GO:0032190 acrosin binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0032190 acrosin binding is a molecular function defined as binding to acrosin, a sperm acrosomal protein with protease and carbohydrate-binding activities.
• Acrosin binding is mediated by proteins such as ACRBP and CRISP2, which interact with acrosin in the acrosome of spermatozoa [1,5].
• Acrosin itself binds to zona pellucida glycoproteins and fucose, and its limited proteolysis of the zona pellucida affects sperm binding and mechanical resilience [3,6,8].
• Disruption of acrosin binding may contribute to infertility, as antisperm antibodies against acrosin are found in some patients with unexplained infertility.
• ACRBP, a major acrosin-binding protein, is also expressed in cancers and its alternative splicing is being explored for therapy.
• Research on acrosin binding uses knockout, knock-in, and overexpression models, combined with proteomics, imaging, and functional assays [1,3,5].
Description
Acrosin binding (GO:0032190) is a molecular function that describes the selective interaction of a protein with acrosin, a serine protease stored in the acrosome of spermatozoa [1,8]. Acrosin is a multifunctional enzyme that possesses both protease and carbohydrate-binding activities, enabling it to recognize and cleave zona pellucida glycoproteins during fertilization [6,8]. The binding of acrosin to partner proteins is critical for acrosome function, sperm-zona pellucida interaction, and successful fertilization [1,3,7]. This GO term captures the physical association between acrosin and its binding partners, which include the acrosin-binding protein (ACRBP) and cysteine-rich secretory protein 2 (CRISP2) [1,5]. Understanding acrosin binding is essential for reproductive biology, as defects in this process are linked to male infertility and antisperm antibody-mediated infertility. Moreover, acrosin-binding proteins such as ACRBP have been implicated in cancer biology, where alternative splicing of ACRBP RNA transcripts may offer therapeutic opportunities. Researchers studying acrosin binding aim to elucidate the molecular mechanisms of fertilization, develop diagnostic markers for infertility, and explore targeted interventions [3,5,7].
acrosin binding At A Glance
| GO ID | GO:0032190 |
|---|---|
| GO term | acrosin binding |
| Ontology | molecular_function |
| Synonym | acrosin heavy chain binding, acrosin light chain binding |
| Major function | Binding to acrosin, a sperm acrosomal protease with carbohydrate-binding activity |
| Definition source | QuickGO |
| Related cellular component | Acrosome |
| Related biological process | Fertilization, sperm-zona pellucida interaction |
| Example binding proteins | ACRBP, CRISP2 |
What Is GO:0032190?
According to the Gene Ontology, acrosin binding (GO:0032190) is the binding to acrosin, a protein found in the acrosomes of sperm that possesses protease and carbohydrate binding activities. This molecular function encompasses the physical interaction between acrosin and other proteins or molecules, and it includes the synonyms acrosin heavy chain binding and acrosin light chain binding. The term is used to annotate gene products that directly bind to acrosin, thereby modulating its activity, localization, or function within the acrosome.
Why Is acrosin binding Important in Cell Biology?
Acrosin binding is important because it regulates the activity and availability of acrosin, a key enzyme for sperm penetration through the zona pellucida during fertilization [3,6]. Disruption of acrosin binding can impair sperm function and contribute to infertility, as evidenced by antisperm antibodies targeting acrosin in patients with unexplained infertility. Additionally, acrosin-binding proteins such as ACRBP are not only relevant to reproduction but also have emerging roles in cancer, where their expression and splicing patterns are being investigated as therapeutic targets. Thus, studying acrosin binding provides insights into both reproductive biology and disease mechanisms.
• Regulates acrosin activity and localization in the acrosome, affecting sperm function.
• Essential for sperm-zona pellucida binding and penetration during fertilization [3,6].
• Antisperm antibodies against acrosin are associated with unexplained infertility.
• ACRBP, a major acrosin-binding protein, is a potential cancer biomarker and therapeutic target.
• CRISP2 interacts with acrosin and ACRBP, influencing sperm capacitation and acrosome reaction.
• Acrosin binding is a model for studying protein-protein interactions in reproductive biology.
• Defects in acrosin binding may lead to male infertility and poor fertilization outcomes.
• Acrosin binding is relevant for contraceptive development and reproductive medicine.
• Alternative splicing of ACRBP RNA transcripts may contribute to cancer progression.
• Studying acrosin binding can reveal mechanisms of protease regulation in the acrosome.
Molecular Mechanism of acrosin binding
Acrosin structure and carbohydrate binding
In simple terms: Acrosin is a sperm enzyme that can grab onto sugar molecules and proteins.
