GO:0071526 semaphorin-plexin signaling pathway: Axon Guidance and Beyond, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0071526 describes the molecular signaling cascade triggered when a semaphorin ligand binds to a receptor complex composed of a plexin and a neuropilin.
• Semaphorin-plexin signaling is best known for repulsive axon guidance during neural development, but it also controls immune cell trafficking, epithelial morphogenesis, and tumor progression.
• Mutations in semaphorin-plexin pathway genes cause X-linked intellectual disability and other neurodevelopmental disorders.
• The pathway regulates mitotic spindle orientation in epithelial cells, linking it to tissue repair and cancer.
• Semaphorin-plexin signaling is dysregulated in glioblastoma, where it promotes invasion, angiogenesis, and treatment resistance.
• CRISPR-based knockout, point mutation, knock-in, and overexpression models are essential for dissecting semaphorin-plexin gene function in health and disease.
Description
The semaphorin-plexin signaling pathway (GO:0071526) is a conserved biological process that begins when a secreted or membrane-bound semaphorin ligand binds to a receptor complex composed of a plexin and a neuropilin. This interaction triggers intracellular signaling that classically mediates repulsive axon guidance, but it also governs diverse processes such as immune regulation, epithelial morphogenesis, and tumor progression. The pathway is essential for normal development and tissue homeostasis, and its dysregulation is linked to neurological disorders, autoimmune conditions, and cancer. Researchers study this pathway to understand how cells interpret guidance cues and to develop therapeutic strategies for diseases where semaphorin-plexin signaling is altered. The availability of CRISPR-based gene editing tools now allows precise functional interrogation of pathway components in relevant cell models.
semaphorin-plexin signaling pathway At A Glance
| GO ID | GO:0071526 |
|---|---|
| GO term | semaphorin-plexin signaling pathway |
| Ontology | biological_process |
| Synonym | semaphorin-plexin signalling pathway |
| Major function | Transduces signals from semaphorin ligands via plexin-neuropilin receptor complexes to control axon guidance, cell migration, immune regulation, and tissue morphogenesis |
| Key ligands | Semaphorins (e.g., SEMA3A, SEMA4D, SEMA7A) |
| Key receptors | Plexins (e.g., PLXNA1, PLXNA2, PLXNB1) and neuropilins (NRP1, NRP2) |
| Downstream effectors | Rho GTPases, Rasal1, and cytoskeletal regulators |
| Associated diseases | X-linked intellectual disability, cancer, peptic ulcer disease, atopic dermatitis |
What Is GO:0071526?
According to the Gene Ontology, GO:0071526 (semaphorin-plexin signaling pathway) is defined as the series of molecular signals generated as a consequence of a semaphorin receptor (composed of a plexin and a neurophilin) binding to a semaphorin ligand. In simpler terms, it is the entire cellular response that occurs after a semaphorin molecule docks onto its receptor complex, leading to changes in cell behavior such as repulsion, migration, or growth cone collapse.
Why Is semaphorin-plexin signaling pathway Important in Cell Biology?
Semaphorin-plexin signaling is a fundamental mechanism that shapes neural circuits, regulates immune responses, and maintains tissue architecture. Its dysfunction contributes to a wide range of human pathologies, including neurodevelopmental disorders, autoimmune diseases, and cancer. Understanding this pathway at the molecular level is therefore critical for identifying therapeutic targets and developing precision medicine approaches.
• Controls axon guidance and neural circuit formation during development.
• Regulates immune cell activation, trafficking, and cytokine production.
• Mutations cause X-linked intellectual disability syndrome.
• Inhibits gastrin expression and protects against peptic ulcers.
• Implicated in atopic dermatitis via IL-5 induction.
• Promotes tumor invasion, angiogenesis, and treatment resistance in glioblastoma.
• Controls mitotic spindle orientation during epithelial morphogenesis and repair.
• Provides structural insights into receptor-ligand recognition for drug design.
• Links immune semaphorin/plexin signaling to carcinogenesis.
What Happens During semaphorin-plexin signaling pathway?
Ligand binding and receptor complex formation
In simple terms: A semaphorin molecule binds to a receptor made of plexin and neuropilin proteins on the cell surface.
The pathway is initiated when a semaphorin ligand, such as SEMA3A or SEMA4D, binds to a receptor complex composed of a plexin and a neuropilin. Structural studies have revealed that semaphorins dimerize and engage the extracellular domains of plexins and neuropilins, leading to receptor clustering and activation. This binding event is highly specific and is the first committed step in the signaling cascade.
