GO:0035591 signaling adaptor activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0035591 signaling adaptor activity describes the binding activity of a molecule that physically brings together two or more signaling molecules so they can function coordinately, without the adaptor itself having catalytic activity.
• Adaptors are essential for assembling multiprotein signaling complexes such as the T cell receptor (TCR) signalosome and the mitochondrial antiviral signaling (MAVS) platform [1, 7].
• Classic adaptor proteins include LAT, SLP-76, GADS, STING, MAVS, TRAF6, and GABARAP, which nucleate signaling hubs in immune, inflammatory, and growth pathways [1, 4, 7, 8].
• Dysregulated adaptor activity contributes to autoimmunity, immunodeficiency, cancer, and neurodegeneration, making these proteins attractive drug targets [1, 3, 4].
• CRISPR knockout, point-mutation, knock-in, and overexpression models are the primary tools for dissecting adaptor function and validating therapeutic hypotheses [1, 4, 8].
• EDITGENE provides end-to-end CRISPR cell model and library screening services to study signaling adaptor activity in disease-relevant contexts.
Description
Signaling adaptor activity (GO:0035591) is a molecular function that enables a protein to bind two or more signaling molecules simultaneously, bringing them into proximity so they can act in a coordinated manner. Unlike kinases or phosphatases, adaptor proteins lack intrinsic catalytic activity; their role is purely organizational, serving as scaffolds that assemble signaling complexes. This function is critical for transmitting signals from cell surface receptors to downstream effectors in pathways such as T cell receptor (TCR) signaling, interferon responses, and innate immune sensing [1, 2, 7, 8]. Researchers study signaling adaptor activity to understand how cells convert extracellular cues into specific biological outcomes. For example, the adaptor LAT nucleates a signalosome downstream of the TCR, while MAVS forms prion-like aggregates to propagate antiviral signaling [1, 7]. STING acts as an adaptor that specifies IRF3 phosphorylation by TBK1 in the cytosolic DNA sensing pathway. These examples illustrate how adaptor proteins dictate the specificity, amplitude, and duration of signaling. Because adaptor proteins are central hubs, their dysfunction is linked to immune disorders, cancer, and neurodegeneration [1, 3, 4]. Targeting adaptor activity or the complexes they organize is an active area of therapeutic development. This article provides a research-grade overview of GO:0035591, covering its mechanism, key genes, disease relevance, and experimental methods including CRISPR-based models.
signaling adaptor activity At A Glance
| GO ID | GO:0035591 |
|---|---|
| GO term | signaling adaptor activity |
| Ontology | molecular_function |
| Synonym | signaling protein recruiting activity; signaling scaffold activity; signalling adaptor activity |
| Definition | The binding activity of a molecule that brings together two or more molecules in a signaling pathway, permitting those molecules to function in a coordinated way. Adaptor molecules themselves do not have catalytic activity. |
| Major function | Assembly of multiprotein signaling complexes and coordination of signal transduction |
| Example proteins | LAT, SLP-76, GADS, STING, MAVS, TRAF6, GABARAP |
| Disease relevance | Autoimmunity, immunodeficiency, cancer, neurodegeneration, inflammatory diseases |
What Is GO:0035591?
According to the Gene Ontology, signaling adaptor activity (GO:0035591) is the binding activity of a molecule that brings together two or more molecules in a signaling pathway, permitting those molecules to function in a coordinated way. Adaptor molecules themselves do not have catalytic activity. In other words, an adaptor acts as a molecular bridge or scaffold, using protein-protein interaction domains to assemble signaling complexes without directly catalyzing a chemical reaction.
Why Is signaling adaptor activity Important in Cell Biology?
Signaling adaptor activity is fundamental to how cells interpret and respond to their environment. By physically linking signaling molecules, adaptors ensure that signals are transmitted with high fidelity and specificity. Disruption of adaptor function can lead to severe immune deficiencies, uncontrolled inflammation, or cancer, as seen with mutations in LAT, STING, or MAVS [1, 4, 7, 8]. Understanding adaptor biology therefore provides insights into basic signal transduction and offers opportunities for therapeutic intervention.
• Adaptors are essential for T cell receptor signaling and adaptive immunity.
• They mediate innate immune responses to viral and bacterial infections through MAVS and STING [7, 8].