Acrosin is a serine protease found in the acrosome of spermatozoa, and it exhibits both protease and carbohydrate-binding activities. It binds to zona pellucida glycoproteins, particularly ZPA, ZPB, and ZPC, through its carbohydrate-binding sites. This binding is essential for the initial recognition and penetration of the egg coat during fertilization [6,7].
Interaction with ACRBP
In simple terms: ACRBP is a protein that sticks to acrosin and helps control its function.
Acrosin-binding protein (ACRBP) is a major binding partner of acrosin in the acrosome [1,5]. In boar spermatozoa, ACRBP forms complexes with acrosin and CRISP2, suggesting a role in acrosome stabilization and sperm function. ACRBP is also expressed in the testes of stallions, where it may regulate acrosin activity.
Interaction with CRISP2
In simple terms: CRISP2 is another protein that binds to acrosin and ACRBP, forming a network.
CRISP2 (cysteine-rich secretory protein 2) interacts with both acrosin and ACRBP in boar spermatozoa. This ternary complex may modulate acrosin's protease activity and its interaction with the zona pellucida. CRISP2 is known to be involved in sperm capacitation and the acrosome reaction, and its binding to acrosin highlights a regulatory mechanism.
Limited proteolysis of zona pellucida
In simple terms: Acrosin cuts the egg coat proteins, which changes how sperm bind to the egg.
Acrosin undergoes limited proteolysis of the mouse zona pellucida, which affects sperm-binding and the mechanical resilience of the zona pellucida. This proteolytic activity is modulated by acrosin binding proteins, which may control the extent of zona pellucida digestion. The balance between acrosin activity and its inhibitors is crucial for successful fertilization.
Regulation by antisperm antibodies
In simple terms: Antibodies against acrosin can block its function and cause infertility.
Antisperm antibodies that bind to human acrosin have been detected in patients with unexplained infertility. These antibodies may interfere with acrosin's binding to zona pellucida or its proteolytic activity, thereby impairing fertilization. This highlights the clinical importance of acrosin binding in reproductive immunology.
Key Genes Involved in GO:0032190 acrosin binding
The following genes and proteins are directly involved in acrosin binding or are major binding partners of acrosin.
| Gene | Major Role | Research Relevance |
|---|---|---|
| ACR | Encodes acrosin, a serine protease with carbohydrate-binding activity | Central to acrosin binding; target for knockout and point mutation studies [6,8] |
| ACRBP | Encodes acrosin-binding protein, a major partner of acrosin | Involved in acrosome function and cancer; studied in KO and overexpression models [1,2,5] |
| CRISP2 | Encodes cysteine-rich secretory protein 2, interacts with acrosin and ACRBP | Modulates sperm function; used in interaction studies |
| ZP2 | Encodes zona pellucida glycoprotein 2, a binding partner of acrosin | Studied for sperm-egg binding; relevant to acrosin binding assays |
| ZP3 | Encodes zona pellucida glycoprotein 3, binds acrosin | Key for acrosin binding and fertilization research |
| ZP4 | Encodes zona pellucida glycoprotein 4, binds acrosin | Involved in acrosin binding studies |
| SPAM1 | Encodes PH-20, a sperm adhesion molecule | May cooperate with acrosin in zona binding |
| ACE | Angiotensin-converting enzyme, involved in sperm function | Potential modifier of acrosin binding |
| PRSS21 | Testisin, a serine protease in sperm | May interact with acrosin pathways |
| TMPRSS12 | Transmembrane protease, serine 12 | Potential role in sperm function |
| IZUMO1 | Sperm-egg fusion protein | Downstream of acrosin binding |
| CATSPER1 | Sperm cation channel | Affects sperm motility and acrosin release |
| PCSK4 | Proprotein convertase subtilisin/kexin type 4 | Activates acrosin precursors |
| SERPINA5 | Plasma serine protease inhibitor | Regulates acrosin activity |
| CST3 | Cystatin C, protease inhibitor | May modulate acrosin |
| A2M | Alpha-2-macroglobulin, protease inhibitor | Potential regulator of acrosin |
| HSPA8 | Heat shock protein family A member 8 | Chaperone for acrosin folding |
| BAG5 | BAG cochaperone 5 | Interacts with ACRBP |
How Is acrosin binding Regulated?
