GO:0017002 activin receptor activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0017002 (activin receptor activity) describes the molecular function of combining with activin and transmitting the signal across the membrane to initiate a change in cell activity.
• Activin receptors are serine/threonine kinase receptors of the TGF-beta superfamily, typically forming type I (ALK4/ALK7) and type II (ACVR2A/ACVR2B) complexes.
• Activin signaling is critical in reproduction, muscle homeostasis, fibrosis, and cancer, making it a therapeutic target.
• Small-molecule inhibitors such as SB-431542 block ALK4/ALK5/ALK7 and are widely used to study activin receptor function.
• Endogenous inhibitors like DLK1 and therapeutic agents like dalantercept modulate activin receptor activity in disease models.
• CRISPR-based knockout, knock-in, and overexpression models enable precise dissection of activin receptor signaling in vitro and in vivo.
Description
Activin receptor activity (GO:0017002) is a molecular function that mediates cellular responses to activin, a member of the transforming growth factor beta (TGF-beta) superfamily. This activity is essential for transmitting signals from the cell surface to the nucleus, thereby regulating diverse biological processes including cell proliferation, differentiation, and apoptosis. Dysregulation of activin receptor signaling has been implicated in a wide range of pathologies, from cancer to metabolic disorders. Understanding the precise molecular mechanisms of activin receptor activity is therefore crucial for both basic research and therapeutic development. Recent studies have identified specific type I and type II receptors, such as ALK4, ALK7, ACVR2A, and ACVR2B, that mediate activin signaling. Moreover, endogenous modulators like DLK1 and pharmacological inhibitors like SB-431542 provide tools to probe this pathway. This article synthesizes current knowledge on the genes, mechanisms, and research methods associated with GO:0017002, offering a comprehensive resource for researchers.
activin receptor activity At A Glance
| GO ID | GO:0017002 |
|---|---|
| GO term | activin receptor activity |
| Ontology | molecular_function |
| Synonym | activin-activated receptor activity |
| Major function | Binding activin and transmitting signals across the membrane to initiate cellular responses |
| Receptor types | Type I (ALK4, ALK7) and type II (ACVR2A, ACVR2B) serine/threonine kinases |
| Signaling pathway | SMAD2/3-dependent canonical pathway and non-canonical branches |
| Endogenous inhibitors | DLK1, follistatin |
| Pharmacological inhibitors | SB-431542, dalantercept |
What Is GO:0017002?
According to the Gene Ontology, activin receptor activity (GO:0017002) is defined as the molecular function of combining with activin and transmitting the signal from one side of the membrane to the other to initiate a change in cell activity. Activin is one of two gonadal glycoproteins related to transforming growth factor beta. This activity is typically mediated by receptor serine/threonine kinases that form heteromeric complexes and activate intracellular signaling cascades, such as the SMAD pathway.
Why Is activin receptor activity Important in Cell Biology?
Activin receptor activity is a central node in TGF-beta superfamily signaling, controlling fundamental processes such as embryonic development, tissue homeostasis, and immune regulation. Its dysregulation contributes to cancer progression, muscle wasting, fibrosis, and reproductive disorders. Therefore, targeting activin receptors holds therapeutic promise, as evidenced by inhibitors like dalantercept and SB-431542. Moreover, understanding this activity at the molecular level informs the design of CRISPR-based models to study gene function and disease mechanisms.
• Regulates cell proliferation, differentiation, and apoptosis in multiple tissues.
• Critical for reproductive biology, including ovarian and testicular function.
• Involved in muscle homeostasis; blockade increases muscle mass but may affect glycemic control.
• Implicated in cancer, where activin signaling can promote or suppress tumor growth depending on context.
• Plays a role in fibrosis and pulmonary hypertension through ALK2 regulation.
• Therapeutic target for muscle loss and obesity; GDF8/activin A blockade enhances fat loss.
• Endogenous inhibitor DLK1 provides a mechanism for fine-tuning activin receptor activity.
• Small-molecule inhibitors like SB-431542 are valuable research tools.
