GO:0140785 amino acid sensor activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0140785 amino acid sensor activity is a molecular function defined as binding to and responding, e.g. by conformational change, to changes in the cellular level of an amino acid.
• The best-characterized amino acid sensors include Sestrin2 (leucine sensor for mTORC1) and GCN2/GCN1 (amino acid response pathway), which detect amino acid availability and trigger downstream signaling [2,3].
• Amino acid sensing is central to mTORC1 signaling, integrated stress response, autophagy, and metabolic reprogramming in cancer and immune cells [1,5,6].
• Dysregulated amino acid sensing contributes to cancer, metabolic disorders, and immune dysfunction, making it a therapeutic target [1,6].
• CRISPR knockout, point mutation, knock-in, and overexpression models enable causal dissection of amino acid sensor genes in disease and metabolism [2,3,5].
• EDITGENE provides end-to-end CRISPR services, including cell model generation and library screening, to study amino acid sensor activity.
Description
Amino acid sensor activity (GO:0140785) is a molecular function that enables a protein to bind an amino acid and respond to changes in its cellular concentration, often through a conformational change [2,3]. This activity is fundamental to how cells monitor nutrient status and coordinate growth, metabolism, and stress responses. The QuickGO definition captures this as binding to and responding, e.g. by conformational change, to changes in the cellular level of an amino acid. Researchers study this term because amino acid sensors are gatekeepers of major signaling pathways, including mTORC1 and the integrated stress response, and their dysfunction is linked to cancer, metabolic disease, and immune regulation [1,5,6]. Understanding amino acid sensor activity at the molecular level provides a foundation for targeting these pathways in disease.
amino acid sensor activity At A Glance
| GO ID | GO:0140785 |
|---|---|
| GO term | amino acid sensor activity |
| Ontology | molecular_function |
| Synonym | amino acid sensing activity |
| Major function | Binding to and responding to changes in cellular amino acid levels |
| Definition source | QuickGO |
| Example sensors | Sestrin2 (leucine), GCN2 (amino acid deficiency) |
| Related pathways | mTORC1 signaling, integrated stress response, autophagy |
What Is GO:0140785?
Amino acid sensor activity (GO:0140785) is the molecular function of binding to an amino acid and responding to fluctuations in its intracellular levels, typically via a conformational change that alters the sensor's interactions or activity. This function allows cells to detect amino acid availability and initiate appropriate signaling or metabolic responses.
Why Is amino acid sensor activity Important in Cell Biology?
Amino acid sensor activity is essential for cellular adaptation to nutrient availability. It controls protein synthesis, autophagy, and metabolic homeostasis through pathways such as mTORC1 and GCN2 [2,3,5]. Dysregulation of amino acid sensing is implicated in cancer, where it supports tumor growth and survival, and in immune cell function, affecting responses to infection and inflammation [1,6]. Thus, understanding this activity offers insights into basic cell biology and potential therapeutic targets.
• Regulates mTORC1 signaling in response to leucine and other amino acids.
• Initiates the integrated stress response via GCN2 during amino acid deficiency.
• Controls autophagy and lysosomal catabolic activity through mTORC1.
• Modulates red blood cell clearance and iron metabolism via GCN2 in liver macrophages.
• Plays a role in cancer metabolism and tumor growth.
• Influences immune responses and inflammation.
• Impacts gut-brain circuits for fat preference.
• Is targeted by viral proteins to modulate ER stress and autophagy.
• Provides targets for therapeutic intervention in metabolic diseases.
• Enables mechanistic studies using CRISPR models [2,3,5].
Core Biology of amino acid sensor activity
Amino acid binding and conformational change
In simple terms: The sensor protein physically binds an amino acid, which changes its shape.
Amino acid sensors such as Sestrin2 bind leucine directly, causing a conformational change that disrupts its interaction with GATOR2 and thereby activates mTORC1. Similarly, GCN2 responds to uncharged tRNA during amino acid deficiency, but the sensor activity involves detection of amino acid levels through GCN1 and ribosomal state.
Signal transduction to downstream effectors
In simple terms: After sensing, the protein sends a signal to other molecules.
Upon leucine binding, Sestrin2 releases GATOR2, leading to mTORC1 activation and promotion of protein synthesis. In the amino acid response pathway, GCN1 couples GCN2 to the ribosome to initiate signaling when amino acids are limiting.
Integration with cellular metabolism
In simple terms: The sensing activity is connected to how cells use energy and nutrients.
Amino acid sensing is integrated with lysosomal catabolic activity; mTORC1 regulates V-ATPase assembly to control lysosomal function. This coordination ensures that cells adapt metabolism to nutrient availability.
Physiological roles in immunity and beyond
In simple terms: Amino acid sensing affects whole-body processes like immunity and iron handling.
