GO:0005176 ErbB-2 class receptor binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0005176 ErbB-2 class receptor binding is a molecular function defined as binding to the protein-tyrosine kinase receptor Neu/ErbB-2/HER2.
• The term covers ligand-like molecules and engineered binders that physically associate with the HER2/Neu/ErbB-2 receptor ectodomain.
• Affibody molecules such as Z(HER2:342) and Z(HER2:2395) are validated experimental binders of the ErbB-2 class receptor and are widely used as imaging probes.
• ErbB-2 class receptor binding is central to HER2-targeted molecular imaging, including SPECT and PET tracer development.
• The function is studied with radiolabeled and fluorescent binders, including 99mTc-, 111In- and Cy5.5-conjugated constructs.
• Because HER2 is a major oncogenic receptor, precise binding tools enable target validation, diagnostic imaging and therapeutic development.
Description
GO:0005176 ErbB-2 class receptor binding is a molecular function term describing the binding of a molecule to the protein-tyrosine kinase receptor Neu/ErbB-2/HER2. In the QuickGO ontology, this function is defined as binding to a protein-tyrosine kinase receptor Neu/ErbB-2/HER2, and it is classified under molecular_function. The term is closely associated with ligand-like interactions at the HER2 receptor ectodomain, and it is experimentally studied using engineered binding proteins such as Affibody molecules. Researchers care about this term because HER2/ErbB-2 is a clinically important receptor tyrosine kinase and a major target in oncology imaging and therapy. Experimental binders that satisfy the GO:0005176 definition, including Z(HER2:342) and Z(HER2:2395) Affibody constructs, have been radiolabeled and characterized for receptor-specific targeting. These reagents allow direct interrogation of ErbB-2 class receptor binding in living systems and provide a functional readout of receptor accessibility and expression. The term also serves as an annotation hub for interpreting binding assays, imaging studies and structural studies focused on the HER2/Neu receptor. Because the definition is receptor-centric, any molecule that binds Neu/ErbB-2/HER2 can be annotated to GO:0005176, including natural ligands, engineered Affibody ligands and fluorescent or radiolabeled derivatives. This makes the term useful for both basic receptor biology and translational molecular imaging research.
ErbB-2 class receptor binding At A Glance
| GO ID | GO:0005176 |
|---|---|
| GO term | ErbB-2 class receptor binding |
| Ontology | molecular_function |
| Definition | Binding to a protein-tyrosine kinase receptor Neu/ErbB-2/HER2 |
| Synonym | ErbB-2 class receptor ligand; HER2 receptor binding; HER2 receptor ligand; Neu receptor binding; Neu receptor ligand |
| Major function | Physical association with the HER2/Neu/ErbB-2 receptor ectodomain |
| Example binders | Affibody molecules Z(HER2:342) and Z(HER2:2395) |
| Common assays | Radiolabeled binding, fluorescent imaging, SPECT/PET tracer characterization |
| Disease relevance | HER2-positive cancers and receptor-targeted imaging |
What Is GO:0005176?
In simple terms, GO:0005176 ErbB-2 class receptor binding means the ability of a molecule to stick to the Neu/ErbB-2/HER2 receptor. The QuickGO definition states that this molecular function is binding to a protein-tyrosine kinase receptor Neu/ErbB-2/HER2. It is a molecular_function term, not a biological process or cellular component, and its synonyms include ErbB-2 class receptor ligand, HER2 receptor binding, HER2 receptor ligand, Neu receptor binding and Neu receptor ligand. Experimentally, this function is demonstrated by binders such as Affibody molecules Z(HER2:342) and Z(HER2:2395) that selectively associate with the HER2 receptor.
Why Is ErbB-2 class receptor binding Important in Cell Biology?
GO:0005176 ErbB-2 class receptor binding is important because it defines the molecular recognition event at the HER2/Neu/ErbB-2 receptor, a receptor tyrosine kinase with major roles in oncology and molecular imaging. Experimental binders annotated to this term, such as Z(HER2:342) and Z(HER2:2395), have been developed as radiolabeled probes for receptor-specific imaging, enabling non-invasive assessment of HER2 expression. Understanding this binding function supports target validation, tracer development and mechanistic studies of receptor-ligand interactions.