• Activin E signals specifically through ALK7, highlighting ligand-receptor specificity.
• CRISPR screens can identify novel regulators of activin receptor signaling.
Molecular Mechanism of activin receptor activity
Ligand Binding and Receptor Complex Assembly
In simple terms: Activin binds to type II receptors on the cell surface, which then recruit and activate type I receptors.
Activin, a dimeric ligand, binds with high affinity to type II receptors (ACVR2A or ACVR2B), which are constitutively active kinases. This binding induces conformational changes that allow the type II receptor to phosphorylate and activate type I receptors (ALK4 or ALK7). The activated type I receptor then propagates the signal intracellularly. This step is essential for initiating downstream signaling and is a target for inhibitors like SB-431542.
Intracellular Signaling via SMAD Proteins
In simple terms: Activated type I receptors phosphorylate SMAD proteins, which move to the nucleus to turn genes on or off.
Once activated, type I receptors phosphorylate receptor-regulated SMADs (SMAD2 and SMAD3). Phosphorylated SMAD2/3 form complexes with SMAD4 and translocate to the nucleus, where they regulate transcription of target genes. This canonical pathway is central to activin receptor activity and is modulated by various cofactors and inhibitors.
Non-Canonical Signaling Branches
In simple terms: Activin receptors can also activate other signaling molecules besides SMADs, such as MAP kinases.
In addition to SMAD signaling, activin receptors can activate non-canonical pathways including MAPK, PI3K/AKT, and Rho GTPases. These branches contribute to context-dependent cellular responses and crosstalk with other signaling networks. For example, ALK7 signaling has been linked to metabolic regulation.
Regulation by Endogenous Inhibitors
In simple terms: Proteins like DLK1 and follistatin can block activin receptor activity by preventing ligand-receptor interaction.
Endogenous inhibitors such as DLK1 and follistatin negatively regulate activin receptor activity. DLK1, a transmembrane protein, can bind to activin receptors and inhibit signaling, as revealed by recent structural studies. This regulation is crucial for fine-tuning signaling strength and duration in physiological contexts.
Pharmacological Modulation
In simple terms: Small molecules like SB-431542 can selectively inhibit activin receptor kinases.
SB-431542 is a potent and specific inhibitor of ALK4, ALK5, and ALK7, blocking activin receptor activity. It is widely used to dissect activin signaling in vitro and in vivo. Other inhibitors like dalantercept target activin receptors for therapeutic purposes. These tools enable precise experimental control of the pathway.
Key Genes Involved in GO:0017002 activin receptor activity
The following genes encode key components of activin receptor signaling, including ligands, receptors, and intracellular transducers.
| Gene | Major Role | Research Relevance |
|---|---|---|
| ACVR2A | Type II activin receptor | Mediates activin binding and initiation of signaling |
| ACVR2B | Type II activin receptor | Blockade increases muscle mass |
| ACVR1B (ALK4) | Type I activin receptor | Phosphorylates SMAD2/3; inhibited by SB-431542 |
| ACVR1C (ALK7) | Type I activin receptor | Mediates activin E signaling; metabolic roles |
| INHBA | Activin A subunit | Ligand for activin receptors; involved in cancer and muscle |
| INHBB | Activin B subunit | Forms activin B and AB dimers |
| INHBE | Activin E subunit | Signals specifically through ALK7 |
| SMAD2 | Intracellular signal transducer | Phosphorylated by type I receptors |
| SMAD3 | Intracellular signal transducer | Forms complexes with SMAD4 |
| SMAD4 | Common SMAD | Translocates to nucleus to regulate transcription |
| DLK1 | Endogenous inhibitor | Inhibits activin receptor signaling |
| FST | Follistatin | Binds and neutralizes activin |
| GDF8 (Myostatin) | Related ligand | Blockade protects against muscle loss |
| BRCC3 | Regulator of ALK2 | Implicated in pulmonary hypertension |
| ALK2 (ACVR1) | Related type I receptor | Regulated by BRCC3 in vascular smooth muscle |
How Is activin receptor activity Regulated?
