Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

ArfGAP1 inhibits mTORC1 lysosomal localization and activation

ABSTRACT: The mammalian target of rapamycin complex 1 (mTORC1) integrates nutrients, growth factors, stress, and energy status to regulate cell growth and metabolism. Amino acids promote mTORC1 lysosomal localization and subsequent activation. However, the subcellular location or interacting proteins of mTORC1 under amino acid deficient conditions is not completely understood. Here, we identify ADP-ribosylation factor GTPase-activating protein 1 (ArfGAP1) as a crucial regulator of mTORC1. ArfGAP1 interacts with mTORC1 in the absence of amino acids and inhibits mTORC1 lysosomal localization and activation. Mechanistically, the membrane curvature sensing amphipathic lipid packing sensor (ALPS) motifs that bind to vesicle membranes, are crucial for ArfGAP1 to interact with and regulate mTORC1 activity. Importantly, ArfGAP1 represses cell growth through mTORC1 and is an independent prognostic factor for the overall survival of pancreatic cancer patients. Our study identifies ArfGAP1 as a critical regulator of mTORC1 that functions by preventing the lysosomal transport and activation of mTORC1, with potential for cancer therapeutics.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Cell Culture

SUBMITTER: Delong Meng

LAB HEAD: Jenna Lee Jewell

PROVIDER: PXD024603 | Pride | 2021-04-01

REPOSITORIES: Pride

ACCESS DATA

Json Xml

Dataset's files

Source:

			Action	DRS
	132_EV_NC_F027948_Cutoff40.xlsx	Xlsx
	132_Empty_Vector.raw	Raw
	136_FlagRaptor_NC_F027942_Cutoff40.xlsx	Xlsx
	136_Flag_Raptor.raw	Raw

Items per page:

1 - 4 of 4

Similar Datasets

Architecture of human Rag GTPase heterodimers and their complex with mTORC1

Project description:The Rag GTPases recruit the master kinase mTORC1 to lysosomes to regulate cell growth and proliferation in response to amino acid availability. The nucleotide state of Rag heterodimers is critical for their association with mTORC1. Our cryo-EM structure of RagA/RagC in complex with mTORC1 shows the details of RagA/C binding to the RAPTOR subunit of mTORC1 and explains why only the RagAGTP/RagCGDP nucleotide state binds mTORC1. Previous kinetic studies suggested that GTP binding to one Rag locks the heterodimer to prevent GTP binding to the other. Our crystal structures and dynamics show the mechanism for this locking, and explain how oncogenic hotspot mutations disrupt this process. In contrast to allosteric activation by RHEB, Rag heterodimer binding does not change mTORC1 conformation and activates mTORC1 by targeting it to lysosomes.

2019-10-11 | PXD015778 | Pride

mTORC1 maintains renal tubular homeostasis and is essential in response to ischemic stress

Project description:The mechanistic target of rapamycin mTORC1 is a key regulator of cell metabolism and autophagy. Despite widespread clinical use of mTOR inhibitors, the role of mTORC1 in renal tubular function and kidney homeostasis remains elusive. By utilizing constitutive and inducible deletion of conditional Raptor alleles in renal tubular epithelial cells, we discovered that mTORC1 deficiency caused a marked concentrating defect, loss of tubular cells and slowly progressive renal fibrosis. Transcriptional profiling revealed that mTORC1 maintains renal tubular homeostasis by controlling mitochondrial metabolism and biogenesis as well as transcellular transport processes involved in counter-current multiplication and urine concentration. Although mTORC2 partially compensated the loss of mTORC1, exposure to ischemia and reperfusion injury exaggerated the tubular damage in mTORC1-deficient mice, and caused pronounced apoptosis, diminished proliferation rates and delayed recovery. These findings identify mTORC1 as an essential regulator of tubular energy metabolism and as a crucial component of ischemic stress responses. Pharmacological inhibition of mTORC1 likely affects tubular homeostasis, and may be particularly deleterious if the kidney is exposed to acute injury. Furthermore, the combined inhibition of mTORC1 and mTORC2 may increase the susceptibility to renal damage. Raptor fl/fl*KspCre and Raptor fl/fl animals were sacrificed at P14 before the development of an overt functional phenotype. Kidneys were split in half and immediately snap frozen in liquid nitrogen.