Plexin activation and intracellular signaling
In simple terms: Once the ligand is bound, the plexin receptor changes shape and activates signaling inside the cell.
Ligand binding induces conformational changes in the plexin intracellular domain, which contains a GTPase-activating protein (GAP) homology region. This leads to activation of downstream effectors such as Rho GTPases, which regulate cytoskeletal dynamics. In some contexts, plexin signaling also recruits Rasal1 to inhibit gastrin expression.
Cytoskeletal remodeling and cell repulsion
In simple terms: The signal causes the cell's skeleton to rearrange, often making the cell move away or change shape.
Activated plexins modulate actin and microtubule dynamics through Rho GTPases and other regulators, leading to growth cone collapse in neurons or changes in cell polarity in epithelia. In epithelial cells, semaphorin-plexin signaling controls mitotic spindle orientation, which is essential for proper tissue morphogenesis and repair.
Integration with immune and metabolic pathways
In simple terms: The pathway also talks to the immune system and can affect how cells respond to their environment.
Semaphorin-plexin signaling is integrated with immune cell function, influencing T cell activation, cytokine production, and inflammatory responses. For example, dibutyl phthalate-induced atopic dermatitis involves semaphorin-plexin signaling and IL-5. Additionally, the pathway can inhibit gastrin expression via Rasal1, protecting against peptic ulcers.
Key Genes Involved in GO:0071526 semaphorin-plexin signaling pathway
The following genes encode core components and regulators of the semaphorin-plexin signaling pathway, all of which are actively studied in developmental biology, immunology, and cancer research.
| Gene | Major Role | Research Relevance |
|---|---|---|
| SEMA3A | Secreted semaphorin ligand | Axon guidance, immune regulation, cancer |
| SEMA4D | Transmembrane semaphorin ligand | Immune cell activation, tumor progression |
| SEMA7A | GPI-anchored semaphorin ligand | Immune regulation, neural development |
| PLXNA1 | Plexin receptor | Axon guidance, cancer |
| PLXNA2 | Plexin receptor | Neural development, intellectual disability |
| PLXNB1 | Plexin receptor | Epithelial morphogenesis, cancer |
| PLXNB2 | Plexin receptor | Immune regulation, tumor angiogenesis |
| NRP1 | Neuropilin co-receptor | VEGF signaling, axon guidance, cancer |
| NRP2 | Neuropilin co-receptor | Lymphatic development, tumor progression |
| RASAL1 | Ras GAP downstream of plexin | Gastrin inhibition, peptic ulcer protection |
| RHOA | Rho GTPase effector | Cytoskeletal remodeling, cell repulsion |
| ROCK1 | Rho kinase effector | Actin dynamics, growth cone collapse |
| CRMP2 | Collapsin response mediator protein | Axon guidance, microtubule regulation |
| FARP2 | GEF for Rac1 downstream of plexin | Semaphorin-induced growth cone collapse |
| IL5 | Cytokine induced by semaphorin-plexin signaling | Atopic dermatitis, allergic inflammation |
How Is semaphorin-plexin signaling pathway Regulated?
Semaphorin-plexin signaling is regulated at multiple levels, including ligand availability, receptor expression, and post-translational modifications. Neuropilins act as essential co-receptors that enhance ligand binding specificity. Downstream, Rho GTPases and their regulators, such as Rasal1, modulate signal strength and duration. In immune cells, cytokines such as IL-5 can be induced by semaphorin-plexin signaling, creating feedback loops. Additionally, the pathway cross-talks with other signaling cascades, including VEGF and integrin signaling, to fine-tune cellular responses.
semaphorin-plexin signaling pathway and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| PLXNA2 | X-linked intellectual disability | Knockout mouse, patient-derived iPSCs |
| SEMA4D | Glioblastoma invasion and angiogenesis | Orthotopic xenograft, CRISPR KO in glioblastoma cell lines |
| RASAL1 | Peptic ulcer disease | Rasal1 knockout mouse, gastric organoids |
| SEMA3A | Atopic dermatitis | Knockout mouse, skin explants |
| PLXNB1 | Epithelial morphogenesis and repair | Conditional knockout mouse, 3D epithelial cultures |
Neurodevelopmental disorders
Mutations in semaphorin-plexin pathway genes, particularly PLXNA2 and SEMA3A, have been linked to X-linked intellectual disability syndrome. These mutations disrupt axon guidance and synaptic connectivity, leading to cognitive deficits.