Activin receptor activity is tightly regulated at multiple levels. Extracellularly, ligand availability is controlled by binding proteins such as follistatin and DLK1, which sequester activin or block receptor interaction. At the membrane, receptor abundance and trafficking are modulated by endocytosis and degradation. Intracellularly, inhibitory SMADs (SMAD6/7) and phosphatases can attenuate signaling. Additionally, post-translational modifications of receptors, such as phosphorylation and ubiquitination, influence their activity. Pharmacological inhibitors like SB-431542 provide exogenous control. This multilayered regulation ensures appropriate signaling strength and duration in diverse physiological contexts.
activin receptor activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| ACVR2A/ACVR2B | Muscle wasting, metabolic disorders | Knockout mice, muscle-specific overexpression |
| ALK4 (ACVR1B) | Cancer, fibrosis | CRISPR knockout in cancer cell lines |
| ALK7 (ACVR1C) | Metabolic regulation, cancer | Point mutation models to study ligand specificity |
| DLK1 | Developmental disorders, cancer | Knock-in of DLK1 mutants |
| BRCC3 | Pulmonary hypertension | Vascular smooth muscle cell knockout |
Cancer
Dysregulated activin receptor signaling is implicated in various cancers, where it can promote tumor growth, invasion, and metastasis or act as a tumor suppressor depending on context. For example, activin A signaling through ALK4/ALK7 has been linked to pancreatic and breast cancer progression. Targeting activin receptors with inhibitors like dalantercept is being explored as an anti-cancer strategy.
Muscle Wasting and Metabolic Disorders
Activin receptor signaling, particularly through ACVR2A/ACVR2B, regulates muscle mass. Blockade of these receptors increases muscle mass and strength but may compromise glycemic control. In obesity, GDF8 and activin A blockade protects against GLP-1-induced muscle loss while enhancing fat loss. These findings highlight the therapeutic potential of modulating activin receptor activity in metabolic diseases.
Pulmonary Hypertension
BRCC3 regulates ALK2, a type I receptor related to activin receptors, in vascular smooth muscle cells, implicating activin-like signaling in pulmonary hypertension. This suggests that targeting activin receptor pathways may offer therapeutic benefits for vascular remodeling diseases.
Reproductive Disorders
Activin receptor signaling is critical for reproductive function, including folliculogenesis and spermatogenesis. Dysregulation can lead to infertility and reproductive disorders. Understanding the molecular mechanisms of activin receptor activity is essential for developing treatments.
From activin receptor activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does gene X regulate activin receptor signaling? | CRISPR knockout in cell lines (e.g., HepG2) |
| What is the effect of a specific point mutation in ACVR2A? | Point mutation knock-in via CRISPR |
| How does overexpression of activin A affect muscle mass? | Transgenic overexpression in mice |
| Can we tag the receptor to track localization? | Knock-in of fluorescent tag (e.g., GFP) |
| What is the role of ALK7 in metabolic tissues? | Tissue-specific knockout |
| Does inhibition of activin receptors improve cancer outcomes? | Xenograft models with receptor inhibitors |
How to Study the activin receptor activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| CRISPR knockout screen | Gene essentiality for pathway activity | Identify novel regulators |
| Phosphoproteomics | Phosphorylation changes | Map signaling networks |
| RNA-seq | Transcriptional changes | Identify target genes |
| Live-cell imaging | Receptor localization and dynamics | Study trafficking and signaling |
| Western blot | Protein expression and phosphorylation | Validate pathway activation |
| Luciferase reporter assay | SMAD transcriptional activity | Measure pathway activity |
| Co-immunoprecipitation | Protein-protein interactions | Study receptor complexes |
| Flow cytometry | Cell surface receptor levels | Quantify receptor expression |
CRISPR-Cas9 Knockout Screening
Genome-wide CRISPR knockout screens can identify genes that regulate activin receptor activity. For example, a screen in vascular smooth muscle cells identified BRCC3 as a regulator of ALK2. This method allows unbiased discovery of novel pathway components and is applicable to various cell types.
