GO:0006563 L-serine metabolic process: Biosynthesis Pathway, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0006563 (L-serine metabolic process) describes all chemical reactions and pathways involving L-serine, the (2S)-amino acid central to protein synthesis, one-carbon metabolism, and neurotransmission.
• The phosphorylated pathway (PHGDH, PSAT1, PSPH) is the main de novo route for L-serine biosynthesis in humans, and its enzymes form a multienzyme metabolic assembly.
• L-serine is a precursor for glycine, cysteine, sphingolipids, nucleotides, and glutathione, linking it to redox balance and biosynthetic capacity.
• Impaired glycolysis-derived L-serine production in astrocytes is associated with cognitive deficits in Alzheimer's disease models.
• Serine metabolic reprogramming supports tumor growth and therapy resistance, including lenvatinib resistance in hepatocellular carcinoma and gastric cancer cell survival through SLC1A4-mediated uptake.
• Dysregulated serine metabolism participates in neuroinflammation and epilepsy through neuron-glia crosstalk and mtDNA leakage.
Description
L-serine is a non-essential amino acid that nevertheless plays essential roles in cell physiology. GO:0006563, L-serine metabolic process, is the biological process ontology term that encompasses the chemical reactions and pathways involving L-serine, the L-enantiomer of serine, i.e. (2S)-2-amino-3-hydroxypropanoic acid. This process includes de novo biosynthesis, interconversion with glycine, and utilization of L-serine as a precursor for macromolecules and signaling molecules. Because L-serine sits at the intersection of amino acid metabolism, one-carbon metabolism, and neurotransmission, its regulation is relevant to cancer, neurodegeneration, and metabolic disease. In mammalian cells, L-serine can be synthesized de novo from the glycolytic intermediate 3-phosphoglycerate through the phosphorylated pathway, or taken up from the extracellular environment. The phosphorylated pathway is catalyzed by PHGDH, PSAT1, and PSPH, and evidence indicates that these enzymes can assemble into a multienzyme metabolic assembly that channels intermediates efficiently. In the brain, L-serine is produced by astrocytes and supports neuronal function, linking metabolism with neurotransmission. In cancer, serine metabolism is frequently reprogrammed to support proliferation and resistance to therapy. For researchers, GO:0006563 provides a structured framework to interpret gene expression, metabolomic, and functional genomics data. It helps connect individual enzymes and transporters to pathway-level phenotypes such as proliferation, redox homeostasis, and neuroinflammation. Understanding this process at the molecular level is therefore central to both basic cell biology and translational research.
L-serine metabolic process At A Glance
| GO ID | GO:0006563 |
|---|---|
| GO term | L-serine metabolic process |
| Ontology | biological_process |
| Synonym | L-serine metabolism |
| Definition | The chemical reactions and pathways involving L-serine, the L-enantiomer of serine, i.e. (2S)-2-amino-3-hydroxypropanoic acid. |
| Major function | Biosynthesis, interconversion, transport, and utilization of L-serine for protein synthesis, one-carbon metabolism, and neurotransmission. |
| Key enzymes | PHGDH, PSAT1, PSPH (phosphorylated pathway); SHMT1/2 (serine-glycine interconversion). |
| Key transporters | SLC1A4 and related amino acid transporters mediate L-serine uptake. |
| Related pathways | Glycolysis, one-carbon metabolism, glutathione synthesis, sphingolipid metabolism. |
What Is GO:0006563?
GO:0006563 (L-serine metabolic process) is defined by QuickGO as the chemical reactions and pathways involving L-serine, the L-enantiomer of serine, i.e. (2S)-2-amino-3-hydroxypropanoic acid. In practice, this term covers the biosynthesis of L-serine from glycolytic precursors, its interconversion with other amino acids such as glycine, its uptake and transport, and its use as a substrate for downstream biosynthetic and signaling pathways.
Why Is L-serine metabolic process Important in Cell Biology?
L-serine metabolic process is important because it supplies a hub metabolite that feeds protein synthesis, one-carbon metabolism, antioxidant defense, and neurotransmitter production. Disruption of this process has been linked to cognitive deficits in Alzheimer's disease models, tumor growth and therapy resistance, and neuroinflammatory conditions such as epilepsy. Because multiple enzymes and transporters contribute to L-serine homeostasis, the pathway is a rich source of candidate targets for metabolic and neurological disease research.