Cancer
Semaphorin-plexin signaling is dysregulated in multiple cancers, including glioblastoma, where it promotes tumor invasion, angiogenesis, and resistance to therapy. Immune semaphorin/plexin signaling also contributes to carcinogenesis by modulating the tumor microenvironment.
Inflammatory and immune disorders
Dibutyl phthalate exposure induces atopic dermatitis through semaphorin-plexin signaling and IL-5 production. The pathway also regulates immune cell trafficking and activation, implicating it in autoimmune diseases.
Gastrointestinal disease
A semaphorin-plexin-Rasal1 signaling axis inhibits gastrin expression and protects against peptic ulcers. Loss of this regulation can lead to excessive gastrin secretion and ulcer formation.
From semaphorin-plexin signaling pathway-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of PLXNA2 cause axon guidance defects? | PLXNA2 knockout mouse or zebrafish |
| Can point mutations in SEMA3A mimic human intellectual disability? | CRISPR knock-in of patient mutations in iPSCs |
| How does SEMA4D promote glioblastoma invasion? | SEMA4D overexpression in glioblastoma cell lines |
| What is the role of Rasal1 in gastrin regulation? | Rasal1 knockout mouse and gastric organoids |
| Does semaphorin-plexin signaling control spindle orientation? | PLXNB1 knockout in 3D epithelial cultures |
| Can tagged plexin receptors reveal real-time signaling dynamics? | Knock-in of fluorescent tags at endogenous PLXNA1 locus |
How to Study the semaphorin-plexin signaling pathway Process
| Method | What It Measures | Typical Application |
|---|---|---|
| RNA-seq | Global transcriptomic changes | Identifying downstream targets of semaphorin-plexin signaling |
| Proteomics | Protein expression and modifications | Detecting pathway-induced signaling complexes |
| Live-cell imaging | Real-time receptor dynamics | Visualizing plexin trafficking and cytoskeletal changes |
| Growth cone collapse assay | Neuronal repulsion | Assessing semaphorin function in axon guidance |
| Immune cell migration assay | Chemotaxis and immune regulation | Studying semaphorin-plexin roles in immunity |
| CRISPR knockout screen | Gene essentiality and pathway regulators | Discovering novel therapeutic targets |
| Bioinformatics pathway analysis | Network and enrichment analysis | Integrating multi-omics data to map signaling |
Transcriptomic and proteomic profiling
RNA-seq and mass spectrometry can identify global changes in gene and protein expression upon semaphorin-plexin pathway activation or perturbation. These methods help uncover downstream effectors and feedback mechanisms.
Imaging and live-cell analysis
Fluorescence microscopy and live-cell imaging of tagged pathway components, such as GFP-tagged plexins, allow visualization of receptor trafficking and cytoskeletal dynamics. This is critical for understanding spatial and temporal aspects of signaling.
Functional assays
Growth cone collapse assays, immune cell migration assays, and epithelial spindle orientation assays are used to measure pathway activity. These phenotypic readouts are essential for validating gene function.
CRISPR screening and bioinformatics
Genome-wide CRISPR knockout screens combined with bioinformatics can identify novel regulators of semaphorin-plexin signaling. This approach is powerful for discovering therapeutic targets in cancer and immune disorders.
How CRISPR Can Be Used to Study GO:0071526 semaphorin-plexin signaling pathway
Knockout
CRISPR knockout of semaphorin-plexin pathway genes, such as PLXNA2 or SEMA4D, allows researchers to study loss-of-function phenotypes in cell models and animal models. This is particularly useful for validating gene function in axon guidance, immune regulation, and cancer.
Point Mutation
Introducing patient-specific point mutations into genes like SEMA3A or PLXNA2 using CRISPR base editing or homology-directed repair can model human neurodevelopmental disorders. These models help dissect the molecular consequences of specific mutations.
Knock-in
Knock-in of fluorescent tags or epitope tags at endogenous loci, such as PLXNA1-GFP, enables real-time tracking of receptor localization and signaling dynamics. This approach is valuable for understanding spatiotemporal regulation of the pathway.
Overexpression
CRISPR activation or lentiviral overexpression of semaphorin ligands like SEMA4D can model gain-of-function states observed in cancer and immune disorders. Overexpression models are useful for studying pathway-driven tumor invasion and angiogenesis.