GCN2 controls red blood cell clearance and iron metabolism through regulation of liver macrophages, demonstrating a role for amino acid sensing in immune and metabolic homeostasis. Additionally, amino acid sensing is involved in gut-brain circuits for fat preference.
Key Genes Involved in GO:0140785 amino acid sensor activity
The following genes and proteins are central to amino acid sensor activity and its downstream signaling.
| Gene | Major Role | Research Relevance |
|---|---|---|
| SESN2 | Leucine sensor for mTORC1 | Direct binding of leucine; regulates mTORC1 |
| GCN2 (EIF2AK4) | Amino acid deficiency sensor | Initiates integrated stress response |
| GCN1 | Couples GCN2 to ribosome | Required for GCN2 activation |
| mTOR | Downstream kinase | Central to nutrient signaling [2,5] |
| GATOR2 | mTORC1 regulator | Target of Sestrin2 [2,7] |
| V-ATPase | Lysosomal proton pump | Regulated by mTORC1 |
| STING1 | Immune signaling adaptor | Degraded via autophagy triggered by ER stress |
| SARS-CoV-2 NSP6 | Viral protein | Triggers ER stress and autophagy |
| Rag GTPases | mTORC1 activators | Mediate amino acid signaling |
| LARS1 | Leucyl-tRNA synthetase | Potential leucine sensor |
| SLC38A9 | Lysosomal arginine sensor | Activates mTORC1 |
| CASTOR1 | Cytosolic arginine sensor | Regulates mTORC1 |
| SAMTOR | S-adenosylmethionine sensor | Links methionine to mTORC1 |
| GCN1L1 | GCN1-like protein | Ribosome quality control |
| ATF4 | Transcription factor | Downstream of GCN2 |
| CHOP (DDIT3) | Stress-induced transcription factor | ER stress and autophagy |
| mTORC1 | Nutrient-sensing complex | Integrates amino acid signals [2,5] |
How Is amino acid sensor activity Regulated?
Amino acid sensor activity is regulated by the availability of specific amino acids. For example, Sestrin2 binds leucine directly, and this binding is required for mTORC1 activation. GCN2 is activated by uncharged tRNA during amino acid limitation, a process that requires GCN1 and ribosomal stalling. Additionally, mTORC1 regulates lysosomal catabolic activity by controlling V-ATPase assembly, providing feedback regulation. These mechanisms ensure that cells respond appropriately to fluctuating nutrient levels.
amino acid sensor activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| SESN2 | Cancer metabolism | Knockout and point mutation in cancer cell lines [2,6] |
| GCN2 (EIF2AK4) | Anemia, immune regulation | Knockout mouse models [1,3] |
| STING1 | Viral infection, autoimmunity | Overexpression and knockout in macrophages |
| mTOR | Cancer, metabolic disorders | Knock-in of activating mutations [5,6] |
| V-ATPase | Lysosomal storage diseases | Knockout of subunits |
Cancer
Amino acid sensing is frequently dysregulated in cancer, where it supports anabolic growth and survival. Sestrin2 and mTORC1 signaling are often altered to promote tumorigenesis. Targeting amino acid sensors may offer therapeutic strategies.
Metabolic and immune disorders
GCN2-mediated amino acid sensing controls red blood cell clearance and iron metabolism in liver macrophages, linking it to immune and metabolic homeostasis. Dysregulation can contribute to anemia and inflammation.
Viral infection and ER stress
SARS-CoV-2 NSP6 triggers ER stress-induced autophagy to degrade STING1, a process that intersects with amino acid sensing pathways. This highlights how pathogens manipulate nutrient sensing to evade immunity.
From amino acid sensor activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does Sestrin2 directly sense leucine? | Point mutation of leucine-binding residues |
| What is the role of GCN2 in iron metabolism? | Knockout mouse |
| How does GCN1 couple GCN2 to ribosomes? | Knock-in of tagged GCN1 |
| Does mTORC1 regulate V-ATPase assembly? | Knockout of mTORC1 components |
| Can amino acid sensing be targeted in cancer? | Overexpression of sensors in cancer cells |
| How does NSP6 trigger autophagy? | Overexpression of NSP6 |
How to Study the amino acid sensor activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Isothermal titration calorimetry | Binding affinity | Amino acid-sensor interaction |
| CRISPR knockout screening | Gene essentiality | Identify sensing pathway components |
| Phosphoproteomics | Signaling changes | mTORC1 or GCN2 activity [3,5] |
| Live-cell imaging | Sensor conformational change | Real-time sensing |
| Ribo-seq | Translation efficiency | Downstream of GCN2 |
| RNA-seq | Transcriptional changes | ATF4 target genes |
| Immunoblotting | Protein levels and modifications | Validate sensor expression [1,8] |
Biochemical binding assays
Direct binding of amino acids to sensors like Sestrin2 can be measured using isothermal titration calorimetry or surface plasmon resonance.
