GO:0035385 Roundabout signaling pathway: Mechanism, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0035385 (Roundabout signaling pathway) describes the molecular signal initiated when a SLIT ligand binds a ROBO family receptor on a target cell, leading to regulation of downstream processes such as transcription.
• SLIT-ROBO signaling is a canonical axon guidance and cell migration pathway that also controls angiogenesis, immune cell behavior, and organ fibrosis.
• Dysregulated Roundabout signaling is implicated in glioma progression, chronic obstructive pulmonary disease (COPD), liver fibrosis, and pathological ocular neovascularization.
• ROBO1 and ROBO2 are the principal receptors, while SLIT2 and SLIT3 are the best-characterized ligands in mammals.
• The pathway is context-dependent: it can inhibit or promote cell motility depending on receptor isoform, co-receptors, and tissue environment.
• CRISPR knockout, point-mutation, knock-in, and overexpression models are essential tools for dissecting SLIT-ROBO gene function in disease-relevant cell types.
Description
The Roundabout signaling pathway (GO:0035385) is a conserved biological process triggered when a SLIT protein binds to a Roundabout (ROBO) family receptor on the surface of a target cell, culminating in regulation of downstream cellular events such as transcription. First characterized in axon guidance, this pathway is now recognized as a central regulator of cell migration, adhesion, and tissue patterning across multiple organ systems. Understanding GO:0035385 is therefore important for researchers studying neurodevelopment, vascular biology, immunity, and fibrosis. The pathway has attracted increasing attention because its components are dysregulated in human diseases ranging from glioma to COPD and ocular neovascular disorders. This article synthesizes authoritative QuickGO annotation and verified PubMed literature to provide a research-grade overview of the Roundabout signaling pathway, its key genes, regulatory logic, disease links, and the CRISPR-based experimental models used to study it.
Roundabout signaling pathway At A Glance
| GO ID | GO:0035385 |
|---|---|
| GO term | Roundabout signaling pathway |
| Ontology | biological_process |
| Synonym | ROBO signaling pathway; ROBO/SLIT signaling pathway; Roundabout signalling pathway |
| Definition | The series of molecular signals initiated by a SLIT protein binding to a Roundabout (ROBO) family receptor on the surface of a target cell, and ending with the regulation of a downstream cellular process, e.g. transcription |
| Major function | Regulation of cell migration, axon guidance, adhesion, and transcription downstream of SLIT-ROBO engagement |
| Key ligands | SLIT1, SLIT2, SLIT3 |
| Key receptors | ROBO1, ROBO2, ROBO3, ROBO4 |
| Disease relevance | Glioma, COPD, liver fibrosis, ocular neovascularization |
What Is GO:0035385?
GO:0035385, the Roundabout signaling pathway, is defined as the series of molecular signals initiated by a SLIT protein binding to a Roundabout (ROBO) family receptor on the surface of a target cell, and ending with the regulation of a downstream cellular process, for example transcription. In practice, this means the pathway encompasses ligand-receptor recognition at the plasma membrane, intracellular signal transduction through ROBO cytoplasmic domains, and the resulting changes in gene expression or cytoskeletal behavior that alter cell function.
Why Is Roundabout signaling pathway Important in Cell Biology?
The Roundabout signaling pathway is important because it sits at the intersection of developmental patterning and adult tissue homeostasis, controlling how cells move, adhere, and respond to their environment. Its dysregulation contributes to major human diseases including glioma, chronic obstructive pulmonary disease, liver fibrosis, and pathological ocular neovascularization, making it a compelling target for mechanistic and therapeutic research. Because SLIT-ROBO signaling is highly context-dependent, precise genetic models are required to determine whether individual pathway components act causally in a given disease setting.
• Controls axon guidance and neuronal migration during nervous system development.
• Regulates angiogenesis and vascular patterning through ROBO4 and related receptors.
• Modulates immune cell trafficking and myeloid cell behavior in pathological neovascularization.
• Is implicated in glioma pathogenesis and represents a potential therapeutic axis.
• Is associated with COPD pathogenesis according to integrative bioinformatics analysis.
• Promotes liver fibrosis through activation of SLIT2-ROBO1 signaling.
• Influences fibroblast behavior and scarring potential across anatomical sites.
• Provides a model system for studying context-dependent signal transduction.
• Offers druggable targets, as shown by monoclonal antibodies blocking ROBO1 and ROBO2.
• Connects to broader cell-fate and transcriptional programs in development.
What Happens During Roundabout signaling pathway?
SLIT ligand binding to ROBO receptors
In simple terms: A SLIT protein docks onto a ROBO receptor on the cell surface, like a key fitting a lock.
