GO:1904263 positive regulation of TORC1 signaling: Nutrient-Sensing Pathway, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:1904263 (positive regulation of TORC1 signaling) describes any process that activates or increases the frequency, rate or extent of TORC1 signaling, the central growth-control pathway that couples nutrient availability to cell growth [1,3].
• Amino acid sensors such as Sestrin2 (leucine) and CASTOR proteins (arginine) directly inhibit or activate the GATOR2-GATOR1 axis to control Rag GTPase-dependent TORC1 activation [1,3].
• The GATOR1 complex acts as a GTPase-activating protein (GAP) for RagA/B, and its inhibition by GATOR2 is a key step in positive regulation of TORC1 signaling.
• TORC1 drives anabolic processes including protein synthesis, SAM synthesis and m6A-dependent mRNA translation, linking nutrient sensing to biosynthetic output.
• Dysregulated positive regulation of TORC1 signaling contributes to cancer, aging, metabolic disease and immune dysfunction, making it a major therapeutic target [5,6,8].
• CRISPR knockout, point-mutation, knock-in and overexpression models are essential to dissect causal roles of TORC1 pathway components in health and disease [2,5,6,8].
Description
The mechanistic target of rapamycin complex 1 (TORC1, also known as mTORC1) is a master regulator of cell growth that integrates nutrient, energy and growth-factor signals to control anabolic and catabolic processes [1,3]. The Gene Ontology term GO:1904263, positive regulation of TORC1 signaling, captures any process that activates or increases the frequency, rate or extent of TORC1 signaling. This term is central to understanding how cells sense amino acids, glucose and other cues to decide whether to grow, proliferate or enter quiescence [1,3,7]. Positive regulation of TORC1 signaling is executed by a sophisticated molecular machinery. Cytosolic amino acid sensors such as Sestrin2 for leucine and CASTOR proteins for arginine transmit signals to the GATOR2-GATOR1 complex, which in turn controls the nucleotide-loading state of Rag GTPases [1,3]. When RagA/B are loaded with GTP and RagC/D with GDP, they recruit TORC1 to the lysosomal surface, where the small GTPase Rheb activates its kinase activity. This cascade exemplifies how positive regulation of TORC1 signaling is spatially and temporally organized. For researchers, GO:1904263 provides a precise annotation framework to study genes and pathways that enhance TORC1 activity. Dysregulation of this process is implicated in cancer, aging, metabolic disorders and immune exhaustion, making it a high-priority target for functional genomics and drug discovery [5,6,8]. Understanding the positive regulators of TORC1 signaling is therefore essential for both basic cell biology and translational medicine.
positive regulation of TORC1 signaling At A Glance
| GO ID | GO:1904263 |
|---|---|
| GO term | positive regulation of TORC1 signaling |
| Ontology | biological_process |
| Definition | Any process that activates or increases the frequency, rate or extent of TORC1 signaling. |
| Synonyms | activation of TORC1 signaling; activation of TORC1 signal transduction; positive regulation of TORC1 signal transduction; up regulation of TORC1 signaling; up-regulation of TORC1 signaling; upregulation of TORC1 signaling; up regulation of TORC1 signal transduction; up-regulation of TORC1 signal transduction; upregulation of TORC1 signal transduction |
| Major function | Activation of the TORC1 kinase complex in response to nutrients and growth signals, leading to enhanced protein synthesis, lipid synthesis and cell growth. |
| Parent term | regulation of TORC1 signaling (GO:1904261) |
| Opposite term | negative regulation of TORC1 signaling (GO:1904262) |
| Related cellular component | TORC1 complex; lysosomal membrane; GATOR1 complex; GATOR2 complex |
| Related molecular function | Rag GTPase activity; GTPase-activating protein activity; amino acid sensor activity |
What Is GO:1904263?
GO:1904263 (positive regulation of TORC1 signaling) is a biological process term defined as any process that activates or increases the frequency, rate or extent of TORC1 signaling. In practical terms, it encompasses the molecular events that turn on or amplify the TORC1 kinase cascade, including amino acid sensing, Rag GTPase activation, lysosomal recruitment of TORC1, and Rheb-mediated activation. It is the opposite of negative regulation of TORC1 signaling (GO:1904262) and is a child of regulation of TORC1 signaling (GO:1904261).
Why Is positive regulation of TORC1 signaling Important in Cell Biology?