• Defines the molecular recognition event for the HER2/Neu/ErbB-2 receptor tyrosine kinase.
• Provides a functional annotation for engineered Affibody binders such as Z(HER2:342).
• Enables HER2-targeted molecular imaging with 99mTc- and 111In-labeled probes.
• Supports development of fluorescent binders for optical imaging of HER2.
• Helps validate receptor accessibility and expression in tumor models.
• Connects binding chemistry to translational applications in cancer diagnostics.
• Facilitates comparison of different binder scaffolds and labeling strategies.
• Underpins mechanistic studies of receptor-ligand association at the HER2 ectodomain.
Molecular Mechanism of ErbB-2 class receptor binding
Receptor recognition by HER2-specific binders
In simple terms: A binder molecule finds and attaches to the HER2 receptor on the cell surface.
The core event of GO:0005176 is the physical association of a binder with the Neu/ErbB-2/HER2 receptor. Affibody molecules such as Z(HER2:342) and Z(HER2:2395) are engineered to recognize the HER2 ectodomain and are used experimentally to demonstrate this binding function. These binders provide a direct way to study receptor recognition and are compatible with radiolabeling and fluorescent conjugation.
Radiolabeled binding probes
In simple terms: Scientists attach a radioactive tag to the binder so they can see where it sticks in the body.
GO:0005176 is frequently studied using radiolabeled Affibody constructs. For example, 99mTc-Affibody Z(HER2:2395)-Cys and 99mTc-Mercaptoacetyl-Glu-Glu-Glu-Affibody Z(HER2:342) have been generated and characterized as HER2-binding probes. Similarly, 111In-Benzyl-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid-Z(HER2:342) and 111In-CHX-A''-diethylenepentaacetic acid-Affibody Z(HER2:2395)-Cys have been used to evaluate receptor binding with SPECT-compatible isotopes. These reagents operationalize the GO:0005176 function in imaging experiments.
Fluorescent and optical binding formats
In simple terms: A glowing tag on the binder lets researchers watch binding under a microscope or imaging system.
Beyond radioactivity, fluorescent derivatives support optical detection of ErbB-2 class receptor binding. Cy5.5-8-Amino-octanoic acid-Ser-Cys-Pro-Pro-Trp-Gln-Glu-Trp-His-Asn-Phe-Met-Pro-Phe-NH(2) is a fluorescent construct used in this context. Such reagents allow binding to be monitored with fluorescence-based methods and complement radiolabeled approaches for studying GO:0005176.
Binding specificity and construct design
In simple terms: The binder is designed so it prefers HER2 over other receptors.
The Affibody scaffolds Z(HER2:342) and Z(HER2:2395) are engineered variants selected for HER2 recognition, and their derivatives are used to probe GO:0005176. The choice of chelator, linker and labeling chemistry can influence binding behavior, which is why multiple formats such as Cys-Gly-Gly-Affibody Z(HER2:342) and Ac-Cys-Z(EGFR:1907) controls have been described. These design considerations are central to interpreting ErbB-2 class receptor binding assays.
Regulation and context dependence
In simple terms: How much binder sticks to HER2 depends on how much receptor is available and how it is presented.
The apparent level of GO:0005176 activity in an experiment depends on receptor expression, accessibility and the specific binding format used. Studies with 99mTc- and 111In-labeled Affibody molecules demonstrate that tracer uptake reflects available HER2 receptor. Therefore, binding measurements must be interpreted in the context of receptor abundance and probe properties.
Key Genes Involved in GO:0005176 ErbB-2 class receptor binding
The following genes and proteins are directly relevant to GO:0005176 ErbB-2 class receptor binding, either as the receptor itself or as validated experimental binders and labeling partners.
