GO:2001069 glycogen binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:2001069 glycogen binding is a molecular function defined as binding to glycogen, the branched glucose polymer also called animal starch or liver starch.
• The best-characterized glycogen-binding proteins include STBD1, the AMPK beta subunits, glycogen phosphorylase, laforin, and starch/glycogen-binding domain (SBD) proteins [1,3,4,5,6].
• Glycogen binding is not passive: it directly regulates gluconeogenesis through an AMPK/CRTC2 axis in liver.
• Loss of AMPK-glycogen binding destabilizes AMPK and disrupts whole-body metabolism.
• STBD1 acts as an autophagy receptor for glycogen and mediates crosstalk between glycogen and lipid droplets, with roles in clear cell renal cell carcinoma [1,7,8].
• CRISPR knockout, point-mutation, knock-in, and overexpression models are the core tools for dissecting glycogen-binding protein function.
Description
Glycogen is a highly branched polymer of glucose that serves as the principal storage carbohydrate in animals, often called animal starch or liver starch. The molecular function GO:2001069, glycogen binding, describes the selective, non-covalent interaction of a protein with glycogen [1,4]. This function is central to how cells sense, store, and mobilize glucose, because proteins that bind glycogen are positioned to regulate its synthesis, degradation, and autophagic turnover [1,5]. Classic work by Madsen and Cori established that phosphorylase binds glycogen as a prerequisite for phosphorolysis, making glycogen binding one of the oldest biochemically defined protein-carbohydrate interactions. Modern research has expanded the repertoire of glycogen-binding proteins far beyond enzymes. STBD1 (starch-binding domain-containing protein 1) is a glycogen-binding autophagy receptor that targets glycogen for lysosomal degradation [1,8]. The AMPK beta subunits contain carbohydrate-binding modules that anchor AMPK to glycogen particles, coupling energy sensing to glycogen status. Hepatic glycogen itself directly regulates gluconeogenesis through an AMPK/CRTC2 axis, showing that glycogen binding is a signaling event, not merely a metabolic one. For researchers, GO:2001069 provides a precise annotation axis for interrogating how cells decode glycogen stores into metabolic, autophagic, and transcriptional outputs [1,2,5].
glycogen binding At A Glance
| GO ID | GO:2001069 |
|---|---|
| GO term | glycogen binding |
| Ontology | molecular_function |
| Synonym | animal starch binding; liver starch binding |
| Definition | Binding to glycogen. |
| Major function | Non-covalent recognition of glycogen particles by enzymes, regulatory subunits, and autophagy receptors |
| Representative proteins | STBD1, PRKAB1/PRKAB2 (AMPK beta subunits), PYGM/PYGL, EPM2A (laforin), SBD-containing proteins |
| Related processes | Glycogen metabolism, gluconeogenesis regulation, glycophagy, energy sensing |
| Disease relevance | Lafora disease, metabolic disorders, clear cell renal cell carcinoma |
What Is GO:2001069?
In our own words, GO:2001069 glycogen binding is the molecular function of selectively and non-covalently interacting with glycogen, a branched polymer of glucose that functions as an energy storage molecule in animals. The term is a child of carbohydrate binding and is synonymous with animal starch binding and liver starch binding. It is assigned to proteins that physically associate with glycogen particles, including enzymes such as glycogen phosphorylase, scaffolding and regulatory proteins such as the AMPK beta subunits, and autophagy receptors such as STBD1 [1,3,4,8].
Why Is glycogen binding Important in Cell Biology?
Glycogen binding matters because it converts a storage polymer into a signaling and trafficking hub. Proteins that bind glycogen can sense its abundance, regulate its synthesis and breakdown, and route it to lysosomes for degradation [1,2,5,8]. In liver, glycogen binding by AMPK-containing complexes directly suppresses gluconeogenesis through CRTC2, linking nutrient storage to blood glucose control. In muscle and other tissues, loss of AMPK-glycogen binding destabilizes AMPK and disrupts metabolism, showing that the interaction is required for metabolic homeostasis. In disease, defective glycogen handling underlies Lafora disease, and STBD1-mediated glycogen-lipid droplet crosstalk contributes to clear cell renal cell carcinoma biology [5,7]. Because glycogen binding is a discrete molecular function, it is an attractive target for CRISPR-based functional dissection.
• Defines how cells physically recognize and sense glycogen stores [1,4].
• Regulates gluconeogenesis through an AMPK/CRTC2 axis in liver.
• Required for AMPK stability and normal whole-body metabolism.
• Underlies selective autophagy of glycogen (glycophagy) via STBD1 [1,8].
• Implicated in Lafora disease through laforin and glycogen phosphorylation.
• Connects glycogen to lipid droplet biology in clear cell renal cell carcinoma.
• Provides a conserved protein-carbohydrate interaction module across microbes, plants, and animals.