Positive regulation of TORC1 signaling is fundamental to cell growth, proliferation and survival. It ensures that cells only engage in energy-expensive anabolic processes when nutrients are abundant. Defects in this regulation lead to a wide range of pathologies, including cancer, where hyperactive TORC1 signaling drives uncontrolled growth, and metabolic disorders such as diabetes and obesity [5,6,8]. Moreover, TORC1 signaling is a key determinant of immune cell function, with recent studies showing that its modulation affects T cell quiescence and exhaustion [6,8]. Understanding the positive regulators of TORC1 signaling therefore has broad implications for aging, immunity and cancer therapy.
• Controls cell growth and proliferation by integrating amino acid, glucose and growth factor signals [1,3].
• Dysregulation is a hallmark of many cancers, where hyperactive TORC1 signaling promotes tumorigenesis.
• Plays a critical role in aging and longevity, with TORC1 inhibition extending lifespan in model organisms.
• Regulates immune cell quiescence and exhaustion, impacting immunotherapy and vaccine responses [6,8].
• Coordinates protein synthesis through SAM synthesis and m6A-dependent mRNA translation.
• Involved in placental development and trophoblast syncytialization, affecting pregnancy outcomes.
• Serves as a target for drugs like rapamycin and rapalogs in transplantation and oncology [1,3].
• Modulates autophagy, a process critical for cellular quality control and neurodegeneration.
• Affects lipid and nucleotide synthesis, linking nutrient status to membrane biogenesis.
• Provides a rich source of therapeutic targets for metabolic diseases and aging-related disorders [5,8].
What Happens During positive regulation of TORC1 signaling?
Amino acid sensing and signal initiation
In simple terms: Cells first check whether amino acids are available before turning on growth.
Positive regulation of TORC1 signaling begins with the sensing of intracellular amino acids. Sestrin2 acts as a leucine sensor; in the absence of leucine, Sestrin2 binds and inhibits GATOR2, a positive regulator of TORC1 signaling. Similarly, CASTOR proteins sense arginine and transmit signals to the GATOR2 complex. When amino acids are abundant, Sestrin2 and CASTOR proteins release GATOR2, allowing it to inhibit GATOR1 and thereby promote TORC1 activation [1,3].
GATOR1-GATOR2 regulation of Rag GTPases
In simple terms: A molecular switch called GATOR1 turns off the Rag proteins, and GATOR2 turns off GATOR1 to keep TORC1 active.
The GATOR1 complex functions as a GTPase-activating protein (GAP) for RagA/B, converting them to the inactive GDP-bound state and thereby inhibiting TORC1 signaling. GATOR2, a positive regulator, binds and inhibits GATOR1, relieving this inhibition and allowing RagA/B to remain GTP-loaded. This dynamic interplay between GATOR1 and GATOR2 is a central node in the positive regulation of TORC1 signaling.
Lysosomal recruitment and Rheb-mediated activation
In simple terms: Once the Rag switch is on, TORC1 moves to the lysosome where it meets its activator Rheb.
When RagA/B are GTP-loaded and RagC/D are GDP-loaded, they recruit TORC1 to the lysosomal surface through interactions with the Ragulator complex. At the lysosome, the small GTPase Rheb directly binds and activates the TORC1 kinase domain [1,3]. This spatial organization ensures that TORC1 is activated only when nutrients are present and the lysosomal surface is permissive.
Downstream anabolic outputs
In simple terms: Active TORC1 then flips on many growth programs, including protein and lipid synthesis.
Activated TORC1 phosphorylates downstream effectors such as S6K1 and 4E-BP1 to promote protein synthesis. It also stimulates SAM synthesis and m6A-dependent mRNA translation, linking nutrient sensing to biosynthetic capacity. Additionally, TORC1 promotes lipid synthesis and inhibits autophagy, collectively driving cell growth and proliferation [1,3].
Feedback and crosstalk with other pathways
In simple terms: The pathway has built-in brakes and connections to other signals to avoid runaway growth.
Positive regulation of TORC1 signaling is balanced by negative feedback loops, such as S6K1-mediated phosphorylation of IRS-1, which dampens insulin signaling. Crosstalk with AMPK, which inhibits TORC1 under low energy conditions, further integrates energy status. Recent studies have also revealed that ARMH4 maintains a positive-feedback growth signaling circuit, accelerating aging when dysregulated.
