GO:0006094 gluconeogenesis: Metabolic Pathway, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0006094 gluconeogenesis is the biological process that forms glucose from noncarbohydrate precursors such as pyruvate, amino acids and glycerol.
• The liver and kidney are the major gluconeogenic organs, with the kidney contributing substantially to systemic glucose balance.
• Key enzymes include PCK1, PCK2, G6PC, FBP1, PC and PCK2, which are tightly regulated by insulin, glucagon and AMPK.
• Increased hepatic gluconeogenesis is a hallmark of type 2 diabetes mellitus and contributes to hyperglycaemia.
• Gluconeogenesis flux can be tracked using carbon-labelling and metabolomics approaches.
• CRISPR knockout, point-mutation, knock-in and overexpression models enable causal testing of gluconeogenic genes in metabolic disease.
Description
Gluconeogenesis (GO:0006094) is the metabolic pathway that synthesises glucose from noncarbohydrate precursors, including pyruvate, lactate, glycerol and glucogenic amino acids. This process is essential for maintaining blood glucose levels during fasting, prolonged exercise and starvation, when dietary carbohydrate is unavailable. The liver is the primary site of gluconeogenesis, while the kidney also contributes significantly to systemic glucose production, particularly under conditions of acidosis or prolonged fasting. Dysregulation of gluconeogenesis is a central feature of type 2 diabetes mellitus and other metabolic disorders, making it a major research focus. Understanding the enzymes, regulatory mechanisms and flux control of gluconeogenesis is critical for developing therapeutic strategies that target hepatic glucose overproduction. This article provides a research-grade overview of GO:0006094, covering its definition, molecular components, key genes, disease links and CRISPR-based research methods.
gluconeogenesis At A Glance
| GO ID | GO:0006094 |
|---|---|
| GO term | gluconeogenesis |
| Ontology | biological_process |
| Synonym | glucose biosynthesis; glucose biosynthetic process |
| Major function | Formation of glucose from noncarbohydrate precursors such as pyruvate, amino acids and glycerol |
| Major organs | Liver and kidney |
| Key enzymes | PCK1, PCK2, G6PC, FBP1, PC, PCK2 |
| Regulatory hormones | Insulin, glucagon, glucocorticoids |
| Disease relevance | Type 2 diabetes mellitus, metabolic syndrome, cancer cachexia |
What Is GO:0006094?
According to the Gene Ontology, GO:0006094 gluconeogenesis is defined as the formation of glucose from noncarbohydrate precursors, such as pyruvate, amino acids and glycerol. It is a biological process that encompasses the series of enzymatic reactions reversing glycolysis, using substrates like lactate, glycerol and glucogenic amino acids to synthesise glucose. This pathway is distinct from glycogenolysis, which releases glucose from glycogen stores, and is essential for maintaining euglycaemia during fasting.
Why Is gluconeogenesis Important in Cell Biology?
Gluconeogenesis is vital for systemic glucose homeostasis, ensuring that the brain and other glucose-dependent tissues receive a continuous supply of glucose during fasting. Its dysregulation is directly implicated in type 2 diabetes mellitus, where increased hepatic gluconeogenesis contributes to fasting hyperglycaemia. The pathway is also relevant to cancer metabolism, renal disease and metabolic syndrome, making it a key target for therapeutic intervention. Research into gluconeogenesis informs the development of antidiabetic drugs such as metformin, which suppresses hepatic glucose production.
• Maintains blood glucose during fasting and starvation.
• Dysregulated in type 2 diabetes mellitus, contributing to hyperglycaemia.
• Kidney gluconeogenesis is an underestimated contributor to systemic glucose balance.
• Regulated by insulin, glucagon and AMPK signalling pathways.
• Provides carbon for glucose synthesis from lactate, glycerol and amino acids.
• Target for antidiabetic therapies such as metformin.
• Involved in cancer metabolic reprogramming and cachexia.
• Essential for renal ammonia metabolism and acid-base balance.
• Studied using CRISPR knockout and knock-in models.
• Flux can be quantified using stable isotope tracing.
What Happens During gluconeogenesis?
Substrate supply and precursor uptake
In simple terms: The body gathers raw materials like lactate, glycerol and amino acids to make new glucose.
Gluconeogenesis begins with the uptake of noncarbohydrate precursors, including lactate from muscle and red blood cells, glycerol from adipose tissue lipolysis, and glucogenic amino acids from protein breakdown. These substrates are transported to the liver and kidney, where they enter the gluconeogenic pathway. Carbon tracking studies have shown that lactate and amino acids are major contributors to glucose production in vivo.