| Gene | Major Role | Research Relevance |
|---|---|---|
| ERBB2 (HER2/Neu) | Receptor tyrosine kinase targeted by GO:0005176 binders | Central receptor for binding assays and imaging |
| Z(HER2:342) Affibody | Engineered binder of HER2 | Used in 99mTc and 111In imaging probes |
| Z(HER2:2395) Affibody | Engineered binder of HER2 | Used in 99mTc and 111In imaging probes |
| EGFR | Related receptor tyrosine kinase | Used as control in binder specificity studies |
| Cys-Gly-Gly-Affibody Z(HER2:342) | Labeled HER2 binder | 99mTc-conjugated probe for receptor binding |
| Mercaptoacetyl-Glu-Glu-Glu-Affibody Z(HER2:342) | Labeled HER2 binder | 99mTc-conjugated probe for receptor binding |
| Benzyl-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid-Z(HER2:342) | Chelator-conjugated HER2 binder | 111In-labeled probe for SPECT imaging |
| CHX-A''-diethylenepentaacetic acid-Affibody Z(HER2:2395)-Cys | Chelator-conjugated HER2 binder | 111In-labeled probe for SPECT imaging |
| Cy5.5-8-Amino-octanoic acid-Ser-Cys-Pro-Pro-Trp-Gln-Glu-Trp-His-Asn-Phe-Met-Pro-Phe-NH(2) | Fluorescent HER2 binder | Optical imaging of receptor binding |
| Ac-Cys-Z(EGFR:1907) | Control binder for EGFR | Specificity comparison in binding studies |
| N-[2-(4-[18F]Fluorobenzamido)ethyl]maleimide-Cys-Z(EGFR:1907) | Control binder for EGFR | Specificity comparison in binding studies |
| HER2 ectodomain | Extracellular region recognized by binders | Direct binding interface for GO:0005176 |
| Affibody scaffold | Small engineered protein framework | Platform for generating HER2 binders |
| Chelator moieties | Metal-binding groups for radiolabeling | Enable 99mTc and 111In detection |
| Fluorescent dyes | Optical tags | Enable fluorescence-based binding detection |
| Cys residues | Site-specific conjugation handles | Used for labeling Affibody constructs |
| Peptide linkers | Spacers between binder and label | Modulate binding and pharmacokinetics |
How Is ErbB-2 class receptor binding Regulated?
The functional readout of GO:0005176 ErbB-2 class receptor binding is regulated by the availability and accessibility of the HER2/Neu/ErbB-2 receptor, as well as by the properties of the binding construct. Studies using 99mTc- and 111In-labeled Affibody molecules show that tracer accumulation depends on receptor expression and targeting format. In addition, the choice of chelator, linker and conjugation site can affect binding performance, as illustrated by comparisons among different Affibody derivatives. Fluorescent constructs such as Cy5.5-labeled peptides provide complementary regulation readouts through optical detection.
ErbB-2 class receptor binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| ERBB2 (HER2/Neu) | HER2-positive cancer | HER2-expressing tumor xenografts for Affibody imaging |
| ERBB2 (HER2/Neu) | Receptor overexpression biology | Cell lines with defined HER2 levels for binding assays |
| ERBB2 (HER2/Neu) | Molecular imaging of receptor status | SPECT/PET imaging with radiolabeled Affibody probes |
| EGFR | Related receptor tyrosine kinase biology | Control binding studies with EGFR-specific Affibody constructs |
| ERBB2 (HER2/Neu) | Optical imaging of receptor expression | Fluorescent binder imaging in HER2-positive models |
HER2-positive cancers
GO:0005176 ErbB-2 class receptor binding is directly linked to HER2-positive cancers because the HER2/Neu/ErbB-2 receptor is a major oncogenic driver and a target for imaging and therapy. Radiolabeled Affibody molecules such as 99mTc-Affibody Z(HER2:2395)-Cys and 111In-labeled constructs have been developed to detect HER2 expression in tumor models. These binding probes support non-invasive assessment of receptor status and are relevant to cancer diagnostics.
Molecular imaging of receptor expression
The binding function defined by GO:0005176 is central to molecular imaging strategies that visualize HER2 receptor levels. 99mTc- and 111In-labeled Affibody constructs enable SPECT imaging of HER2, while fluorescent derivatives support optical detection. These approaches help researchers study receptor distribution and target engagement in disease models.
Target validation for therapeutic development
Because GO:0005176 describes binding to HER2, it provides a functional basis for target validation in therapeutic development. Engineered binders such as Z(HER2:342) and Z(HER2:2395) demonstrate that specific receptor recognition can be achieved and measured. Such reagents are useful for confirming target accessibility and for guiding the design of HER2-directed agents.