Key Genes Involved in GO:1904263 positive regulation of TORC1 signaling
The following genes and proteins are core components and regulators of positive regulation of TORC1 signaling, as supported by the cited literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| Sestrin2 (SESN2) | Leucine sensor that inhibits GATOR2 in the absence of leucine | Knockout models reveal amino acid-dependent TORC1 activation |
| CASTOR1 | Arginine sensor that binds GATOR2 and regulates TORC1 | Point mutations in arginine-binding pocket affect TORC1 signaling |
| GATOR1 (DEPDC5, NPRL2, NPRL3) | GTPase-activating protein for RagA/B, inhibits TORC1 | Knockout causes hyperactive TORC1 and is linked to cancer |
| GATOR2 (WDR24, WDR59, MIOS, SEC13, SEH1L) | Inhibits GATOR1, positive regulator of TORC1 | Overexpression enhances TORC1 signaling |
| RagA/B (RRAGA, RRAGB) | GTPases that recruit TORC1 to lysosome when GTP-loaded | Point mutations locking GTP-bound state activate TORC1 |
| RagC/D (RRAGC, RRAGD) | GTPases that partner with RagA/B; GDP-bound state is active | Knock-in of GDP-locked mutants affects TORC1 recruitment |
| Rheb (RHEB) | Direct activator of TORC1 kinase at lysosome | Overexpression drives constitutive TORC1 activity |
| mTOR (MTOR) | Catalytic subunit of TORC1 | Knockout is lethal; conditional models used to study tissue-specific roles |
| Raptor (RPTOR) | Scaffold protein of TORC1 | Knockdown disrupts TORC1 assembly and signaling |
| S6K1 (RPS6KB1) | Downstream effector promoting protein synthesis | Phosphorylation readout for TORC1 activity |
| 4E-BP1 (EIF4EBP1) | Downstream effector inhibiting translation initiation | Phosphorylation relieves inhibition of cap-dependent translation |
| TFEB | Transcription factor regulated by TORC1; controls lysosomal biogenesis | Knockout affects trophoblast syncytialization |
| LINE1 | Retrotransposon whose splicing regulates T cell quiescence via TORC1 | Knockdown alters protein synthesis and exhaustion [6,8] |
| ARMH4 | Maintains positive-feedback growth signaling circuit | Knockout accelerates aging in mouse models |
| DEPDC5 | Subunit of GATOR1 | Mutations linked to focal epilepsy and cancer |
| NPRL2 | Subunit of GATOR1 | Tumor suppressor, loss activates TORC1 |
| LAMTOR1 | Component of Ragulator complex | Required for lysosomal recruitment of TORC1 |
| AMPK (PRKAA1/2) | Energy sensor that inhibits TORC1 | Activators reduce TORC1 signaling |
How Is positive regulation of TORC1 signaling Regulated?
Positive regulation of TORC1 signaling is tightly controlled by multiple inputs. Amino acids such as leucine and arginine are sensed by Sestrin2 and CASTOR proteins, respectively, which modulate GATOR2 activity [1,3]. Growth factors activate TORC1 through the PI3K-AKT pathway, which inhibits TSC1/2 and thereby activates Rheb. Energy stress activates AMPK, which inhibits TORC1 both directly and through TSC2. Additionally, recent work has identified ARMH4 as a factor that maintains a positive-feedback growth signaling circuit, highlighting additional layers of regulation. These regulatory mechanisms ensure that TORC1 is active only under favorable conditions.
positive regulation of TORC1 signaling and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| DEPDC5 | Focal epilepsy, cancer | Knockout in HEK293T cells to assess TORC1 activity |
| NPRL2 | Tumor suppressor loss in cancer | Knockout in cancer cell lines followed by proliferation assays |
| ARMH4 | Aging and age-related decline | Knockout mouse model to measure lifespan and TORC1 signaling |
| LINE1 | T cell exhaustion and autoimmunity | Knockdown in primary human T cells to assess quiescence [6,8] |
| TFEB | Placental insufficiency | Knockout in trophoblast stem cells and mouse models |
Cancer
Hyperactive positive regulation of TORC1 signaling is a common feature of many cancers. Mutations in GATOR1 subunits such as DEPDC5 and NPRL2 lead to constitutive TORC1 activation and are associated with tumorigenesis. Overexpression of Rheb or Rag GTPases can also drive oncogenic growth [1,3]. Targeting positive regulators of TORC1 signaling is therefore a promising therapeutic strategy.
Aging and metabolic disorders
Dysregulated TORC1 signaling contributes to aging and metabolic diseases. ARMH4 maintains a positive-feedback growth signaling circuit that accelerates aging when overactive, and its knockout extends lifespan in mice. Conversely, excessive TORC1 activity is linked to insulin resistance and obesity, making positive regulators attractive targets for metabolic intervention [1,3].
Immune dysfunction and exhaustion
TORC1 signaling is critical for T cell quiescence and activation. LINE1 elements are spliced in non-canonical transcript variants to regulate T cell quiescence and exhaustion, in part through TORC1-dependent protein synthesis [6,8]. Modulating positive regulation of TORC1 signaling may enhance CAR-T cell persistence and function.