• Provides L-serine for protein synthesis and as a precursor for glycine, cysteine, and nucleotides.
• Supports one-carbon metabolism and methylation reactions through serine-glycine interconversion.
• Contributes to glutathione production and redox balance, as shown in metabolic engineering studies.
• Is essential for brain function; astrocytic L-serine production supports neurotransmission.
• Is reprogrammed in cancers such as hepatocellular carcinoma and gastric cancer to support growth and drug resistance.
• Participates in neuroinflammation and epilepsy through neuron-glia crosstalk and serine metabolic reprogramming.
• Is a target for metabolic engineering to improve production of value-added compounds like glutathione.
• Its multienzyme organization offers a model for studying metabolic channeling and enzyme assembly.
• Dysregulation is associated with developmental and neurological disorders.
• Serves as a biomarker and therapeutic target in precision oncology research.
What Happens During L-serine metabolic process?
De novo biosynthesis via the phosphorylated pathway
In simple terms: Cells can build L-serine from a sugar breakdown intermediate using three enzymes in a row.
The phosphorylated pathway converts the glycolytic intermediate 3-phosphoglycerate to L-serine through three enzymatic steps catalyzed by PHGDH, PSAT1, and PSPH. Evidence indicates that these enzymes can form a multienzyme metabolic assembly that facilitates substrate channeling and efficient L-serine production. This pathway is a major source of L-serine in mammalian cells and is particularly important in tissues with high demand, such as the brain and proliferating tumors.
Uptake and transport of extracellular L-serine
In simple terms: Cells can also import L-serine from outside instead of making it.
L-serine uptake is mediated by amino acid transporters, including SLC1A4. Inhibition of SLC1A4-mediated L-serine uptake has been shown to promote mitochondrial damage in gastric cancer cells, highlighting the importance of transport for cancer cell survival. Transport therefore complements de novo synthesis to maintain intracellular L-serine pools.
Interconversion with glycine and one-carbon metabolism
In simple terms: L-serine can be converted into glycine and donate one-carbon units for many cellular reactions.
Serine hydroxymethyltransferases (SHMT1 and SHMT2) catalyze the reversible conversion of L-serine to glycine, generating one-carbon units that feed folate-mediated one-carbon metabolism. This interconversion links L-serine metabolism to nucleotide synthesis, methylation, and redox homeostasis. The balance between serine and glycine is critical for cell proliferation and is often altered in cancer.
Utilization for glutathione and antioxidant defense
In simple terms: L-serine is used to make cysteine and glutathione, which protect cells from oxidative stress.
L-serine contributes to cysteine synthesis and thereby to glutathione production. Metabolic engineering of the L-serine biosynthetic pathway in Saccharomyces cerevisiae has been shown to improve glutathione production, demonstrating a direct link between L-serine metabolism and antioxidant capacity. This connection is relevant to redox balance in normal and cancer cells.
Serine metabolic reprogramming in disease
In simple terms: In some diseases, cells change how they make and use L-serine to survive or grow.
Serine metabolism is reprogrammed in multiple pathological contexts. In hepatocellular carcinoma, lactylation-driven IGF2BP3-mediated serine metabolism reprogramming and RNA m6A modification promote lenvatinib resistance. In epilepsy, mtDNA leakage promotes neuron-glia crosstalk that induces cGAS-STING-driven neuroinflammation and serine metabolic reprogramming. These examples illustrate how L-serine metabolic process can be rewired under disease conditions.