The pathway begins when a secreted SLIT protein binds to a Roundabout (ROBO) family receptor on the surface of a target cell. This ligand-receptor interaction is the initiating event defined by GO:0035385 and is required for all downstream signaling. SLIT proteins are large secreted glycoproteins, and their binding to ROBO receptors triggers receptor activation and recruitment of intracellular effectors.
Receptor activation and intracellular signal transduction
In simple terms: Once the receptor is engaged, it transmits a signal inside the cell.
Following SLIT binding, ROBO receptors undergo conformational and biochemical changes that propagate the signal into the cytoplasm. ROBO cytoplasmic domains interact with adaptor and signaling molecules to relay the signal toward downstream effectors. This transduction step is context-dependent and can engage cytoskeletal regulators and transcriptional machinery depending on the cell type.
Regulation of downstream cellular processes
In simple terms: The signal changes what the cell does, such as moving, sticking, or switching genes on and off.
The pathway ends with regulation of a downstream cellular process, for example transcription. In neurons, this manifests as changes in growth cone guidance and migration. In non-neuronal cells, SLIT-ROBO signaling can alter adhesion, motility, and gene expression programs relevant to fibrosis and angiogenesis.
Context-dependent outcomes in different tissues
In simple terms: The same pathway can have different effects depending on the cell type.
Roundabout signaling is highly context-dependent: it can inhibit or promote cell motility depending on receptor isoform, co-receptors, and tissue environment. In glioma, pathway components are dysregulated in ways that support tumor pathogenesis. In liver fibrosis, activation of SLIT2-ROBO1 signaling promotes fibrotic responses. In ocular neovascularization, blocking ROBO1 and ROBO2 signaling targets pathological vessel formation through myeloid cells.
Key Genes Involved in GO:0035385 Roundabout signaling pathway
The following genes and proteins are central to the Roundabout signaling pathway (GO:0035385) and are frequently studied in mechanistic and disease-focused research.
| Gene | Major Role | Research Relevance |
|---|---|---|
| SLIT1 | Secreted ligand for ROBO receptors | Axon guidance and neuronal migration studies |
| SLIT2 | Secreted ligand for ROBO receptors | Liver fibrosis and cancer research |
| SLIT3 | Secreted ligand for ROBO receptors | Developmental and vascular biology studies |
| ROBO1 | Roundabout family receptor | Glioma, fibrosis, and antibody blockade studies |
| ROBO2 | Roundabout family receptor | Ocular neovascularization and axon guidance |
| ROBO3 | Roundabout family receptor | Neuronal circuit development |
| ROBO4 | Endothelial-enriched Roundabout receptor | Angiogenesis and vascular patterning |
| SRGAP1 | ROBO-associated GTPase-activating protein | Cytoskeletal regulation downstream of ROBO |
| SRGAP2 | ROBO-associated GTPase-activating protein | Neuronal migration and synapse studies |
| SRGAP3 | ROBO-associated GTPase-activating protein | Neuronal development research |
| ABL1 | Tyrosine kinase interacting with ROBO signaling | Cytoskeletal remodeling studies |
| DCC | Guidance receptor with context-dependent crosstalk | Axon guidance research |
| NCK1 | Adaptor protein in ROBO signaling | Signal transduction studies |
| NCK2 | Adaptor protein in ROBO signaling | Signal transduction studies |
| MYH9 | Non-muscle myosin heavy chain | Cytoskeletal and migration studies |
| CDC42 | Rho-family GTPase | Cytoskeletal dynamics downstream of ROBO |
| RAC1 | Rho-family GTPase | Cell migration and adhesion studies |
How Is Roundabout signaling pathway Regulated?
Roundabout signaling is regulated at multiple levels, including ligand availability, receptor expression and isoform usage, and intracellular adaptor availability. The pathway intersects with Rho-family GTPase signaling through SRGAP proteins and other effectors, which modulate cytoskeletal dynamics downstream of ROBO activation. In disease contexts, pathway activity can be modulated by the tissue microenvironment and by crosstalk with other signaling systems. Monoclonal antibodies that block ROBO1 and ROBO2 signaling have been shown to target pathological ocular neovascularization through myeloid cells, demonstrating that the pathway is pharmacologically tractable.
Roundabout signaling pathway and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| SLIT2 / ROBO1 | Liver fibrosis | Knockout or overexpression in hepatic stellate cell models |
| ROBO1 / ROBO2 | Ocular neovascularization | Antibody blockade in retinal neovascularization models |
| SLIT / ROBO pathway genes | Glioma | Knockout and overexpression in glioma cell lines |
| Roundabout pathway genes | COPD | Bioinformatics-guided validation in lung cell models |
| SLIT-ROBO components | Fibroblast scarring potential | Primary fibroblast knockout models |
Roundabout signaling in glioma
The SLIT/ROBO signaling pathway has an emerging role in glioma pathogenesis and is considered a potential therapeutic option. Dysregulation of pathway components in glioma supports the idea that Roundabout signaling contributes to tumor biology. Researchers use glioma models to dissect how SLIT and ROBO genes influence tumor cell behavior.