Placental development
TFEB, a downstream target of TORC1, safeguards trophoblast syncytialization in humans and mice. Disruption of TORC1 signaling in trophoblasts can lead to placental insufficiency and pregnancy complications. This highlights the importance of positive regulation of TORC1 signaling in developmental biology.
From positive regulation of TORC1 signaling-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of GATOR1 activate TORC1? | CRISPR knockout of DEPDC5 in HEK293T cells |
| Does a point mutation in Sestrin2 affect leucine sensing? | CRISPR point mutation (e.g., Sestrin2 W444A) in cell lines |
| Does Rheb overexpression drive TORC1 signaling? | CRISPR knock-in of constitutive active Rheb or overexpression |
| How does ARMH4 regulate aging? | ARMH4 knockout mouse model |
| What is the role of LINE1 in T cell quiescence? | CRISPR interference or knockout in primary T cells [6,8] |
| How does TFEB affect syncytialization? | TFEB knockout in human trophoblast stem cells |
How to Study the positive regulation of TORC1 signaling Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Western blot for p-S6K1 (T389) | TORC1 kinase activity | Assessing activation state after amino acid stimulation |
| Ribo-seq | Global translation efficiency | Identifying mRNAs whose translation is TORC1-dependent |
| Immunofluorescence | Lysosomal localization of TORC1 | Visualizing Rag-dependent recruitment |
| CRISPR knockout screen | Genes required for TORC1 activation | Discovering novel positive regulators |
| Co-immunoprecipitation | Protein-protein interactions (e.g., Sestrin2-GATOR2) | Mapping sensor complexes [1,3] |
| GTPase activity assay | Rag GTPase nucleotide loading | Measuring GATOR1 GAP activity |
| Polysome profiling | mRNA translation status | Confirming m6A-dependent translation |
| Flow cytometry | T cell quiescence and exhaustion markers | Studying LINE1 effects on T cells [6,8] |
Phospho-proteomics and immunoblotting
Measuring phosphorylation of TORC1 substrates such as S6K1 (T389) and 4E-BP1 (S65) is a standard method to assess positive regulation of TORC1 signaling. Phospho-specific antibodies enable quantitative readouts in knockout or mutant cell lines.
Ribo-seq and polysome profiling
Ribosome profiling (Ribo-seq) captures global translation changes downstream of TORC1 activation. This method has been used to show that TORC1 stimulates SAM synthesis and m6A-dependent mRNA translation.
Live-cell imaging of lysosomal recruitment
Fluorescently tagged TORC1 components (e.g., mTOR-GFP) and lysosomal markers allow real-time visualization of TORC1 recruitment to the lysosome upon amino acid stimulation. This is critical for understanding spatial regulation.
CRISPR screens and functional genomics
Genome-wide CRISPR knockout screens can identify positive regulators of TORC1 signaling. For example, screens for resistance to TORC1 inhibitors have revealed components of the GATOR1 complex.
How CRISPR Can Be Used to Study GO:1904263 positive regulation of TORC1 signaling
Knockout
CRISPR knockout of positive regulators such as DEPDC5 or NPRL2 leads to constitutive TORC1 activation, providing a powerful model to study downstream effects. Knockout of Sestrin2 or CASTOR1 abolishes amino acid sensing and alters TORC1 responsiveness [1,3].
Point Mutation
Point mutations can dissect specific domains. For example, mutation of the leucine-binding pocket of Sestrin2 (W444A) prevents leucine sensing and keeps TORC1 off. Similarly, point mutations in CASTOR1 that disrupt arginine binding affect TORC1 signaling.
Knock-in
Knock-in of tagged or mutant alleles allows precise tracking and functional analysis. Knock-in of GFP-tagged mTOR or Rag GTPases enables live-cell imaging of lysosomal recruitment. Knock-in of constitutively active Rheb can drive TORC1 signaling in specific tissues.
Overexpression
Overexpression of positive regulators such as Rheb or GATOR2 components enhances TORC1 signaling and can transform cells [1,7]. Conversely, overexpression of dominant-negative mutants can inhibit the pathway. These models are useful for gain-of-function studies.
How EDITGENE Supports positive regulation of TORC1 signaling Research
Researchers studying positive regulation of TORC1 signaling-related genes often need to determine whether a candidate gene is causally involved in pathway activation, and to dissect the precise molecular mechanism. EDITGENE provides end-to-end CRISPR services to generate knockout, point-mutation, knock-in and overexpression cell models, as well as library screening and bioinformatics support, enabling rigorous functional validation of TORC1 regulators.