2014-06-09 | E-GEOD-54417 | biostudies-arrayexpress

An mTORC1-mediated negative feedback loop constrains amino acid-induced FLCN-Rag activation downstream of TSC2 loss

Project description:The mechanistic target of rapamycin complex 1 (mTORC1) integrates inputs from growth factors and nutrients, but how mTORC1 autoregulates its activity remains unclear. The MiT/TFE transcription factors are phosphorylated and inactivated by mTORC1 following lysosomal recruitment by RagC/D GTPases in response to amino acid stimulation. We find that starvation-induced lysosomal localization of the RagC/D GAP complex, FLCN:FNIP2, is markedly impaired in a mTORC1-sensitive manner in cells with TSC2 loss, resulting in unexpected TFEB hypophosphorylation and activation upon feeding. TFEB phosphorylation in TSC2-null cells is partially restored by destabilization of the lysosomal folliculin complex (LFC) induced by FLCN mutants and is fully rescued by forced lysosomal localization of the FLCN:FNIP2 dimer. Our data indicate that a negative feedback loop constrains amino acid-induced, FLCN:FNIP2-mediated RagC activity in cells with constitutive mTORC1 signaling, and the resulting MiT/TFE hyperactivation may drive oncogenesis with loss of the TSC2 tumor suppressor.

2022-11-01 | GSE216545 | GEO

A YAP/TAZ-TEAD signaling module links endothelial nutrient acquisition to angiogenic growth

Project description:Angiogenesis, the process by which endothelial cells (ECs) form new blood vessels from existing ones, is intimately linked to the tissue's metabolic milieu and often occurs at nutrient-deficient sites. However, ECs rely on sufficient metabolic resources to support growth and proliferation. How endothelial nutrient acquisition and usage are regulated is unknown. Here we show that these processes are dictated by YAP/TAZ-TEAD – a transcriptional module whose function is highly responsive to changes in the tissue environment. ECs lacking YAP/TAZ or their transcriptional partners, TEAD1, 2, and 4 fail to divide, resulting in stunted vascular growth in mice. Conversely, activation of TAZ, the more abundant paralogue in ECs, boosts proliferation, leading to vascular hyperplasia. We find that YAP/TAZ promote angiogenesis by fueling nutrient mTORC1 signaling. By orchestrating the transcription of a repertoire of cell-surface transporters, YAP/TAZ-TEAD stimulate the import of amino acids and other essential nutrients, thereby enabling mTORC1 pathway activation. Dissociating mTORC1 from these nutrient inputs – elicited by the loss of Rag GTPases – inhibits mTORC1 activity and prevents YAP/TAZ-dependent vascular growth. These findings define a pivotal role for YAP/TAZ-TEAD in steering endothelial mTORC1 and illustrate the essentiality of coordinated nutrient fluxes in the vasculature.

2022-05-08 | PXD026872 | Pride

Proteomic analysis of Raptor-proximal proteins in U2OS cells

Project description:The mammalian target of rapamycin complex 1 (mTORC1) is a key nutrient-sensing hub and a master regulator of cellular growth and metabolism. Activation of mTORC1 by amino acids and growth factors requires its recruitment to the lysosomes. Furthermore, lysosomal distribution has been shown to be intimately involved in the control of mTORC1, where localisation of lysosomes near plasma membrane increases mTORC1 activity. However, the underlying mechanisms by which lysosomal positioning impacts on mTORC1 signalling are not well understood. To understand better the spatial associations of mTORC1, we analysed the proximal ‘interactome’ of the constitutive component of mTORC1, Raptor, using BioID2-based proximity labelling and MS-based proteomics.

2021-09-08 | PXD012795 | Pride

Quantitative Phosphoproteomic Analyses Identify STK11IP as a Lysosome-Specific Substrate of mTORC1 that Regulates Lysosomal Acidification

Project description:The evolutionarily conserved serine/threonine kinase mTORC1 is a central regulator of cell growth and proliferation. mTORC1 is activated on the lysosome surface. However, once mTORC1 is activated, it is unclear whether mTORC1 phosphorylates local lysosomal proteins to regulate specific aspects of lysosomal biology. By integrating analyses of lysosome proteome with mTORC1-regulated phosphoproteome, we identify STK11IP as a lysosome-specific substrate of mTORC1. mTORC1 phosphorylates STK11IP at S404. Knockout of STK11IP leads to a robust increase of autophagy flux. Dephosphorylation of STK11IP at S404 represses the role of STK11IP as an autophagy inhibitor. Mechanistically, STK11IP binds to V-ATPase, and regulates the activity of V-ATPase. Knockout of STK11IP protects mice from fasting or Methionine/Choline-Deficient Diet diet-induced fatty liver. Thus, our study demonstrates that STK11IP phosphorylation represents a novel mechanism for mTORC1 to regulate lysosomal acidification and autophagy, and points to STK11IP as a promising therapeutic target for the amelioration of diseases with aberrant autophagy signaling.