Roundabout signaling in COPD
Integrative bioinformatics analysis has implicated the Roundabout signaling pathway in the pathogenesis of chronic obstructive pulmonary disease (COPD). This suggests that SLIT-ROBO components may serve as biomarkers or mechanistic contributors in COPD. Experimental models of lung disease can be used to test whether pathway modulation alters disease phenotypes.
Roundabout signaling in liver fibrosis
Activation of SLIT2-ROBO1 signaling promotes liver fibrosis, linking the pathway directly to fibrotic disease mechanisms. This finding supports targeting SLIT2-ROBO1 as a potential antifibrotic strategy. Liver fibrosis models are used to study how pathway activation drives fibrogenic responses.
Roundabout signaling in ocular neovascularization
Monoclonal antibodies that block ROBO1 and ROBO2 signaling target pathological ocular neovascularization through myeloid cells. This demonstrates that the pathway is functionally important in vascular eye disease and that antibody-based blockade can modulate disease. These findings support further investigation of ROBO-directed therapeutics.
From Roundabout signaling pathway-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of ROBO1 alter cell migration? | ROBO1 knockout cell line |
| Does a specific ROBO point mutation disrupt ligand binding? | Point-mutation knock-in model |
| Does tagged ROBO receptor localize correctly? | Tagged knock-in of ROBO1 or ROBO2 |
| Does SLIT2 overexpression drive fibrosis? | SLIT2 overexpression in hepatic cells |
| Can ROBO blockade reduce neovascularization? | Antibody-treated ocular neovascularization model |
| Which pathway genes are dysregulated in COPD? | Bioinformatics plus knockout validation |
How to Study the Roundabout signaling pathway Process
| Method | What It Measures | Typical Application |
|---|---|---|
| RNA-seq | Differential gene expression | Pathway discovery in COPD and other diseases |
| CRISPR knockout | Loss-of-function phenotype | Testing causal roles of ROBO and SLIT genes |
| CRISPR point mutation | Effect of specific amino acid changes | Dissecting receptor-ligand interfaces |
| CRISPR knock-in | Tagged or reporter protein expression | Localization and interaction studies |
| Overexpression | Gain-of-function phenotype | Testing SLIT2-driven fibrosis |
| Antibody blockade | Extracellular receptor inhibition | Ocular neovascularization models |
| Bioinformatics enrichment | Pathway-level dysregulation | Integrative analysis of disease datasets |
Transcriptomic and bioinformatics analysis
Integrative bioinformatics analysis has been used to implicate the Roundabout signaling pathway in COPD pathogenesis, demonstrating the value of transcriptomic approaches for pathway discovery. RNA-seq and pathway enrichment can identify SLIT-ROBO components that are differentially expressed in disease versus control samples. These methods are often the first step before functional validation.
Genetic perturbation with CRISPR
CRISPR knockout, point-mutation, knock-in, and overexpression models allow researchers to test causal roles of SLIT and ROBO genes. Such models are essential because the pathway is context-dependent and can have opposite effects in different tissues. Antibody blockade studies further complement genetic approaches by targeting receptor function extracellularly.
Protein interaction and signaling assays
Biochemical assays can measure SLIT-ROBO binding and downstream adaptor recruitment. GTPase and cytoskeletal assays can assess signaling through SRGAP and Rho-family effectors. These methods help define the molecular steps that connect receptor activation to cellular outcomes.
Disease-relevant functional models
Liver fibrosis models have been used to show that activation of SLIT2-ROBO1 signaling promotes fibrosis. Ocular neovascularization models have been used to test ROBO1/ROBO2 blocking antibodies. Glioma models are used to study the pathway's role in tumor pathogenesis.
How CRISPR Can Be Used to Study GO:0035385 Roundabout signaling pathway
Knockout
CRISPR knockout of ROBO1, ROBO2, SLIT2, or related genes can reveal loss-of-function phenotypes in migration, adhesion, and transcription. Knockout models are particularly useful for testing whether a pathway component is required for a disease phenotype. For example, knocking out ROBO receptors can test their role in pathological neovascularization.
Point Mutation
Point-mutation models allow precise testing of residues involved in SLIT-ROBO binding or downstream adaptor recruitment. Such models are valuable when a complete knockout is lethal or when domain-specific functions must be separated. They can also model disease-associated variants in pathway genes.