Conversion of pyruvate to phosphoenolpyruvate
In simple terms: Pyruvate is converted into a molecule that can enter the glucose-making assembly line.
The first committed step involves the conversion of pyruvate to oxaloacetate by pyruvate carboxylase (PC), followed by the conversion of oxaloacetate to phosphoenolpyruvate (PEP) by phosphoenolpyruvate carboxykinase (PCK1 in cytosol, PCK2 in mitochondria). This step bypasses the irreversible glycolytic step catalysed by pyruvate kinase. PCK1 and PCK2 are key regulatory enzymes whose expression is induced by glucagon and suppressed by insulin.
Reversal of glycolysis and fructose-1,6-bisphosphatase
In simple terms: The pathway runs glycolysis in reverse, using special enzymes to bypass irreversible steps.
Most gluconeogenic reactions are reversible glycolytic reactions. The irreversible step catalysed by phosphofructokinase-1 is bypassed by fructose-1,6-bisphosphatase 1 (FBP1), which dephosphorylates fructose-1,6-bisphosphate to fructose-6-phosphate. This enzyme is a key control point regulated by AMP, fructose-2,6-bisphosphate and hormonal signals.
Glucose-6-phosphatase and final glucose release
In simple terms: The final step releases free glucose into the blood.
The last step of gluconeogenesis is the hydrolysis of glucose-6-phosphate to free glucose by glucose-6-phosphatase (G6PC), which is expressed in the liver and kidney. This enzyme is essential for releasing glucose into the circulation and is a target of insulin regulation. Deficiency of G6PC causes glycogen storage disease type Ia, highlighting its critical role.
Renal gluconeogenesis and systemic integration
In simple terms: The kidneys also make glucose, especially during long fasts or acidosis.
The kidney contributes significantly to systemic glucose production, particularly during prolonged fasting and metabolic acidosis. Renal gluconeogenesis uses similar enzymes but is regulated differently, with glutamine serving as a major substrate. This organ-specific regulation is important for understanding whole-body glucose homeostasis.
Key Genes Involved in GO:0006094 gluconeogenesis
The following genes encode enzymes and regulators that are central to gluconeogenesis (GO:0006094).
| Gene | Major Role | Research Relevance |
|---|---|---|
| PCK1 | Cytosolic phosphoenolpyruvate carboxykinase; converts oxaloacetate to PEP | Rate-limiting enzyme; target for diabetes research |
| PCK2 | Mitochondrial phosphoenolpyruvate carboxykinase; supports PEP formation | Isoform-specific roles in gluconeogenesis and cancer |
| G6PC | Glucose-6-phosphatase; final step of glucose release | Mutations cause glycogen storage disease type Ia |
| FBP1 | Fructose-1,6-bisphosphatase; bypasses PFK-1 step | Regulated by AMP and fructose-2,6-bisphosphate |
| PC | Pyruvate carboxylase; converts pyruvate to oxaloacetate | Essential for gluconeogenesis from lactate and amino acids |
| PCK1 | Phosphoenolpyruvate carboxykinase 1 | Insulin-regulated; key control point |
| G6PC | Glucose-6-phosphatase catalytic subunit | Target of metformin and insulin |
| FBP1 | Fructose-1,6-bisphosphatase 1 | Tumour suppressor in some cancers |
| PC | Pyruvate carboxylase | Anaplerotic role in TCA cycle |
| PCK2 | Phosphoenolpyruvate carboxykinase 2 | Mitochondrial isoform; cancer metabolism |
| G6PC | Glucose-6-phosphatase | Renal gluconeogenesis |
| FBP1 | Fructose-1,6-bisphosphatase | Regulated by AMPK |
| PCK1 | PEPCK-C | Hepatic gluconeogenesis |
| G6PC | G6Pase | Glycogen storage disease |
| PC | Pyruvate carboxylase | Mitochondrial metabolism |
| FBP1 | FBPase | Gluconeogenic flux control |
| PCK2 | PEPCK-M | Renal and cancer metabolism |
| G6PC | Glucose-6-phosphatase | Type 2 diabetes target |
How Is gluconeogenesis Regulated?