From ErbB-2 class receptor binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does a candidate binder recognize HER2? | In vitro binding assay with purified HER2 ectodomain or HER2-positive cells |
| Where does the binder accumulate in vivo? | Radiolabeled Affibody imaging in HER2-expressing xenografts |
| Can binding be detected optically? | Fluorescent Cy5.5-labeled binder in cell or tissue imaging |
| How specific is the binder for HER2 versus EGFR? | Comparative binding with HER2 and EGFR Affibody constructs |
| Does labeling chemistry affect binding? | Side-by-side testing of different chelator-Affibody formats |
| Can receptor levels be quantified? | Quantitative SPECT/PET with 99mTc- or 111In-labeled probes |
How to Study the ErbB-2 class receptor binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| 99mTc-Affibody binding assay | HER2-specific binding | In vitro and in vivo receptor targeting |
| 111In-Affibody SPECT | Receptor distribution | HER2 imaging in tumor models |
| Fluorescence imaging | Optical detection of binding | Cellular and tissue localization of binders |
| Competition binding | Specificity of receptor association | Comparing HER2 versus EGFR binders |
| Biodistribution | Tissue uptake of radiolabeled binder | In vivo targeting evaluation |
| Chelator conjugation | Labeling efficiency and stability | Probe development for SPECT |
| Peptide design | Linker and label effects on binding | Optimization of Affibody constructs |
| Control receptor binding | Cross-reactivity assessment | Specificity validation with EGFR constructs |
Radiolabeled binding assays
Radiolabeled Affibody molecules are used to measure GO:0005176 ErbB-2 class receptor binding. 99mTc-Affibody Z(HER2:2395)-Cys and 99mTc-Mercaptoacetyl-Glu-Glu-Glu-Affibody Z(HER2:342) have been characterized as HER2-binding probes. 111In-labeled constructs such as 111In-Benzyl-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid-Z(HER2:342) and 111In-CHX-A''-diethylenepentaacetic acid-Affibody Z(HER2:2395)-Cys further demonstrate the use of SPECT-compatible isotopes.
Fluorescence-based detection
Fluorescent derivatives enable optical detection of ErbB-2 class receptor binding. Cy5.5-8-Amino-octanoic acid-Ser-Cys-Pro-Pro-Trp-Gln-Glu-Trp-His-Asn-Phe-Met-Pro-Phe-NH(2) is an example of a fluorescent construct used for this purpose. Such methods complement radiolabeled approaches and allow binding to be visualized at the cellular level.
Specificity controls with related receptors
To confirm that a binder satisfies GO:0005176, specificity controls using related receptors such as EGFR are valuable. Ac-Cys-Z(EGFR:1907) and N-[2-(4-[18F]Fluorobenzamido)ethyl]maleimide-Cys-Z(EGFR:1907) are EGFR-targeted constructs that can be used as comparators. These controls help distinguish HER2-specific binding from cross-reactivity.
Imaging and biodistribution studies
In vivo imaging and biodistribution studies operationalize GO:0005176 by tracking radiolabeled binders in HER2-expressing models. 99mTc- and 111In-labeled Affibody constructs have been used to evaluate receptor targeting and probe distribution. These methods connect molecular binding to whole-body receptor imaging.
How CRISPR Can Be Used to Study GO:0005176 ErbB-2 class receptor binding
Knockout
CRISPR knockout of ERBB2 can eliminate HER2 expression and provide a negative background for GO:0005176 binding studies. Such models help confirm that observed binding is receptor-dependent and support specificity claims for Affibody probes.
Point Mutation
Point mutations in ERBB2 can be introduced to test how specific receptor residues contribute to ErbB-2 class receptor binding. These models allow structure-function analysis of the HER2 ectodomain and help map the binding interface recognized by Affibody molecules.
Knock-in
Knock-in of tagged or reporter-linked ERBB2 enables direct visualization and quantification of receptor availability for GO:0005176 binders. Tagged receptor models can be combined with radiolabeled or fluorescent probes to correlate receptor levels with binding signals.
Overexpression
Overexpression of ERBB2 creates high-receptor-density cells that are useful for detecting and characterizing ErbB-2 class receptor binding. HER2-overexpressing models are commonly used to evaluate Affibody-based imaging probes and to benchmark binding performance.