Acrosin binding is regulated at multiple levels. The interaction between acrosin and ACRBP is modulated by CRISP2, which forms a complex in spermatozoa. Limited proteolysis of the zona pellucida by acrosin is controlled by protease inhibitors such as SERPINA5 and CST3. Additionally, antisperm antibodies can block acrosin binding, leading to infertility. The expression of ACRBP is regulated by alternative splicing, which may affect its binding properties.
acrosin binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| ACR | Male infertility due to impaired acrosin function | Acr knockout mouse |
| ACRBP | Cancer progression and infertility | ACRBP knockout and overexpression cell lines |
| CRISP2 | Sperm dysfunction and infertility | Crisp2 knockout mouse |
| ZP2 | Fertilization failure | Zp2 mutant mouse |
| SERPINA5 | Infertility and thrombosis | Serpina5 knockout mouse |
Male infertility and antisperm antibodies
Acrosin binding is critical for sperm-zona pellucida interaction, and disruption of this process can lead to male infertility [4,7]. Antisperm antibodies against acrosin have been found in patients with unexplained infertility, suggesting an autoimmune component. Sperm-zona pellucida binding correlates with the presence of proacrosin and acrosin in sperm heads, but not with proteolytic activity alone, indicating that binding is essential.
Cancer and ACRBP
ACRBP, a major acrosin-binding protein, is expressed in various cancers, and alternative splicing of its RNA transcript may contribute to cancer progression. Targeting ACRBP or its interactions with acrosin could offer novel therapeutic strategies. Research into ACRBP splicing is ongoing for innovative cancer therapy.
Fertilization failure and zona pellucida defects
Acrosin binding to zona pellucida glycoproteins is essential for fertilization, and defects in this interaction can cause fertilization failure [6,8]. Limited proteolysis of the zona pellucida by acrosin affects sperm binding and mechanical resilience, and abnormalities in this process may lead to infertility.
From acrosin binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does ACRBP binding to acrosin affect acrosome reaction? | ACRBP knockout mouse sperm |
| How does CRISP2 modulate acrosin activity? | CRISP2 point mutation knock-in mouse |
| What is the role of acrosin carbohydrate binding in fertilization? | ACR point mutations in carbohydrate-binding domain |
| Can ACRBP splicing variants promote cancer? | ACRBP overexpression and knockdown in cancer cell lines |
| Does acrosin binding to ZP2 require specific residues? | ZP2 knock-in mutations in mouse |
| How do antisperm antibodies affect acrosin binding? | Passive immunization mouse model |
How to Study the acrosin binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Co-immunoprecipitation | Protein-protein interactions with acrosin | Identifying ACRBP and CRISP2 |
| Sperm-zona pellucida binding assay | Binding capacity of sperm to zona pellucida | Assessing acrosin function |
| In vitro fertilization | Fertilization rate | Testing acrosin binding defects |
| Immunofluorescence | Localization of acrosin and partners | Acrosome imaging |
| CRISPR knockout | Gene function in acrosin binding | ACRBP and CRISP2 studies |
| Mass spectrometry | Identification of binding partners | Interactome discovery |
| Limited proteolysis assay | Zona pellucida digestion | Acrosin activity measurement |
| Antibody binding assay | Antisperm antibody presence | Infertility diagnostics |
Proteomic and interactomic approaches
Co-immunoprecipitation coupled with mass spectrometry can identify acrosin-binding partners in sperm lysates. This method has been used to discover ACRBP and CRISP2 as acrosin interactors in boar spermatozoa. Affinity purification using recombinant acrosin as bait is also effective.
Functional fertilization assays
Sperm-zona pellucida binding assays and in vitro fertilization (IVF) experiments measure the functional impact of acrosin binding [3,6]. These assays can be combined with acrosin inhibitors or antibodies to assess binding specificity. Limited proteolysis of zona pellucida can be monitored by gel electrophoresis.
Imaging and localization studies
Immunocytochemistry and immunofluorescence localize acrosin and its binding partners in sperm heads and acrosomes. Live-cell imaging with fluorescently tagged acrosin can track binding dynamics during the acrosome reaction. Electron microscopy reveals ultrastructural details of acrosin complexes.
Genetic and CRISPR screens
CRISPR knockout screens in sperm cell lines or mouse models can identify genes required for acrosin binding. Point mutations in acrosin or its partners can be introduced to test specific residues. Overexpression of ACRBP in cancer cells helps study its oncogenic roles.
How CRISPR Can Be Used to Study GO:0032190 acrosin binding
Knockout
CRISPR knockout of ACRBP or CRISP2 in mouse models or sperm cell lines can reveal their essential roles in acrosin binding and fertilization [1,2]. Knockout of ACR in mice leads to impaired zona pellucida penetration. These models help determine causality between acrosin binding and fertility.
Point Mutation
Introducing point mutations in the acrosin carbohydrate-binding domain or in ACRBP interaction interfaces can dissect specific binding residues. For example, mutating ZP2 residues that interact with acrosin can test binding specificity. Such models are valuable for understanding molecular recognition.
Knock-in
Knock-in of tagged acrosin (e.g., GFP) allows real-time tracking of acrosin binding in live sperm. Knock-in of disease-associated ACRBP splicing variants can model cancer-related splicing changes. These models facilitate dynamic studies of acrosin binding.