• Offers a tractable target for CRISPR knockout, knock-in, and point-mutation studies [1,3].
What Happens During glycogen binding?
Recognition of the glycogen particle
In simple terms: Proteins find and stick to glycogen granules.
Glycogen binding begins with recognition of the branched glucose polymer surface. Classic studies showed that glycogen phosphorylase binds glycogen as a prerequisite for catalysis, establishing the founding example of this function. Structural and evolutionary analyses have identified non-catalytic starch/glycogen-binding domains (SBDs) that mediate this recognition across microbes, plants, and animals. In animals, STBD1 uses a starch-binding domain to engage glycogen particles.
Anchoring of regulatory complexes
In simple terms: Binding holds regulatory machines next to the glycogen store.
Beyond enzymes, glycogen binding anchors regulatory complexes to glycogen. The AMPK beta subunits contain carbohydrate-binding modules that localize AMPK to glycogen particles, and genetic loss of this binding destabilizes AMPK and disrupts metabolism. This anchoring positions the energy sensor where it can monitor and respond to glycogen status.
Signal transduction to transcription
In simple terms: The binding event sends a message to the nucleus.
Glycogen binding is not merely structural; it feeds into signaling. Hepatic glycogen directly regulates gluconeogenesis through an AMPK/CRTC2 axis in mice, meaning the glycogen-bound state is translated into transcriptional control of glucose production.
Autophagic targeting of glycogen
In simple terms: Binding tags glycogen for recycling in lysosomes.
STBD1 functions as an autophagy receptor for glycogen, mediating selective glycophagy. The molecular mechanism of STBD1-mediated selective autophagy of glycogen has been decoded, showing how glycogen binding routes the polymer to lysosomal degradation [1,8].
Crosstalk with lipid droplets
In simple terms: Glycogen binding can also influence fat storage.
STBD1 mediates crosstalk between glycogen and lipid droplets in clear cell renal cell carcinoma, indicating that glycogen-binding proteins can coordinate carbohydrate and lipid storage compartments.
Key Genes Involved in GO:2001069 glycogen binding
The following genes encode proteins with demonstrated or strongly implicated glycogen-binding activity, spanning enzymes, regulatory subunits, and autophagy receptors.
| Gene | Major Role | Research Relevance |
|---|---|---|
| STBD1 | Glycogen-binding autophagy receptor mediating glycophagy | Central to selective glycogen autophagy and glycogen-lipid crosstalk [1,7,8] |
| PRKAB1 | AMPK beta-1 subunit with carbohydrate-binding module | Loss of glycogen binding destabilizes AMPK |
| PRKAB2 | AMPK beta-2 subunit with carbohydrate-binding module | Tissue-specific AMPK-glycogen anchoring |
| PYGM | Muscle glycogen phosphorylase that binds glycogen | Founding example of glycogen binding by an enzyme |
| PYGL | Liver glycogen phosphorylase that binds glycogen | Hepatic glycogen mobilization |
| PYGB | Brain glycogen phosphorylase that binds glycogen | Brain glycogen metabolism |
| EPM2A | Laforin, a glycogen-binding phosphatase | Lafora disease and glycogen phosphorylation |
| EPM2B | Malin, partner of laforin in glycogen regulation | Lafora disease biology |
| PPP1R3A | Protein phosphatase 1 regulatory subunit targeting glycogen | Glycogen synthase regulation |
| PPP1R3B | Liver-specific PP1 regulatory subunit | Hepatic glycogen metabolism |
| GYS1 | Muscle glycogen synthase | Glycogen synthesis and storage |
| GYS2 | Liver glycogen synthase | Hepatic glycogen synthesis |
| GYG1 | Glycogenin-1, primer for glycogen synthesis | Glycogen particle initiation |
| GYG2 | Glycogenin-2 | Glycogen particle initiation |
| CRTC2 | CREB-regulated transcription coactivator 2 | Downstream effector of glycogen-AMPK signaling |
| STBD1-related SBD proteins | Starch/glycogen-binding domain family | Evolutionary conservation of glycogen binding |
How Is glycogen binding Regulated?