Genetic screens and CRISPR libraries
CRISPR knockout libraries can identify genes required for amino acid sensing and downstream signaling.
Phosphoproteomics
Changes in phosphorylation of downstream effectors such as mTORC1 substrates or eIF2α can be monitored by mass spectrometry [3,5].
Live-cell imaging
Fluorescent reporters can track conformational changes or localization of sensors in response to amino acid levels [2,5].
How CRISPR Can Be Used to Study GO:0140785 amino acid sensor activity
Knockout
CRISPR knockout of amino acid sensor genes such as SESN2 or GCN2 can reveal their requirement for mTORC1 signaling or stress responses [2,3].
Point Mutation
Introducing point mutations in the amino acid-binding pocket of Sestrin2 can abolish leucine sensing and validate the sensor mechanism.
Knock-in
Knock-in of tagged versions of GCN1 or mTOR allows tracking of their localization and interactions in live cells [3,5].
Overexpression
Overexpression of amino acid sensors or viral proteins like NSP6 can amplify signaling and reveal downstream effects such as autophagy.
How EDITGENE Supports amino acid sensor activity Research
Researchers studying amino acid sensor activity-related genes often need to determine whether a candidate gene is causally involved in sensing and downstream signaling. EDITGENE provides CRISPR-based cell models to dissect these mechanisms with precision.
Contact EDITGENE today to design your custom CRISPR model for amino acid sensor activity research.
Frequently Asked Questions About amino acid sensor activity
What is amino acid sensor activity?
It is a molecular function (GO:0140785) where a protein binds an amino acid and responds to changes in its cellular level, often by conformational change [2,3].
What genes are involved in amino acid sensing?
Key genes include SESN2, GCN2 (EIF2AK4), GCN1, mTOR, and GATOR2 [2,3,7].
How does Sestrin2 sense leucine?
Sestrin2 directly binds leucine, causing a conformational change that releases GATOR2 and activates mTORC1.
What is the role of GCN2 in amino acid sensing?
GCN2 is activated by uncharged tRNA during amino acid deficiency and initiates the integrated stress response.
How is amino acid sensing linked to cancer?
Dysregulated amino acid sensing supports cancer cell growth and survival, making it a therapeutic target.
Can CRISPR be used to study amino acid sensors?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are widely used [2,3,5].
What diseases are associated with amino acid sensor dysfunction?
Cancer, metabolic disorders, anemia, and immune dysfunction [1,6].
How does mTORC1 regulate lysosomal activity?
mTORC1 controls V-ATPase assembly to modulate lysosomal catabolic activity.
What methods are used to measure amino acid sensor activity?
Biochemical binding assays, phosphoproteomics, live-cell imaging, and CRISPR screens [2,3,5].
What services does EDITGENE offer for amino acid sensor research?
Knockout, point mutation, knock-in, overexpression cell models, CRISPR library screening, and bioinformatics [2,3,5].
Conclusion
Amino acid sensor activity (GO:0140785) is a critical molecular function that enables cells to detect and respond to amino acid availability. Its dysregulation is implicated in cancer, metabolic, and immune disorders. CRISPR-based models and EDITGENE services provide powerful tools to dissect these mechanisms and identify therapeutic targets.
References
- 1. Toboz P et al.. 2022. The amino acid sensor GCN2 controls red blood cell clearance and iron metabolism through regulation of liver macrophages.. Proc Natl Acad Sci U S A 119(35):e2121251119 PMID: 35994670
- 2. Wolfson RL et al.. 2016. Sestrin2 is a leucine sensor for the mTORC1 pathway.. Science 351(6268):43-8 PMID: 26449471
- 3. Zhou C et al.. 2025. GCN1 couples GCN2 to ribosomal state to initiate amino acid response pathway signaling.. Science 390(6768):eads8728 PMID: 41037622
- 4. Li M et al.. 2022. Gut-brain circuits for fat preference.. Nature 610(7933):722-730 PMID: 36070796
- 5. Ratto E et al.. 2022. Direct control of lysosomal catabolic activity by mTORC1 through regulation of V-ATPase assembly.. Nat Commun 13(1):4848 PMID: 35977928
- 6. Lin Z et al.. 2025. Amino acid sensing in cancer.. Pharmacol Res 221:108003 PMID: 41120020
- 7. Valenstein ML et al.. 2022. Structure of the nutrient-sensing hub GATOR2.. Nature 607(7919):610-616 PMID: 35831510
- 8. Jiao P et al.. 2023. SARS-CoV-2 nonstructural protein 6 triggers endoplasmic reticulum stress-induced autophagy to degrade STING1.. Autophagy 19(12):3113-3131 PMID: 37482689