2022-05-20 | PXD031543 | Pride

Functional proteomics identifies acinus L as a direct insulin- and amino acid-dependent mTORC1 substrate

Project description:The serine/threonine kinase mammalian target of rapamycin (mTOR) governs growth, metabolism, and aging in response to insulin and amino acids (aa), and is often activated in metabolic disorders and cancer. Much is known about the regulatory signaling network around mTOR, but surprisingly few direct mTOR substrates have been established to date. To tackle this gap in our knowledge, we took advantage of a combined quantitative phosphoproteomic and interactomic strategy. We analyzed the insulin- and aa-responsive phosphoproteome upon inhibition of the mTOR complex 1 (mTORC1) component raptor, and analyzed in parallel the interactome of endogenous mTOR. By overlaying these two datasets, we identified acinus L as a potential novel mTORC1 target. We confirmed acinus L as a direct mTORC1 substrate by co-immunoprecipitation and MS-enhanced kinase assays. Our study delineates a triple proteomics strategy of combined phosphoproteomics, interactomics, and MS-enhanced kinase assays for the de novo-identification of mTOR network components, and provides a rich source of potential novel mTOR interactors and targets for future investigation. Additional contact details: <a href="mailto:k.thedieck@umcg.nl">Prof. Dr. Kathrin Thedieck</a> Department of Pediatrics, University of Groningen, University Medical Center Groningen (UMCG), 9713 AV Groningen, The Netherlands. Faculty VI - School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, 26111 Oldenburg, Germany. Prof. Dr. Bettina Warscheid Faculty of Biology, Institute of Biology II, University of Freiburg, 79104 Freiburg, Germany. BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.

2015-04-28 | PXD001244 | Pride

mTORC1 feedback to AKT modulates MiT/TFE-driven lysosomal biogenesis and EGFR degradation

Project description:MiT/TFE transcriptional activity controls lysosomal biogenesis and is negatively regulated by the nutrient sensor mTORC1. Some tumors bypass this regulatory circuit via genetic alterations that drive MiT/TFE expression and activity; however, the mechanisms by which cells with intact or constitutive mTORC1 signaling maintain lysosomal catabolism remain to be elucidated. Using the murine epidermis as a model system, we find that epidermal Tsc1 deletion results in a wavy hair phenotype due to increased EGFR degradation. Unexpectedly, constitutive mTORC1 activation increases lysosomal content via up-regulated expression and activity of MiT/TFEs, while genetic or prolonged pharmacologic mTORC1 inactivation has the reverse effect. This paradoxical up-regulation of lysosomal biogenesis by mTORC1 is mediated by feedback inhibition of AKT, and a resulting suppression of AKT-induced MiT/TFE proteasomal degradation. These data suggest that oncogenic feedback loops work to restrain or maintain cellular lysosomal content during chronically inhibited or constitutively active mTORC1 signaling respectively, and reveal a mechanism by which mTORC1 regulates upstream receptor tyrosine kinase signaling.

2020-04-14 | GSE124754 | GEO

Lamtor5 maintains immune homeostasis by regulating lysosomal activity via v-ATPase and mTOR signaling

Project description:Despite accumulating evidences linking defective lysosome function with autoimmune diseases, how the catabolic machinery is regulated for immune homeostasis remains largely unknown. Lamtor5 is a subunit of the Ragulator mediating mTORC1 activation in response to amino acids, but its action mode and physiological role are yet to be addressed. Here we unexpectedly found that myeloid Lamtor5 ablating mice developed spontaneous inflammation and systemic lupus erythematosus (SLE)-like manifestation. Loss of Lamtor5 in macrophages caused impaired vacuolar H⁺-ATPase (v-ATPase) activity, lysosome de-acidification, and aberrant mTORC1 activation, correlating with undesirable inflammatory responses. Mechanistically, we showed that Lamtor5 physically associated with ATP6V1A, an essential subunit of v-ATPase, and promoted the V0/V1 holoenzyme assembly for lysosome acidification. Notably, binding of Lamtor5 to v-ATPase substantially affected lysosomal tethering of Rag GTPase and weakened its interaction with mTORC1 for activation. Importantly, defective Lamtor5 expression, along with impaired lysosomal function and hyperactivation of mTORC1, was corroborated in peripheral blood mononuclear cells (PBMCs) of SLE patients and correlated with disease severity. Overall, our findings establish Lamtor5 as a new lysosome regulator, and elucidate an unappreciated mechanism that coordinates catabolic and anabolic pathways to bolster immune homeostasis preventing autoimmunity.

2024-03-03 | GSE227039 | GEO

Genome wide transcriptional change by GPR155/LYCHOS loss

Project description:Cholesterol, a key building block for cellular membranes and a precursor for steroid hormones, was recently identified as a major nutrient input that activates the master growth regulator, mammalian Target of Rapamycin Complex 1 (mTORC1) kinase. Here we identify a novel lysosomal tranmembrane protein , which we name LYsosomal CHOlesterol Signaling (LYCHOS, previously annotated as GPR155/DEPDC3), as an essential factor that enables cholesterol-dependent activation of mTORC1. RNAseq analysis of LYCHOS-depleted cells showed a pronounced dowregulation of metabolic genes involved in glycolysis, pentose phosphate pathway and lipid biosynthesis.

2022-09-01 | GSE196384 | GEO