Glycogen binding is regulated at multiple levels. The abundance and branching of glycogen itself determines substrate availability for binding proteins [2,5]. AMPK beta-subunit carbohydrate binding is required for AMPK stability, so loss of binding reduces AMPK levels and disrupts metabolism. Glycogen phosphorylation by laforin modulates glycogen structure and its handling, linking post-translational glycogen modification to Lafora disease. STBD1-mediated glycophagy is regulated as an autophagy receptor pathway, coupling glycogen binding to lysosomal degradation [1,8]. Hepatic glycogen levels feed back on gluconeogenesis through AMPK/CRTC2, providing transcriptional regulation of glucose production.
glycogen binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| EPM2A | Lafora disease | Knockout and point-mutation models in neurons |
| PRKAB1/PRKAB2 | Metabolic disorder via AMPK destabilization | Knock-in of binding-deficient AMPK beta |
| STBD1 | Clear cell renal cell carcinoma; glycophagy | Knockout and overexpression in renal cell lines [1,7,8] |
| PYGL | Hepatic glycogen storage dysregulation | Liver-specific knockout |
| CRTC2 | Dysregulated gluconeogenesis | Knockout and phospho-mutant knock-in |
Lafora disease and glycogen phosphorylation
Lafora disease is a progressive myoclonus epilepsy caused by defects in glycogen phosphorylation and handling. Laforin (EPM2A) is a glycogen-binding phosphatase, and its dysfunction leads to accumulation of abnormal, hyperphosphorylated glycogen that forms Lafora bodies. This directly links glycogen binding and glycogen modification to neurodegeneration.
Metabolic disorders and AMPK-glycogen binding
Genetic loss of AMPK-glycogen binding destabilizes AMPK and disrupts metabolism, indicating that this molecular function is required for normal energy homeostasis. Because hepatic glycogen directly regulates gluconeogenesis through AMPK/CRTC2, defects in glycogen binding can contribute to dysregulated blood glucose.
Clear cell renal cell carcinoma
STBD1 mediates crosstalk between glycogen and lipid droplets in clear cell renal cell carcinoma, a tumor type characterized by glycogen and lipid accumulation. This positions glycogen-binding proteins as modulators of tumor metabolism.
Glycophagy and lysosomal storage
STBD1 is an autophagy receptor for glycogen, and the molecular mechanism of STBD1-mediated selective autophagy of glycogen has been decoded [1,8]. Defects in this pathway impair glycogen clearance and connect glycogen binding to lysosomal degradation biology.
From glycogen binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Is the glycogen-binding domain required for protein stability? | Knockout and binding-deficient point-mutation knock-in |
| Does glycogen binding regulate gluconeogenic transcription? | Liver-specific knockout with CRTC2 readout |
| Is STBD1 required for glycophagy? | STBD1 knockout with autophagy flux assays [1,8] |
| Does glycogen binding affect lipid droplet crosstalk? | STBD1 overexpression and knockout in ccRCC cells |
| How does laforin glycogen binding prevent Lafora bodies? | EPM2A point-mutation knock-in |
| Is the SBD sufficient for glycogen targeting? | Tagged knock-in and live imaging [1,6] |
How to Study the glycogen binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Glycogen co-pelleting assay | Direct protein-glycogen binding | Validate SBD function [4,6] |
| CRISPR knockout | Loss-of-function phenotype | Test requirement for glycogen binding |
| Point-mutation knock-in | Binding-deficient vs wild-type | Separate binding from catalysis |
| Tagged knock-in imaging | Subcellular localization | Track glycogen particle targeting |
| Autophagy flux assay | Glycophagy activity | STBD1 receptor function |
| Gluconeogenesis assay | Hepatic glucose production | AMPK/CRTC2 axis |
| Lipid droplet co-localization | Glycogen-lipid crosstalk | ccRCC metabolism |
| Phosphatase assay | Glycogen dephosphorylation | Laforin function |
Biochemical glycogen-binding assays
Recombinant proteins or lysates can be incubated with glycogen and pelleted to measure binding, an approach rooted in classic phosphorylase-glycogen binding experiments. Starch/glycogen-binding domain constructs can be used to map the minimal binding region.
Genetic loss- and gain-of-function
CRISPR knockout of glycogen-binding proteins, combined with binding-deficient point mutants, distinguishes binding-dependent from catalytic functions. Overexpression of STBD1 or laforin variants tests sufficiency for glycogen targeting and clearance [1,5].
Metabolic and transcriptional readouts
Gluconeogenesis can be assessed in liver models to test the AMPK/CRTC2 axis downstream of glycogen binding. AMPK stability and activity are measured to determine whether glycogen binding is required for kinase integrity.
Imaging and autophagy flux
Tagged glycogen-binding proteins can be imaged to track glycogen particles and autophagic targeting [1,8]. Lipid droplet co-localization assays reveal glycogen-lipid crosstalk.
How CRISPR Can Be Used to Study GO:2001069 glycogen binding
Knockout
CRISPR knockout of STBD1, PRKAB1/PRKAB2, EPM2A, or PYGL removes the glycogen-binding protein entirely, revealing its requirement in glycogen turnover, AMPK stability, and gluconeogenesis [1,3,5].
Point Mutation
Point mutations that disrupt the carbohydrate-binding module allow separation of glycogen binding from other protein functions, as shown for AMPK beta subunits where loss of binding destabilizes AMPK.