Key Genes Involved in GO:0006563 L-serine metabolic process
The following genes and proteins are central to L-serine metabolic process, covering biosynthesis, interconversion, transport, and downstream utilization.
| Gene | Major Role | Research Relevance |
|---|---|---|
| PHGDH | First enzyme of the phosphorylated pathway, converts 3-phosphoglycerate to 3-phosphohydroxypyruvate | Target for cancer metabolism and serine biosynthesis studies |
| PSAT1 | Second enzyme, converts 3-phosphohydroxypyruvate to 3-phosphoserine | Component of the multienzyme assembly; linked to proliferation |
| PSPH | Third enzyme, dephosphorylates 3-phosphoserine to L-serine | Completes de novo L-serine biosynthesis |
| SHMT1 | Cytosolic serine hydroxymethyltransferase, interconverts serine and glycine | Links serine metabolism to one-carbon metabolism |
| SHMT2 | Mitochondrial serine hydroxymethyltransferase, interconverts serine and glycine | Important for mitochondrial one-carbon metabolism |
| SLC1A4 | Mediates L-serine uptake | Inhibition promotes mitochondrial damage in gastric cancer |
| IGF2BP3 | RNA-binding protein involved in serine metabolism reprogramming | Linked to lenvatinib resistance in HCC |
| MTHFD1 | One-carbon metabolism enzyme using serine-derived units | Connects serine metabolism to nucleotide synthesis |
| MTHFD2 | Mitochondrial one-carbon metabolism enzyme | Supports proliferation and redox balance |
| GCLC | Glutamate-cysteine ligase catalytic subunit, glutathione synthesis | Downstream of serine-derived cysteine production |
| GCLM | Glutamate-cysteine ligase modifier subunit | Regulates glutathione synthesis |
| CBS | Cystathionine beta-synthase, uses serine for cysteine synthesis | Links serine to transsulfuration |
| CTH | Cystathionase, produces cysteine from cystathionine | Contributes to glutathione production |
| SDS | Serine dehydratase, degrades L-serine to pyruvate | Regulates serine catabolism |
| GCAT | Glycine C-acetyltransferase, uses glycine derived from serine | Links serine to threonine metabolism |
| PHGDH regulators | Transcription factors and signaling pathways controlling PHGDH expression | Potential therapeutic targets |
| ATF4 | Stress-responsive transcription factor regulating serine synthesis genes | Mediates integrated stress response |
| mTOR | Kinase regulating cell growth and serine metabolism | Connects nutrient status to serine pathway |
How Is L-serine metabolic process Regulated?
L-serine metabolic process is regulated at multiple levels. The phosphorylated pathway enzymes PHGDH, PSAT1, and PSPH can assemble into a multienzyme complex, which may provide a mechanism for channeling intermediates and regulating flux. Transcription of serine biosynthesis genes is influenced by nutrient and stress-responsive pathways, including the integrated stress response and mTOR signaling, which coordinate cell growth with amino acid availability. In cancer, oncogenic signals and epitranscriptomic modifications such as m6A can reprogram serine metabolism, as shown by lactylation-driven IGF2BP3-mediated regulation in hepatocellular carcinoma. Additionally, neuron-glia crosstalk and inflammatory signaling can induce serine metabolic reprogramming in the brain.
L-serine metabolic process and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| PHGDH | Cancer metabolism, serine biosynthesis | Knockout or overexpression in cancer cell lines |
| SLC1A4 | Gastric cancer, mitochondrial damage | Knockout or point mutation to block uptake |
| IGF2BP3 | Hepatocellular carcinoma, lenvatinib resistance | Knockdown or knockout in HCC models |
| SHMT2 | One-carbon metabolism, proliferation | Knockout in cancer cell lines |
| PSPH | Serine biosynthesis disorders | Knock-in of patient variants |
Cancer metabolism and therapy resistance
L-serine metabolic process is frequently reprogrammed in cancer. In hepatocellular carcinoma, lactylation-driven IGF2BP3-mediated serine metabolism reprogramming and RNA m6A modification promote lenvatinib resistance, suggesting that targeting this pathway could overcome drug resistance. In gastric cancer, inhibition of SLC1A4-mediated L-serine uptake promotes mitochondrial damage, indicating that serine transport is a vulnerability in some tumors. These findings highlight serine metabolism as a candidate target in precision oncology.
Neurodegeneration and cognitive deficits
Impairment of glycolysis-derived L-serine production in astrocytes contributes to cognitive deficits in Alzheimer's disease models, linking serine metabolism to neurodegeneration. L-serine also links metabolism with neurotransmission, supporting neuronal function and synaptic activity. These studies suggest that maintaining astrocytic L-serine production may be important for brain health.
