Torin1 mediated TOR kinase inhibition reduces Wee1 levels and advances mitotic commitment in fission yeast and HeLa cells

Atkin, Jane; Hálová, Lenka; Ferguson, Jennifer; Hitchin, James R.; Lichawska-Cieslar, Agata; Jordan, Allan M.; Pines, Jonathon; Wellbrock, Claudia; Petersen, Janni

doi:10.1242/jcs.146373

Cited by 38 publications

(99 citation statements)

References 58 publications

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“…This compound is an ATP-competitive inhibitor that impairs the kinase activity of both mTORC1 and mTORC2. The 50% inhibitory concentration of Torin 1 is approximately 10 nM, and concentrations of 100 to 250 nM are typically needed to abolish mTORC1 and mTORC2 activity (16)(17)(18). Importantly, incubation of HeLa cells with Torin 1 at concentrations ranging from 25 to 250 nM reduced the level of entry of a Listeria strain expressing InlB (Fig.…”

Section: Resultsmentioning

confidence: 97%

Host Serine/Threonine Kinases mTOR and Protein Kinase C-α Promote InlB-Mediated Entry of Listeria monocytogenes

et al. 2017

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The bacterial pathogen Listeria monocytogenes causes foodborne illnesses resulting in gastroenteritis, meningitis, or abortion. Listeria induces its internalization into some human cells through interaction of the bacterial surface protein InlB with the host receptor tyrosine kinase Met. InlB-dependent entry requires localized polymerization of the host actin cytoskeleton. The signal transduction pathways that act downstream of Met to regulate actin filament assembly or other processes during Listeria uptake remain incompletely characterized. Here, we demonstrate important roles for the human serine/threonine kinases mTOR and protein kinase C-␣ (PKC-␣) in InlB-dependent entry. Experiments involving RNA interference (RNAi) indicated that two multiprotein complexes containing mTOR, mTORC1 and mTORC2, are each needed for efficient internalization of Listeria into cells of the human cell line HeLa. InlB stimulated Met-dependent phosphorylation of mTORC1 or mTORC2 substrates, demonstrating activation of both mTOR-containing complexes. RNAi studies indicated that the mTORC1 effectors 4E-BP1 and hypoxia-inducible factor 1␣ (HIF-1␣) and the mTORC2 substrate PKC-␣ each control Listeria uptake. Genetic or pharmacological inhibition of PKC-␣ reduced the internalization of Listeria and the accumulation of actin filaments that normally accompanies InlB-mediated entry. Collectively, our results identify mTOR and PKC-␣ to be host factors exploited by Listeria to promote infection. PKC-␣ controls Listeria entry, at least in part, by regulating the actin cytoskeleton downstream of the Met receptor.KEYWORDS InlB, Listeria monocytogenes, Met receptor, protein kinase C, actin, mTOR L isteria monocytogenes is a foodborne pathogen capable of causing serious infections resulting in meningitis or abortions (1). Critical for disease is the ability of Listeria to induce its internalization into nonphagocytic mammalian cells in the intestine, liver, or placenta (2). One of the major pathways of internalization of Listeria into human cells is mediated by interaction of the bacterial surface protein InlB with the host receptor tyrosine kinase Met (3). InlB-dependent entry involves remodeling of the host plasma membrane through actin polymerization (4, 5). Substantial progress in characterizing InlB-mediated uptake has been made, resulting in the identification of several host signal transduction pathways that control actin polymerization and perhaps other physiological processes during entry (4). Despite this progress, a detailed understanding of the molecular mechanism of InlB-dependent internalization of Listeria remains incomplete.The human type IA phosphoinositide 3-kinase (PI3K) pathway is one of the major signaling networks controlling InlB-mediated entry (4,(6)(7)(8). Recent RNA interference (RNAi) screens identified 13 components of the type IA PI3K pathway involved in InlB-dependent internalization of Listeria (9, 10). One host protein demonstrated in this work to play an important role in Listeria entry is mTOR (mammalian ...