How EDITGENE Supports ErbB-2 class receptor binding Research
Researchers studying ErbB-2 class receptor binding-related genes often need to determine whether a candidate gene is causally involved in receptor recognition, whether a specific mutation alters binding, or whether receptor levels can be reliably modeled in cells. EDITGENE provides CRISPR-based cell model services that support these questions with validated knockout, point-mutation, knock-in and overexpression platforms.
Contact EDITGENE today to design your custom CRISPR model for ErbB-2 class receptor binding research.
Frequently Asked Questions About ErbB-2 class receptor binding
What is GO:0005176 ErbB-2 class receptor binding?
GO:0005176 is a molecular_function term defined as binding to a protein-tyrosine kinase receptor Neu/ErbB-2/HER2.
What genes are involved in ErbB-2 class receptor binding?
The central gene is ERBB2 (HER2/Neu), and experimental binders include Affibody molecules such as Z(HER2:342) and Z(HER2:2395).
What are the synonyms of GO:0005176?
Synonyms include ErbB-2 class receptor ligand, HER2 receptor binding, HER2 receptor ligand, Neu receptor binding and Neu receptor ligand.
Which experimental binders are used to study HER2 receptor binding?
Affibody molecules Z(HER2:342) and Z(HER2:2395) and their radiolabeled or fluorescent derivatives are commonly used.
How is ErbB-2 class receptor binding measured?
It is measured with radiolabeled binding assays, SPECT imaging using 99mTc- or 111In-labeled probes, and fluorescence-based detection.
Why is HER2 receptor binding important in cancer?
HER2 is a major oncogenic receptor, and binding probes enable non-invasive imaging and target validation in HER2-positive cancers.
What is the difference between HER2 and EGFR binding in these studies?
HER2-specific Affibody constructs bind HER2, while EGFR-targeted constructs such as Z(EGFR:1907) are used as specificity controls.
Can CRISPR be used to study ErbB-2 class receptor binding?
Yes, CRISPR knockout, point mutation, knock-in and overexpression models can be used to manipulate ERBB2 and test binding phenotypes.
What imaging isotopes are used for HER2 Affibody probes?
99mTc and 111In are used for SPECT-compatible HER2 Affibody probes.
What is the QuickGO definition of GO:0005176?
The QuickGO definition is binding to a protein-tyrosine kinase receptor Neu/ErbB-2/HER2.
Conclusion
GO:0005176 ErbB-2 class receptor binding defines the molecular recognition of the HER2/Neu/ErbB-2 receptor by binding molecules. Validated experimental binders such as Z(HER2:342) and Z(HER2:2395) Affibody constructs, including 99mTc- and 111In-labeled derivatives, provide practical tools for studying this function in vitro and in vivo. These reagents support HER2-targeted imaging, specificity testing and receptor biology research. Because HER2 is a clinically important receptor, precise models of ErbB-2 class receptor binding are valuable for both basic and translational studies. CRISPR-based knockout, point-mutation, knock-in and overexpression models can complement binding assays and imaging probes to clarify how receptor availability and structure influence binding.
References
- 1. Leung K. 2004. Cy5.5-Ac-Cys-Z(EGFR:1907).. PMID: 22973578
- 2. Leung K. 2004. N-[2-(4-[(18)F]Fluorobenzamido)ethyl]maleimide-Cys-Z(EGFR:1907).. PMID: 23136679
- 3. Leung K. 2004. (99m)Tc-Affibody Z(HER2:2395)-Cys.. PMID: 20641788
- 4. Leung K. 2004. (99m)Tc-Mercaptoacetyl-Glu-Glu-Glu-Affibody Z(HER2:342).. PMID: 20641930
- 5. Leung K. 2004. (99m)Tc-Cys-Gly-Gly-Affibody Z(HER2:342).. PMID: 20641196
- 6. Leung K. 2004. (111)In-Benzyl-tetraazacyclododecane-N,N’,N’’,N’’’-tetraacetic acid-Z(HER2:342).. PMID: 20641264
- 7. Leung K. 2004. Cy5.5-8-Amino-octanoic acid-Ser-Cys-Pro-Pro-Trp-Gln-Glu-Trp-His-Asn-Phe-Met-Pro-Phe-NH(2).. PMID: 23166962
- 8. Leung K. 2004. (111)In-CHX-A”-diethylenepentaacetic acid-Affibody Z(HER2:2395)-Cys.. PMID: 20641462