Neuroinflammation and epilepsy
mtDNA leakage can promote neuron-glia crosstalk that induces epilepsy through cGAS-STING-driven neuroinflammation and serine metabolic reprogramming. This indicates that L-serine metabolic process is not only a metabolic pathway but also a participant in neuroinflammatory signaling, offering potential targets for epilepsy research.
Inborn errors and developmental disorders
L-serine is important in disease and development, and disruptions in its metabolism have been associated with neurological and developmental phenotypes. Understanding the genetic basis of these disorders can inform diagnostic and therapeutic strategies.
From L-serine metabolic process-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of PHGDH affect proliferation? | PHGDH knockout cell line |
| Does a specific point mutation in PSAT1 alter enzyme activity? | PSAT1 point-mutation knock-in |
| Does tagging PSPH reveal its localization? | PSPH tagged knock-in |
| Does overexpression of SLC1A4 increase serine uptake? | SLC1A4 overexpression cell line |
| Does IGF2BP3 mediate lenvatinib resistance? | IGF2BP3 knockout in HCC cells |
| Does SHMT2 deletion alter one-carbon flux? | SHMT2 knockout cells |
How to Study the L-serine metabolic process Process
| Method | What It Measures | Typical Application |
|---|---|---|
| LC-MS metabolomics | Levels of L-serine and related metabolites | Pathway activity in cells and tissues |
| Stable isotope tracing | Flux through serine biosynthesis | De novo serine production |
| RNA-seq | Expression of serine metabolism genes | Cancer and neurodegeneration studies |
| Proteomics | Protein abundance and interactions | Multienzyme assembly analysis |
| Western blot | Protein expression and modifications | Validation of knockout or overexpression |
| Mitochondrial function assay | Mitochondrial membrane potential and ROS | SLC1A4 inhibition studies |
| Glutathione assay | Reduced and oxidized glutathione levels | Redox balance assessment |
Metabolomics and flux analysis
Mass spectrometry-based metabolomics and stable isotope tracing can quantify L-serine and its intermediates, revealing pathway activity and flux. These methods are essential for studying the phosphorylated pathway and its regulation.
Transcriptomics and RNA-seq
RNA sequencing can measure expression of serine metabolism genes such as PHGDH, PSAT1, and PSPH, and identify splicing or epitranscriptomic changes. In cancer, RNA m6A modification has been linked to serine metabolism reprogramming.
Proteomics and enzyme assembly
Proteomic approaches can detect the multienzyme assembly of the phosphorylated pathway and post-translational modifications. This helps understand how enzyme organization influences L-serine production.
Functional assays and imaging
Cell proliferation, mitochondrial function, and oxidative stress assays can test the consequences of perturbing L-serine metabolism. Imaging of mitochondrial damage has been used to study SLC1A4 inhibition in gastric cancer.
How CRISPR Can Be Used to Study GO:0006563 L-serine metabolic process
Knockout
CRISPR knockout of genes such as PHGDH, PSAT1, PSPH, or SLC1A4 can abolish specific steps in L-serine metabolic process, enabling researchers to test their contribution to proliferation, redox balance, and drug resistance.
Point Mutation
Point mutations can be introduced to model enzyme deficiencies or to dissect catalytic residues in PHGDH, PSAT1, or PSPH. Such models help link genotype to metabolic phenotype in serine biosynthesis disorders.
Knock-in
Knock-in of tagged versions of serine pathway enzymes allows visualization and interaction studies. Tagged PSPH or PSAT1 can reveal subcellular localization and assembly of the multienzyme complex.
Overexpression
Overexpression of SLC1A4 or serine biosynthesis enzymes can increase L-serine uptake or production, modeling cancer-associated metabolic reprogramming and testing therapeutic vulnerabilities.
How EDITGENE Supports L-serine metabolic process Research
Researchers studying L-serine metabolic process-related genes often need to determine whether a candidate gene is causally involved in pathway regulation, disease progression, or drug response. Precise genetic models are essential to move from correlation to causation.