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Section: Resultsmentioning

confidence: 97%

Host Serine/Threonine Kinases mTOR and Protein Kinase C-α Promote InlB-Mediated Entry of Listeria monocytogenes

et al. 2017

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“…To further confirm the role of mTOR in MGPC formation, fish were treated with Torin1, a potent inhibitor of both mTORC1 and mTORC2 (Atkin et al, ). As almost all of the INL BrdU+ cells are also GFP+ (Figure b) (Fausett et al, ), the number of INL BrdU+ cells thus represents the number of MGPCs at 4 dpi.…”

Section: Resultsmentioning

confidence: 99%

Inflammation‐induced mammalian target of rapamycin signaling is essential for retina regeneration

Zhang

Hou

et al. 2019

Glia

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Upon retina injury, Müller glia in the zebrafish retina respond by generating multipotent progenitors to repair the retina. However, the complete mechanisms underlying retina regeneration remain elusive. Here we report inflammation‐induced mammalian target of rapamycin (mTOR) signaling in the Müller glia is essential for retina regeneration in adult zebrafish. We show after a stab injury, mTOR is rapidly activated in Müller glia and later Müller glia‐derived progenitor cells (MGPCs). Importantly, mTOR is required for Müller glia dedifferentiation, as well as the proliferation of Müller glia and MGPCs. Interestingly, transient mTOR inhibition by rapamycin only reversibly suppresses MGPC proliferation, while its longer suppression by knocking down Raptor significantly inhibits the regeneration of retinal neurons. We further show mTOR promotes retina regeneration by regulating the mRNA expression of key reprogramming factors ascl1a and lin‐28a, cell cycle‐related genes and critical cytokines. Surprisingly, we identify microglia/macrophage‐mediated inflammation as an important upstream regulator of mTOR in the Müller glia and it promotes retina regeneration through mTOR. Our study not only demonstrates the important functions of mTOR but also reveals an interesting link between inflammation and the mTOR signaling during retina regeneration.

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“…2D). Psk1 phosphorylation was totally absent in the tor2-51 mutant and in control cells treated with the ATP-analogue Torin-1, that targets the kinase domain of mTOR and inhibits the in vivo activity of both TORC1 and TORC2 complexes in fission yeast31 (Suppl. Figure S1).…”

Section: Resultsmentioning

confidence: 99%

Multiple crosstalk between TOR and the cell integrity MAPK signaling pathway in fission yeast

Madrid

Vázquez-Marín

Franco

et al. 2016

Sci Rep

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In eukaryotic cells, the highly conserved Target of Rapamycin (TOR) and the Mitogen Activated Protein Kinase (MAPK) signaling pathways elicit adaptive responses to extra- and intracellular conditions by regulating essential cellular functions. However, the nature of the functional relationships between both pathways is not fully understood. In the fission yeast Schizosaccharomyces pombe the cell integrity MAPK pathway (CIP) regulates morphogenesis, cell wall structure and ionic homeostasis. We show that the Rab GTPase Ryh1, a TORC2 complex activator, cross-activates the CIP and its core member, the MAPK Pmk1, by two distinct mechanisms. The first one involves TORC2 and its downstream effector, Akt ortholog Gad8, which together with TORC1 target Psk1 increase protein levels of the PKC ortholog Pck2 during cell wall stress or glucose starvation. Also, Ryh1 activates Pmk1 in a TORC2-independent fashion by prompting plasma membrane trafficking and stabilization of upstream activators of the MAPK cascade, including PDK ortholog Ksg1 or Rho1 GEF Rgf1. Besides, stress-activated Pmk1 cross-inhibits Ryh1 signaling by decreasing the GTPase activation cycle, and this ensures cell growth during alterations in phosphoinositide metabolism. Our results reveal a highly intricate cross-regulatory relationship between both pathways that warrants adequate cell adaptation and survival in response to environmental changes.

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Torin1 mediated TOR kinase inhibition reduces Wee1 levels and advances mitotic commitment in fission yeast and HeLa cells

Cited by 38 publications

References 58 publications

Host Serine/Threonine Kinases mTOR and Protein Kinase C-α Promote InlB-Mediated Entry of Listeria monocytogenes

Host Serine/Threonine Kinases mTOR and Protein Kinase C-α Promote InlB-Mediated Entry of Listeria monocytogenes

Inflammation‐induced mammalian target of rapamycin signaling is essential for retina regeneration

Multiple crosstalk between TOR and the cell integrity MAPK signaling pathway in fission yeast

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