Knock-in
Knock-in of tagged or disease-associated variants, such as laforin mutants, enables tracking of glycogen binding in situ and modeling of Lafora disease.
Overexpression
Overexpression of STBD1 or glycogen-binding domain constructs tests sufficiency for glycogen targeting, glycophagy, and lipid droplet crosstalk in cancer and metabolic models [1,7,8].
How EDITGENE Supports glycogen binding Research
Researchers studying glycogen binding-related genes often need to determine whether a candidate gene is causally involved in glycogen recognition, turnover, or downstream signaling. Establishing causality requires precise genetic models that isolate binding from catalysis and that report on glycogen particle dynamics in living cells.
Contact EDITGENE today to design your custom CRISPR model for glycogen binding research.
Frequently Asked Questions About glycogen binding
What is GO:2001069 glycogen binding?
GO:2001069 glycogen binding is a molecular function defined as binding to glycogen, a branched glucose storage polymer also called animal starch or liver starch [1,4].
What genes are involved in glycogen binding?
Key genes include STBD1, PRKAB1, PRKAB2, PYGM, PYGL, PYGB, EPM2A, EPM2B, PPP1R3A, PPP1R3B, GYS1, GYS2, GYG1, and GYG2 [1,3,4,5].
How does glycogen binding regulate metabolism?
Hepatic glycogen directly regulates gluconeogenesis through an AMPK/CRTC2 axis, and loss of AMPK-glycogen binding destabilizes AMPK and disrupts metabolism [2,3].
What is the role of STBD1 in glycogen binding?
STBD1 is a glycogen-binding autophagy receptor that mediates selective autophagy of glycogen and crosstalk between glycogen and lipid droplets [1,7,8].
Is glycogen binding involved in Lafora disease?
Yes. Laforin (EPM2A) is a glycogen-binding phosphatase, and defects in glycogen phosphorylation cause Lafora bodies in Lafora disease.
What is glycophagy?
Glycophagy is the selective autophagic degradation of glycogen, mediated by the glycogen-binding receptor STBD1 [1,8].
Which domains mediate glycogen binding?
Starch/glycogen-binding domains (SBDs) and carbohydrate-binding modules mediate glycogen recognition across microbes, plants, and animals.
How can I study glycogen binding with CRISPR?
Knockout removes the protein, point mutations disrupt binding, knock-in adds tags or disease variants, and overexpression tests sufficiency [1,3,5].
Does glycogen binding affect cancer?
STBD1-mediated glycogen-lipid droplet crosstalk has been implicated in clear cell renal cell carcinoma.
What methods measure glycogen binding?
Glycogen co-pelleting assays, autophagy flux assays, imaging of tagged proteins, and metabolic readouts such as gluconeogenesis assays [2,4,8].
Conclusion
GO:2001069 glycogen binding is a discrete molecular function that connects glycogen storage to enzyme catalysis, energy sensing, autophagy, and transcriptional control. From the classic phosphorylase-glycogen interaction to modern STBD1-mediated glycophagy and AMPK/CRTC2 signaling, glycogen-binding proteins are central to metabolic homeostasis and disease [1,2,3,4,5,8]. CRISPR-based knockout, point-mutation, knock-in, and overexpression models provide the precision needed to dissect these functions and to translate them into therapeutic insight.
References
- 1. Tang Q et al.. 2023. Glycogen-binding protein STBD1: Molecule and role in pathophysiology.. J Cell Physiol 238(9):2010-2025 PMID: 37435888
- 2. Zhang B et al.. 2025. Hepatic glycogen directly regulates gluconeogenesis through an AMPK/CRTC2 axis in mice.. J Clin Invest 135(11) PMID: 40454488
- 3. Hoffman NJ et al.. 2020. Genetic loss of AMPK-glycogen binding destabilises AMPK and disrupts metabolism.. Mol Metab 41:101048 PMID: 32610071
- 4. MADSEN NB et al.. 1958. The binding of glycogen and phosphorylase.. J Biol Chem 233(6):1251-6 PMID: 13610823
- 5. Roach PJ. 2015. Glycogen phosphorylation and Lafora disease.. Mol Aspects Med 46:78-84 PMID: 26278984
- 6. Janeček Š et al.. 2011. Structural and evolutionary aspects of two families of non-catalytic domains present in starch and glycogen binding proteins from microbes, plants and animals.. Enzyme Microb Technol 49(5):429-40 PMID: 22112614
- 7. Wang H et al.. 2025. STBD1 mediates the crosstalk between glycogen and lipid droplets in clear cell renal cell carcinoma.. Cell Rep 44(10):116429 PMID: 41105508
- 8. Zhang Y et al.. 2024. Decoding the molecular mechanism of selective autophagy of glycogen mediated by autophagy receptor STBD1.. Proc Natl Acad Sci U S A 121(37):e2402817121 PMID: 39236246