Knock-in
Knock-in of tags or reporters into ROBO or SLIT loci enables visualization and biochemical isolation of pathway components. Tagged knock-in models help track receptor localization and interactions in live or fixed cells. They are also useful for studying isoform-specific functions.
Overexpression
Overexpression of SLIT2 or ROBO receptors can drive gain-of-function phenotypes such as enhanced fibrosis. Overexpression models complement knockout studies by revealing whether increased pathway activity is sufficient to cause a phenotype. They are also used to test therapeutic hypotheses in disease-relevant cells.
How EDITGENE Supports Roundabout signaling pathway Research
Researchers studying Roundabout signaling pathway-related genes often need to determine whether a candidate gene is causally involved in a given phenotype, and CRISPR-based models provide the most direct way to test this. EDITGENE supports this work with knockout, point-mutation, knock-in, overexpression cell models, and CRISPR library screening combined with bioinformatics analysis.
Contact EDITGENE today to design your custom CRISPR model for Roundabout signaling pathway research.
Frequently Asked Questions About Roundabout signaling pathway
What is the Roundabout signaling pathway?
It is the biological process (GO:0035385) initiated when a SLIT protein binds a ROBO family receptor on a target cell, leading to regulation of downstream cellular processes such as transcription.
What genes are involved in Roundabout signaling?
Key genes include the ligands SLIT1, SLIT2, and SLIT3, the receptors ROBO1, ROBO2, ROBO3, and ROBO4, and downstream effectors such as SRGAP family members.
What is the GO ID for Roundabout signaling pathway?
The GO ID is GO:0035385, with synonyms including ROBO signaling pathway and ROBO/SLIT signaling pathway.
How is Roundabout signaling linked to cancer?
The SLIT/ROBO pathway has an emerging role in glioma pathogenesis and is considered a potential therapeutic option.
Is Roundabout signaling involved in COPD?
Yes, integrative bioinformatics analysis has implicated the Roundabout signaling pathway in the pathogenesis of COPD.
What role does SLIT2-ROBO1 play in liver fibrosis?
Activation of SLIT2-ROBO1 signaling promotes liver fibrosis, supporting it as a potential antifibrotic target.
Can Roundabout signaling be targeted therapeutically?
Monoclonal antibodies that block ROBO1 and ROBO2 signaling target pathological ocular neovascularization through myeloid cells, showing therapeutic potential.
What experimental models are used to study Roundabout signaling?
CRISPR knockout, point-mutation, knock-in, and overexpression cell models, as well as antibody blockade and bioinformatics approaches, are commonly used.
Which receptors mediate Roundabout signaling?
ROBO1, ROBO2, ROBO3, and ROBO4 are the principal Roundabout family receptors.
Why is Roundabout signaling context-dependent?
The pathway can inhibit or promote cell motility depending on receptor isoform, co-receptors, and tissue environment, making outcomes highly context-specific.
Conclusion
The Roundabout signaling pathway (GO:0035385) is a conserved and context-dependent process that links SLIT ligand binding to ROBO receptors with downstream changes in transcription, migration, and adhesion. Its involvement in glioma, COPD, liver fibrosis, and ocular neovascularization makes it a high-value research area for both mechanistic and translational studies. CRISPR-based knockout, point-mutation, knock-in, and overexpression models, combined with bioinformatics and functional assays, provide the tools needed to dissect pathway causality and identify therapeutic opportunities.
References
- 1. Markouli M et al.. 2024. Emerging Role of the Slit/Roundabout (Robo) Signaling Pathway in Glioma Pathogenesis and Potential Therapeutic Options.. Biomolecules 14(10) PMID: 39456164
- 2. Lin YZ et al.. 2019. Roundabout signaling pathway involved in the pathogenesis of COPD by integrative bioinformatics analysis.. Int J Chron Obstruct Pulmon Dis 14:2145-2162 PMID: 31571851
- 3. Griffin MF et al.. 2026. Fibroblasts of disparate developmental origins harbor anatomically variant scarring potential.. Cell 189(3):783-799.e20 PMID: 41576949
- 5. Geraldo LH et al.. 2024. Monoclonal antibodies that block Roundabout 1 and 2 signaling target pathological ocular neovascularization through myeloid cells.. Sci Transl Med 16(774):eadn8388 PMID: 39565875
- 6. Chang J et al.. 2015. Activation of Slit2-Robo1 signaling promotes liver fibrosis.. J Hepatol 63(6):1413-20 PMID: 26264936
- 7. Blockus H et al.. 2016. Slit-Robo signaling.. Development 143(17):3037-44 PMID: 27578174
- 8. Romanov RA et al.. 2020. Molecular design of hypothalamus development.. Nature 582(7811):246-252 PMID: 32499648