Gluconeogenesis is tightly regulated by hormonal and nutritional signals. Insulin suppresses gluconeogenic gene expression, including PCK1 and G6PC, through PI3K/Akt signalling. Glucagon and glucocorticoids induce these genes during fasting. AMPK inhibits liver gluconeogenesis, although the precise mechanisms remain debated. AMPK phosphorylates and inhibits acetyl-CoA carboxylase, and may also regulate transcription of gluconeogenic enzymes. Fructose-2,6-bisphosphate is a potent allosteric regulator of FBP1 and PFK-1, integrating glycolytic and gluconeogenic flux. Renal gluconeogenesis is regulated by acidosis, potassium and glutamine availability.
gluconeogenesis and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| PCK1 | Type 2 diabetes mellitus | Liver-specific KO mouse; CRISPR KO in HepG2 cells |
| G6PC | Glycogen storage disease type Ia | Point-mutation knock-in in iPSCs; KO in hepatocytes |
| FBP1 | Cancer (HCC, RCC) | KO in cancer cell lines; overexpression in normal cells |
| PCK2 | Cancer metabolism | KO in cancer cell lines; metabolic flux analysis |
| PC | Metabolic syndrome | Liver-specific KO; CRISPR point mutation in PC gene |
Type 2 diabetes mellitus and hepatic gluconeogenesis
Increased hepatic gluconeogenesis is a major contributor to fasting hyperglycaemia in type 2 diabetes mellitus. Insulin resistance impairs the suppression of gluconeogenic gene expression, leading to excessive glucose production. Therapeutic strategies targeting PCK1, G6PC and FBP1 are under investigation.
Renal gluconeogenesis and kidney disease
The kidney contributes to systemic glucose balance, and its dysregulation is implicated in diabetic nephropathy and acidosis. Renal gluconeogenesis is an underestimated factor in glucose homeostasis, particularly in chronic kidney disease.
Cancer metabolism and FBP1
FBP1, a key gluconeogenic enzyme, is downregulated in several cancers, including hepatocellular carcinoma and renal cell carcinoma, where its loss promotes Warburg effect and tumour growth. PCK2 also supports cancer cell metabolism under metabolic stress.
From gluconeogenesis-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does PCK1 loss reduce hepatic glucose production? | Liver-specific PCK1 knockout mouse |
| Does a G6PC point mutation cause glycogen storage disease? | CRISPR knock-in of patient mutation in iPSCs |
| Can FBP1 overexpression suppress tumour growth? | FBP1 overexpression in cancer cell lines |
| What is the role of PCK2 in cancer metabolism? | PCK2 knockout in cancer cells |
| How does insulin regulate G6PC transcription? | Tagged knock-in of G6PC promoter; ChIP-seq |
| Does AMPK regulate gluconeogenesis in vivo? | AMPK knockout mouse; CRISPR KO in hepatocytes |
How to Study the gluconeogenesis Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Stable isotope tracing | Gluconeogenic flux | In vivo and in vitro glucose production |
| RNA-seq | Gene expression | Hormonal regulation of PCK1, G6PC |
| CRISPR knockout screening | Gene function | Discovery of gluconeogenesis regulators |
| Metabolomics | Metabolite levels | Pathway intermediate quantification |
| ChIP-seq | Transcription factor binding | Insulin regulation of G6PC promoter |
| Western blot | Protein expression | Enzyme abundance |
| Glucose production assay | Glucose output | Hepatocyte glucose production |
| Seahorse assay | Glycolysis and respiration | Metabolic phenotype |
Stable isotope tracing and metabolomics
Stable isotope tracing with 13C-labelled substrates (lactate, glycerol, amino acids) allows quantification of gluconeogenic flux in cells and animals. Metabolomics can measure intermediate pools and pathway activity.
CRISPR screening for gluconeogenesis regulators
Genome-wide CRISPR knockout screens can identify genes that regulate gluconeogenic gene expression or glucose production. These screens are useful for discovering novel regulators of PCK1 and G6PC.
Transcriptomics and RNA-seq
RNA-seq measures expression of gluconeogenic enzymes under different hormonal and nutritional conditions. It is widely used to study insulin and glucagon regulation.
Proteomics and post-translational modification analysis
Proteomics can quantify enzyme abundance and phosphorylation status of key gluconeogenic regulators such as PCK1 and FBP1.
How CRISPR Can Be Used to Study GO:0006094 gluconeogenesis
Knockout
CRISPR knockout of PCK1, G6PC or FBP1 in liver cell lines or primary hepatocytes can abolish gluconeogenic flux, enabling causal testing of their role in glucose production. Liver-specific knockout mice are used to study systemic glucose homeostasis.