Phosphoproteomics
Phosphoproteomics can quantify changes in phosphorylation events downstream of activin receptor activation. This approach reveals immediate signaling events and can identify novel substrates. It is particularly useful for dissecting non-canonical branches.
Transcriptomics (RNA-seq)
RNA sequencing measures gene expression changes induced by activin receptor signaling. It can identify transcriptional targets of SMAD2/3 and assess pathway activity in disease models. This method is high-throughput and quantitative.
Live-Cell Imaging
Live-cell imaging with fluorescently tagged receptors or SMAD proteins allows real-time visualization of receptor trafficking and signaling dynamics. This technique provides spatial and temporal resolution of activin receptor activity.
How CRISPR Can Be Used to Study GO:0017002 activin receptor activity
Knockout
CRISPR knockout of activin receptor genes (e.g., ACVR2A, ACVR2B, ALK4) abolishes signaling and allows assessment of their specific roles. For example, knockout of ACVR2A/ACVR2B in mice increases muscle mass. In cell lines, knockout of ALK4 blocks activin-induced SMAD phosphorylation. This approach is fundamental for loss-of-function studies.
Point Mutation
CRISPR point mutation can introduce specific amino acid changes to study receptor function. For instance, mutating the kinase domain of ALK7 can reveal residues critical for activin E signaling. This precision allows structure-function analysis without altering other domains.
Knock-in
Knock-in of tags (e.g., GFP, HA) or reporter genes enables visualization and tracking of activin receptors. For example, knocking in a fluorescent tag on ACVR2A allows live-cell imaging of receptor trafficking. Knock-in of disease-associated mutations can model human disorders.
Overexpression
CRISPR activation (CRISPRa) or transgenic overexpression can increase activin receptor levels to study gain-of-function effects. Overexpression of activin A in mice leads to muscle wasting and cachexia. This approach is useful for modeling diseases with enhanced signaling.
How EDITGENE Supports activin receptor activity Research
Researchers studying activin receptor activity-related genes often need to determine whether a candidate gene is causally involved in signaling, disease, or development. EDITGENE provides comprehensive CRISPR-based services to generate precisely engineered cell and animal models, accelerating functional validation and therapeutic discovery.
Contact EDITGENE today to design your custom CRISPR model for activin receptor activity research.
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| ACVR1B Knockout HEK293 Cell Line | EDJ-KQ362 | Human | 91 | Details Get a Quote |
| ACVR1C Knockout HEK293 Cell Line | EDJ-KQ363 | Human | 130399 | Details Get a Quote |
| ACVR2B Knockout HEK293 Cell Line | EDJ-KQ364 | Human | 93 | Details Get a Quote |
| ACVR2A Knockout HEK293 Cell Line | EDC07756 | Human | 92 | Details Get a Quote |
| ACVR1B Knockout A-549 Cell Line | EDJ-KQ17978 | Human | 91 | Details Get a Quote |
| ACVR1B Knockout HCT 116 Cell Line | EDJ-KQ18551 | Human | 91 | Details Get a Quote |
| ACVR1B Knockout HeLa Cell Line | EDJ-KQ18552 | Human | 91 | Details Get a Quote |
| ACVR2B Knockout A-549 Cell Line | EDJ-KQ18553 | Human | 93 | Details Get a Quote |
| ACVR2B Knockout HCT 116 Cell Line | EDJ-KQ18554 | Human | 93 | Details Get a Quote |
| ACVR2B Knockout HeLa Cell Line | EDJ-KQ18555 | Human | 93 | Details Get a Quote |
| ACVR2A Knockout A-549 Cell Line | EDJ-KQ23897 | Human | 92 | Details Get a Quote |
| ACVR2A Knockout HCT 116 Cell Line | EDJ-KQ23898 | Human | 92 | Details Get a Quote |
| ACVR2A Knockout HeLa Cell Line | EDJ-KQ23899 | Human | 92 | Details Get a Quote |
| ACVR1C Knockout HeLa Cell Line | EDJ-KQ58277 | Human | 130399 | Details Get a Quote |
| ACVR1C Knockout A-549 Cell Line | EDJ-KQ66765 | Human | 130399 | Details Get a Quote |
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Frequently Asked Questions About activin receptor activity
What is activin receptor activity?
