún Pilar P Muñoz Javier J Álvarez-Fernández Mónica M Malumbres Marcos M

The EMBO journal 20221110 2

The AKT-mTOR pathway is a central regulator of cell growth and metabolism. Upon sustained mTOR activity, AKT activity is attenuated by a feedback loop that restrains upstream signaling. However, how cells control the signals that limit AKT activity is not fully understood. Here, we show that MASTL/Greatwall, a cell cycle kinase that supports mitosis by phosphorylating the PP2A/B55 inhibitors ENSA/ARPP19, inhibits PI3K-AKT activity by sustaining mTORC1- and S6K1-dependent phosphorylation of IRS1 ...[more]

PMID: 36354735

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Project description:DallePezze2012 - TSC-independent mTORC2 regulation This model is described in the article: A dynamic network model of mTOR signaling reveals TSC-independent mTORC2 regulation. Dalle Pezze P, Sonntag AG, Thien A, Prentzell MT, Gödel M, Fischer S, Neumann-Haefelin E, Huber TB, Baumeister R, Shanley DP, Thedieck K. Sci Signal 2012 Mar; 5(217): ra25 Abstract: The kinase mammalian target of rapamycin (mTOR) exists in two multiprotein complexes (mTORC1 and mTORC2) and is a central regulator of growth and metabolism. Insulin activation of mTORC1, mediated by phosphoinositide 3-kinase (PI3K), Akt, and the inhibitory tuberous sclerosis complex 1/2 (TSC1-TSC2), initiates a negative feedback loop that ultimately inhibits PI3K. We present a data-driven dynamic insulin-mTOR network model that integrates the entire core network and used this model to investigate the less well understood mechanisms by which insulin regulates mTORC2. By analyzing the effects of perturbations targeting several levels within the network in silico and experimentally, we found that, in contrast to current hypotheses, the TSC1-TSC2 complex was not a direct or indirect (acting through the negative feedback loop) regulator of mTORC2. Although mTORC2 activation required active PI3K, this was not affected by the negative feedback loop. Therefore, we propose an mTORC2 activation pathway through a PI3K variant that is insensitive to the negative feedback loop that regulates mTORC1. This putative pathway predicts that mTORC2 would be refractory to Akt, which inhibits TSC1-TSC2, and, indeed, we found that mTORC2 was insensitive to constitutive Akt activation in several cell types. Our results suggest that a previously unknown network structure connects mTORC2 to its upstream cues and clarifies which molecular connectors contribute to mTORC2 activation. This model is hosted on BioModels Database and identified by: BIOMD0000000581. To cite BioModels Database, please use: BioModels Database: An enhanced, curated and annotated resource for published quantitative kinetic models. To the extent possible under law, all copyright and related or neighbouring rights to this encoded model have been dedicated to the public domain worldwide. Please refer to CC0 Public Domain Dedication for more information.

Dataset Information

A cell cycle kinase-phosphatase module restrains PI3K- Akt activity in an mTORC1-dependent manner

Publications

The MASTL/PP2A cell cycle kinase-phosphatase module restrains PI3K-Akt activity in an mTORC1-dependent manner.

Similar Datasets

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