How EDITGENE Supports semaphorin-plexin signaling pathway Research
Researchers studying semaphorin-plexin signaling pathway-related genes often need to determine whether a candidate gene is causally involved in a specific biological process or disease. This requires precise genetic manipulation, which can be achieved through CRISPR-based knockout, point mutation, knock-in, or overexpression models. EDITGENE provides end-to-end services to generate these models and support downstream functional studies.
Contact EDITGENE today to design your custom CRISPR model for semaphorin-plexin signaling pathway research.
Frequently Asked Questions About semaphorin-plexin signaling pathway
What is the semaphorin-plexin signaling pathway?
It is a biological process (GO:0071526) triggered when a semaphorin ligand binds to a plexin-neuropilin receptor complex, leading to diverse cellular responses such as axon guidance and immune regulation.
What genes are involved in semaphorin-plexin signaling?
Key genes include SEMA3A, SEMA4D, PLXNA1, PLXNA2, PLXNB1, NRP1, NRP2, and RASAL1.
What diseases are associated with semaphorin-plexin signaling?
It is linked to X-linked intellectual disability, glioblastoma, peptic ulcers, and atopic dermatitis.
How does semaphorin-plexin signaling control axon guidance?
Semaphorins act as repulsive cues that cause growth cone collapse through plexin-mediated cytoskeletal rearrangements.
What is the role of plexin in semaphorin signaling?
Plexins are the primary receptors that bind semaphorins and transduce signals intracellularly via their GAP domain.
What is the role of neuropilin in semaphorin signaling?
Neuropilins are essential co-receptors that enhance ligand binding specificity and are required for signaling.
How can CRISPR be used to study semaphorin-plexin signaling?
CRISPR knockout, point mutation, knock-in, and overexpression models allow precise functional interrogation of pathway genes.
What are the downstream effectors of semaphorin-plexin signaling?
Rho GTPases, Rasal1, and CRMP2 are key downstream effectors that regulate cytoskeletal dynamics and gene expression.
Is semaphorin-plexin signaling involved in cancer?
Yes, it promotes tumor invasion, angiogenesis, and treatment resistance, particularly in glioblastoma.
What methods are used to study semaphorin-plexin signaling?
Common methods include RNA-seq, proteomics, live-cell imaging, growth cone collapse assays, and CRISPR screens.
Conclusion
The semaphorin-plexin signaling pathway (GO:0071526) is a versatile and critical biological process that governs axon guidance, immune function, epithelial morphogenesis, and cancer progression. Its dysregulation underlies numerous human diseases, making it a prime target for therapeutic intervention. Advances in CRISPR gene editing now enable precise modeling of pathway components, accelerating both basic discovery and translational research.
References
- 1. Steele JL et al.. 2022. Semaphorin-Plexin Signaling: From Axonal Guidance to a New X-Linked Intellectual Disability Syndrome.. Pediatr Neurol 126:65-73 PMID: 34740135
- 2. Xu R et al.. 2022. A semaphorin-plexin-Rasal1 signaling pathway inhibits gastrin expression and protects against peptic ulcers.. Sci Transl Med 14(654):eabf1922 PMID: 35857828
- 3. Kang MJ et al.. 2025. Dibutyl phthalate induces atopic dermatitis via semaphorin-plexin signaling and IL-5: ECHO-COCOA study.. Pediatr Allergy Immunol 36(10):e70224 PMID: 41085243
- 4. Takamatsu H et al.. 2012. Diverse roles for semaphorin-plexin signaling in the immune system.. Trends Immunol 33(3):127-35 PMID: 22325954
- 5. Prajapati S et al.. 2026. Targeting Semaphorin-plexin Signaling in Glioblastoma: Implications for Tumor Invasion, Angiogenesis, and Treatment Resistance.. Curr Neurovasc Res PMID: 42634324
- 6. Xia J et al.. 2015. Semaphorin-Plexin Signaling Controls Mitotic Spindle Orientation during Epithelial Morphogenesis and Repair.. Dev Cell 33(3):299-313 PMID: 25892012
- 7. Janssen BJ et al.. 2010. Structural basis of semaphorin-plexin signalling.. Nature 467(7319):1118-22 PMID: 20877282
- 8. Műzes G et al.. 2014. Relation of immune semaphorin/plexin signaling to carcinogenesis.. Eur J Cancer Prev 23(5):469-76 PMID: 24922268