Contact EDITGENE today to design your custom CRISPR model for L-serine metabolic process research.
Frequently Asked Questions About L-serine metabolic process
What is L-serine metabolic process?
L-serine metabolic process (GO:0006563) is the set of chemical reactions and pathways involving L-serine, including its biosynthesis, interconversion, transport, and utilization.
What genes are involved in L-serine metabolic process?
Key genes include PHGDH, PSAT1, PSPH, SHMT1, SHMT2, and SLC1A4, among others.
What is the phosphorylated pathway?
The phosphorylated pathway is the main de novo route for L-serine biosynthesis, catalyzed by PHGDH, PSAT1, and PSPH, which can form a multienzyme assembly.
How is L-serine linked to neurotransmission?
L-serine produced by astrocytes supports neuronal function and neurotransmission, linking metabolism with brain signaling.
Why is L-serine metabolism important in cancer?
Cancer cells often reprogram serine metabolism to support growth and resist therapy, as seen in hepatocellular carcinoma and gastric cancer.
What diseases are associated with L-serine metabolic process?
Alzheimer's disease, epilepsy, cancer, and developmental disorders have been linked to altered L-serine metabolism.
How can I study L-serine metabolism in the lab?
Common methods include metabolomics, stable isotope tracing, RNA-seq, proteomics, and CRISPR knockout models.
What is the role of SLC1A4 in L-serine metabolism?
SLC1A4 mediates L-serine uptake, and its inhibition can promote mitochondrial damage in gastric cancer cells.
Does L-serine metabolism affect glutathione production?
Yes, L-serine contributes to cysteine and glutathione synthesis, and engineering its pathway can improve glutathione production.
What CRISPR models are available for L-serine metabolism research?
Knockout, point mutation, knock-in, tagged knock-in, and overexpression models can be generated for genes such as PHGDH, PSAT1, PSPH, and SLC1A4.
Conclusion
GO:0006563 L-serine metabolic process is a central biological process that connects glycolysis, one-carbon metabolism, redox balance, and neurotransmission. Its dysregulation is implicated in cancer, neurodegeneration, and neuroinflammatory diseases, making it a high-value area for functional genomics and therapeutic research. By combining precise CRISPR models with metabolomic and transcriptomic readouts, researchers can dissect the causal roles of serine pathway genes and identify new targets for intervention.
References
- 1. Lu Y et al.. 2024. Lactylation-Driven IGF2BP3-Mediated Serine Metabolism Reprogramming and RNA m6A-Modification Promotes Lenvatinib Resistance in HCC.. Adv Sci (Weinh) 11(46):e2401399 PMID: 39450426
- 2. Le Douce J et al.. 2020. Impairment of Glycolysis-Derived l-Serine Production in Astrocytes Contributes to Cognitive Deficits in Alzheimer's Disease.. Cell Metab 31(3):503-517.e8 PMID: 32130882
- 3. Maugard M et al.. 2021. l-Serine links metabolism with neurotransmission.. Prog Neurobiol 197:101896 PMID: 32798642
- 4. Zhao J et al.. 2025. Skullcapflavone II Inhibits SLC1A4-Mediated L-Serine Uptake and Promotes Mitochondrial Damage in Gastric Cancer.. Adv Sci (Weinh) 12(45):e17225 PMID: 40971730
- 5. Kobayashi J et al.. 2022. Metabolic engineering of the L-serine biosynthetic pathway improves glutathione production in Saccharomyces cerevisiae.. Microb Cell Fact 21(1):153 PMID: 35933377
- 6. Rabattoni V et al.. 2023. The human phosphorylated pathway: a multienzyme metabolic assembly for l-serine biosynthesis.. FEBS J 290(15):3877-3895 PMID: 37012601
- 7. de Koning TJ et al.. 2003. L-serine in disease and development.. Biochem J 371(Pt 3):653-61 PMID: 12534373
- 8. Jiang J et al.. 2026. mtDNA leakage promotes neuron-glia crosstalk to induce epilepsy by cGAS-STING-driven neuroinflammation and serine metabolic reprogramming.. Proc Natl Acad Sci U S A 123(9):e2522313123 PMID: 41734071