Overexpression
Overexpression of ACRBP in cancer cell lines can mimic its oncogenic role and test drug sensitivity. Overexpression of CRISP2 in sperm cells can enhance acrosin binding and modulate acrosome reaction. These models are useful for gain-of-function studies.
How EDITGENE Supports acrosin binding Research
Researchers studying acrosin binding-related genes often need to determine whether a candidate gene is causally involved in acrosin binding, sperm function, or disease. EDITGENE provides comprehensive CRISPR gene editing services to create precisely tailored cell and animal models for such investigations.
Contact EDITGENE today to design your custom CRISPR model for acrosin binding research.
Frequently Asked Questions About acrosin binding
What is acrosin binding?
Acrosin binding is a molecular function (GO:0032190) where a protein binds to acrosin, a sperm acrosomal enzyme with protease and carbohydrate-binding activities [1,8].
What genes are involved in acrosin binding?
Key genes include ACR (acrosin), ACRBP (acrosin-binding protein), and CRISP2, which form complexes in spermatozoa [1,5].
How does acrosin binding affect fertility?
Acrosin binding is essential for sperm-zona pellucida interaction and penetration; disruption can lead to infertility [3,7].
What is the role of ACRBP in acrosin binding?
ACRBP is a major acrosin-binding protein that stabilizes acrosin and may regulate its activity in the acrosome [1,5].
Can acrosin binding be studied with CRISPR?
Yes, CRISPR knockout, knock-in, and point mutation models are used to study acrosin binding genes in sperm and cancer cells [2,6].
Is acrosin binding related to cancer?
ACRBP, an acrosin-binding protein, is expressed in cancers, and its alternative splicing is being explored for therapy.
What diseases are associated with acrosin binding defects?
Male infertility, unexplained infertility with antisperm antibodies, and fertilization failure are linked to acrosin binding defects [4,7].
How is acrosin binding measured experimentally?
Co-immunoprecipitation, sperm-zona pellucida binding assays, and immunofluorescence are common methods [1,3,7].
What is the GO term for acrosin binding?
The Gene Ontology term is GO:0032190, defined as binding to acrosin, a sperm acrosomal protein [QuickGO].
Which proteins interact with acrosin?
ACRBP and CRISP2 are well-characterized acrosin-interacting proteins in spermatozoa.
Conclusion
Acrosin binding (GO:0032190) is a specialized molecular function critical for sperm function and fertilization. It involves interactions between acrosin and proteins such as ACRBP and CRISP2, and it is regulated by proteolysis and antibodies. Dysregulation of acrosin binding is linked to infertility and cancer, making it a valuable target for reproductive and oncological research. Advances in CRISPR gene editing and proteomics continue to unravel the molecular details of acrosin binding, offering new avenues for diagnostics and therapeutics.
References
- 1. Zhang M et al.. 2023. Characterization of acrosin and acrosin binding protein as novel CRISP2 interacting proteins in boar spermatozoa.. Andrology 11(7):1460-1471 PMID: 36815564
- 2. Editorial Office of Asian Biomedicine. 2020. Alternative splicing of acrosin binding protein RNA transcript and its potential contributions to innovative cancer therapy.. Asian Biomed (Res Rev News) 14(6):215-216 PMID: 37551307
- 3. Kuske M et al.. 2021. Limited proteolysis by acrosin affects sperm-binding and mechanical resilience of the mouse zona pellucida.. Mol Hum Reprod 27(4) PMID: 33779727
- 4. Howe SE et al.. 1991. Antisperm antibody binding to human acrosin: a study of patients with unexplained infertility.. Fertil Steril 55(6):1176-82 PMID: 2037111
- 5. Kim JT et al.. 2015. Acrosin-binding protein (ACRBP) in the testes of stallions.. Anim Reprod Sci 163:179-86 PMID: 26597026
- 6. Furlong LI et al.. 2005. Binding of recombinant human proacrosin/acrosin to zona pellucida (ZP) glycoproteins. I. Studies with recombinant human ZPA, ZPB, and ZPC.. Fertil Steril 83(6):1780-90 PMID: 15950651
- 7. Francavilla S et al.. 1994. Sperm-zona pellucida binding of human sperm is correlated with the immunocytochemical presence of proacrosin and acrosin in the sperm heads but not with the proteolytic activity of acrosin.. Fertil Steril 62(6):1226-33 PMID: 7957989
- 8. Töpfer-Petersen E et al.. 1987. Acrosin shows zona and fucose binding, novel properties for a serine proteinase.. FEBS Lett 226(1):38-42 PMID: 3480243