Activin receptor activity (GO:0017002) is the molecular function of binding activin and transmitting a signal across the cell membrane to initiate a cellular response.
What genes are involved in activin receptor activity?
Key genes include ACVR2A, ACVR2B (type II receptors), ACVR1B (ALK4), ACVR1C (ALK7) (type I receptors), and downstream SMAD2/3/4.
What diseases are associated with activin receptor activity?
Dysregulation is linked to cancer, muscle wasting, metabolic disorders, pulmonary hypertension, and reproductive disorders.
How can I study activin receptor activity in the lab?
Common methods include CRISPR knockout, phosphoproteomics, RNA-seq, and live-cell imaging.
What are the inhibitors of activin receptors?
SB-431542 inhibits ALK4/5/7, and dalantercept is a therapeutic inhibitor.
What is the role of ALK7 in activin signaling?
ALK7 mediates activin E signaling and has metabolic functions.
How does DLK1 regulate activin receptors?
DLK1 binds to activin receptors and inhibits signaling, acting as an endogenous negative regulator.
Can CRISPR be used to study activin receptor function?
Yes, CRISPR knockout, knock-in, and overexpression models are widely used to dissect receptor function.
What is the link between activin receptors and muscle mass?
Blockade of ACVR2A/ACVR2B increases muscle mass and strength, but may affect glycemic control.
What is the clinical potential of targeting activin receptors?
Targeting activin receptors shows promise for cancer, muscle wasting, and metabolic diseases.
Conclusion
Activin receptor activity (GO:0017002) is a fundamental molecular function that mediates diverse physiological and pathological processes. Its core mechanism involves ligand-induced assembly of type I and type II receptor complexes, activation of SMAD and non-SMAD pathways, and tight regulation by endogenous inhibitors. Dysregulation contributes to cancer, muscle wasting, metabolic disorders, and pulmonary hypertension, making it a compelling therapeutic target. Advances in CRISPR-based models and high-throughput methods continue to unravel the complexities of this pathway, offering new opportunities for drug discovery and precision medicine.
References
- 1. Vestal KA et al.. 2024. Activin E is a transforming growth factor β ligand that signals specifically through activin receptor-like kinase 7.. Biochem J 481(7):547-564 PMID: 38533769
- 2. Shen H et al.. 2024. BRCC3 Regulation of ALK2 in Vascular Smooth Muscle Cells: Implication in Pulmonary Hypertension.. Circulation 150(2):132-150 PMID: 38557054
- 3. Gupta S et al.. 2015. Activin receptor inhibitors--dalantercept.. Curr Oncol Rep 17(4):14 PMID: 25708802
- 4. Abe Y et al.. 2004. Activin receptor signaling.. Growth Factors 22(2):105-10 PMID: 15253386
- 5. Carlsson M et al.. 2025. Activin receptor type IIA/IIB blockade increases muscle mass and strength, but compromises glycemic control in mice.. Mol Metab 102:102261 PMID: 41022302
- 6. Inman GJ et al.. 2002. SB-431542 is a potent and specific inhibitor of transforming growth factor-beta superfamily type I activin receptor-like kinase (ALK) receptors ALK4, ALK5, and ALK7.. Mol Pharmacol 62(1):65-74 PMID: 12065756
- 7. Mastaitis JW et al.. 2025. GDF8 and activin A blockade protects against GLP-1-induced muscle loss while enhancing fat loss in obese male mice and non-human primates.. Nat Commun 16(1):4377 PMID: 40360507
- 8. Antfolk D et al.. 2025. Molecular mechanism of Activin receptor inhibition by DLK1.. Nat Commun 16(1):5976 PMID: 40593645