Point Mutation
Point mutations in G6PC cause glycogen storage disease type Ia. CRISPR point-mutation models can recapitulate patient mutations in iPSCs or hepatocytes to study enzyme dysfunction.
Knock-in
Knock-in of tagged PCK1 or G6PC allows tracking of protein localisation and interactions. Knock-in of reporter genes under gluconeogenic promoters enables live-cell imaging of pathway activity.
Overexpression
Overexpression of FBP1 or PCK2 in cancer cells can suppress tumour growth or alter metabolic flux, providing insights into their tumour suppressor functions.
How EDITGENE Supports gluconeogenesis Research
Researchers studying gluconeogenesis-related genes often need to determine whether a candidate gene is causally involved in glucose production, metabolic disease or cancer. EDITGENE provides CRISPR-based cell models and screening services to accelerate this research.
Contact EDITGENE today to design your custom CRISPR model for gluconeogenesis research.
Frequently Asked Questions About gluconeogenesis
What is gluconeogenesis GO:0006094?
Gluconeogenesis (GO:0006094) is the biological process of forming glucose from noncarbohydrate precursors such as pyruvate, amino acids and glycerol.
What genes are involved in gluconeogenesis?
Key genes include PCK1, PCK2, G6PC, FBP1 and PC, which encode enzymes that catalyse the pathway.
Why is gluconeogenesis important in diabetes?
Increased hepatic gluconeogenesis contributes to fasting hyperglycaemia in type 2 diabetes mellitus.
How is gluconeogenesis regulated?
It is regulated by insulin, glucagon, AMPK and allosteric effectors such as fructose-2,6-bisphosphate.
What is the role of PCK1 in gluconeogenesis?
PCK1 encodes cytosolic PEPCK, which converts oxaloacetate to phosphoenolpyruvate, a rate-limiting step.
Does the kidney perform gluconeogenesis?
Yes, the kidney contributes significantly to systemic glucose production, especially during prolonged fasting.
What diseases are linked to gluconeogenesis?
Type 2 diabetes, glycogen storage disease type Ia, cancer and metabolic syndrome.
How can I study gluconeogenesis in the lab?
Stable isotope tracing, CRISPR knockout models, RNA-seq and glucose production assays are commonly used.
What is the difference between gluconeogenesis and glycogenolysis?
Gluconeogenesis synthesises glucose from noncarbohydrate precursors, while glycogenolysis releases glucose from glycogen.
Can CRISPR be used to study gluconeogenesis?
Yes, CRISPR knockout, knock-in and overexpression models enable causal testing of gluconeogenic genes.
Conclusion
Gluconeogenesis (GO:0006094) is a fundamental metabolic pathway that maintains blood glucose during fasting and is dysregulated in type 2 diabetes and other diseases. Its key enzymes, including PCK1, G6PC and FBP1, are tightly regulated by insulin, glucagon and AMPK. CRISPR-based models provide powerful tools to dissect the causal roles of these genes in metabolic disease, and EDITGENE offers comprehensive services to support this research.
References
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- 2. Barroso E et al.. 2024. Increased hepatic gluconeogenesis and type 2 diabetes mellitus.. Trends Endocrinol Metab 35(12):1062-1077 PMID: 38816269
- 3. Hatting M et al.. 2018. Insulin regulation of gluconeogenesis.. Ann N Y Acad Sci 1411(1):21-35 PMID: 28868790
- 4. Yu S et al.. 2021. Phosphoenolpyruvate carboxykinase in cell metabolism: Roles and mechanisms beyond gluconeogenesis.. Mol Metab 53:101257 PMID: 34020084
- 5. Shah AM et al.. 2020. Tracking the carbons supplying gluconeogenesis.. J Biol Chem 295(42):14419-14429 PMID: 32817317
- 6. Johanns M et al.. 2023. AMPK inhibits liver gluconeogenesis: fact or fiction?. Biochem J 480(1):105-125 PMID: 36637190
- 7. Legouis D et al.. 2022. Renal gluconeogenesis: an underestimated role of the kidney in systemic glucose metabolism.. Nephrol Dial Transplant 37(8):1417-1425 PMID: 33247734
- 8. Schoolwerth AC et al.. 1988. Renal gluconeogenesis.. Miner Electrolyte Metab 14(6):347-61 PMID: 3068502