Contact EDITGENE today to design your custom CRISPR model for positive regulation of TORC1 signaling research.
Frequently Asked Questions About positive regulation of TORC1 signaling
What is GO:1904263?
GO:1904263 is the Gene Ontology term for positive regulation of TORC1 signaling, defined as any process that activates or increases the frequency, rate or extent of TORC1 signaling.
What genes are involved in positive regulation of TORC1 signaling?
Key genes include Sestrin2 (leucine sensor), CASTOR1 (arginine sensor), GATOR1 (DEPDC5, NPRL2, NPRL3), GATOR2 (WDR24, WDR59, MIOS), Rag GTPases (RRAGA/B/C/D), Rheb, and mTOR itself [1,3,7].
How is TORC1 signaling activated by amino acids?
Amino acids such as leucine and arginine are sensed by Sestrin2 and CASTOR proteins, which regulate GATOR2-GATOR1 to control Rag GTPase loading and lysosomal recruitment of TORC1 [1,3].
What is the role of GATOR1 in TORC1 signaling?
GATOR1 is a GTPase-activating protein for RagA/B that inhibits TORC1 signaling; its loss leads to constitutive TORC1 activation.
What diseases are associated with dysregulated TORC1 signaling?
Dysregulated TORC1 signaling is linked to cancer, aging, metabolic disorders, immune exhaustion, and placental insufficiency [2,5,6,7,8].
How can I study positive regulation of TORC1 signaling in the lab?
Common methods include phospho-immunoblotting for p-S6K1, Ribo-seq, live-cell imaging of lysosomal recruitment, and CRISPR screens [4,7].
What CRISPR models are available for TORC1 research?
EDITGENE offers knockout, point-mutation, knock-in, and overexpression cell models for genes in the TORC1 pathway, as well as library screening and bioinformatics services.
What is the difference between TORC1 and mTORC1?
TORC1 (target of rapamycin complex 1) and mTORC1 (mechanistic target of rapamycin complex 1) refer to the same complex; TORC1 is the standard Gene Ontology nomenclature.
How does ARMH4 regulate TORC1 signaling?
ARMH4 maintains a positive-feedback growth signaling circuit that sustains TORC1 activity; its knockout accelerates aging in mice.
Can TORC1 signaling be targeted therapeutically?
Yes, rapamycin and its analogs inhibit TORC1 and are used in transplantation and cancer; however, targeting positive regulators specifically may offer new opportunities [1,3].
Conclusion
Positive regulation of TORC1 signaling (GO:1904263) is a fundamental biological process that integrates nutrient and growth signals to control cell growth. The pathway involves a sophisticated network of amino acid sensors, GATOR complexes, Rag GTPases and Rheb, all of which converge on TORC1 activation [1,3,7]. Dysregulation of this process underlies cancer, aging, metabolic and immune disorders, making it a prime target for therapeutic intervention [5,6,8]. CRISPR-based models are indispensable for dissecting the causal roles of individual components in this pathway. EDITGENE provides comprehensive services to generate knockout, point-mutation, knock-in and overexpression cell models, enabling researchers to uncover new mechanisms and identify drug targets in TORC1 signaling.
References
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- 2. Zheng W et al.. 2024. TFEB safeguards trophoblast syncytialization in humans and mice.. Proc Natl Acad Sci U S A 121(28):e2404062121 PMID: 38968109
- 3. Chantranupong L et al.. 2016. The CASTOR Proteins Are Arginine Sensors for the mTORC1 Pathway.. Cell 165(1):153-164 PMID: 26972053
- 4. Villa E et al.. 2021. mTORC1 stimulates cell growth through SAM synthesis and m(6)A mRNA-dependent control of protein synthesis.. Mol Cell 81(10):2076-2093.e9 PMID: 33756106
- 5. Fang Y et al.. 2025. ARMH4 accelerates aging by maintaining a positive-feedback growth signaling circuit.. Nat Commun 17(1):812 PMID: 41390521
- 6. Marasca F et al.. 2022. LINE1 are spliced in non-canonical transcript variants to regulate T cell quiescence and exhaustion.. Nat Genet 54(2):180-193 PMID: 35039641
- 7. Bar-Peled L et al.. 2013. A Tumor suppressor complex with GAP activity for the Rag GTPases that signal amino acid sufficiency to mTORC1.. Science 340(6136):1100-6 PMID: 23723238
- 8. Burattin FV et al.. 2024. LINE1 modulate human T cell function by regulating protein synthesis during the life span.. Sci Adv 10(41):eado2134 PMID: 39383231