• Adaptor dysfunction is linked to autoinflammatory diseases and immunodeficiency [1, 8].
• They play roles in cancer progression by organizing oncogenic signaling hubs [3, 5].
• Adaptors are involved in neurodegeneration, including LRRK2 activation at lysosomes.
• They provide specificity in interferon signaling pathways.
• Adaptor proteins are attractive targets for drug discovery due to their central roles [1, 4].
• CRISPR screens can identify novel adaptor functions and interactions [1, 8].
• Understanding adaptor activity aids in designing targeted therapies for immune disorders [1, 2].
• Adaptors coordinate cross-talk between multiple signaling pathways [3, 7].
What Happens During signaling adaptor activity?
Recruitment to activated receptors
In simple terms: Adaptor proteins are called to the cell membrane after a receptor is activated.
Upon receptor activation, adaptor proteins are recruited to the plasma membrane through interactions with phosphorylated tyrosine motifs or other docking sites. For example, the adaptor LAT is phosphorylated by ZAP-70 and recruits GADS and SLP-76 to the TCR signaling complex. This recruitment is the first step in assembling a signalosome.
Assembly of multiprotein complexes
In simple terms: Adaptors act like molecular glue, bringing multiple proteins together.
Adaptors use modular interaction domains (e.g., SH2, SH3, PTB, SAM) to bind several signaling proteins simultaneously. This enables the formation of large complexes such as the TCR signalosome, where LAT, GADS, SLP-76, and PLC-gamma1 cooperate to propagate signals. Similarly, MAVS forms prion-like aggregates that serve as platforms for antiviral signaling.
Signal amplification and propagation
In simple terms: Once assembled, the complex sends signals onward, often amplifying them.
The assembled complex facilitates phosphorylation events and conformational changes that activate downstream effectors. For instance, STING acts as an adaptor that specifies IRF3 phosphorylation by TBK1 in the cytosolic DNA sensing pathway, leading to type I interferon production. This step ensures that signals are amplified and directed to appropriate cellular responses.
Termination and regulation
In simple terms: The signal is eventually turned off to prevent excessive responses.
Adaptor activity is tightly regulated by phosphorylation, ubiquitination, and degradation. For example, TRAF6 ubiquitination is critical for NF-kB activation and is reversed by deubiquitinases. Dysregulation of these termination mechanisms can lead to chronic inflammation or autoimmunity.
Key Genes Involved in GO:0035591 signaling adaptor activity
The following genes encode proteins with signaling adaptor activity or are directly involved in adaptor-mediated complexes.
| Gene | Major Role | Research Relevance |
|---|---|---|
| LAT | Transmembrane adaptor in TCR signaling | T cell development and activation |
| SLP-76 | Cytosolic adaptor in TCR and integrin signaling | Immunodeficiency and autoimmunity |
| GADS | Adaptor linking LAT to SLP-76 | T cell signaling |
| STING | Adaptor in cytosolic DNA sensing | Innate immunity and autoinflammatory diseases |
| MAVS | Mitochondrial adaptor in antiviral signaling | Antiviral innate immunity |
| TRAF6 | Adaptor E3 ubiquitin ligase in NF-kB signaling | Inflammation and cancer |
| GABARAP | Adaptor in autophagy and LRRK2 activation | Neurodegeneration |
| YAP | Transcriptional co-activator in Hippo pathway | Organ regeneration and cancer [3, 5, 6] |
| TAZ | Transcriptional co-activator in Hippo pathway | Cancer and regeneration [3, 5] |
| IRF3 | Transcription factor activated by STING/TBK1 | Antiviral response |
| TBK1 | Kinase that phosphorylates IRF3 | Innate immunity |
| ZAP-70 | Kinase that phosphorylates LAT | T cell signaling |
| PLC-gamma1 | Enzyme recruited by LAT/SLP-76 | T cell activation |
| LRRK2 | Kinase activated by STING-CASM-GABARAP | Parkinson's disease |
| KRAS | GTPase in MAPK signaling | Cancer resistance |
| SLC7A5 | Amino acid transporter in mTOR axis | Cancer metabolism |
| NF-kB | Transcription factor downstream of TRAF6 | Inflammation and immunity |
How Is signaling adaptor activity Regulated?
Signaling adaptor activity is regulated at multiple levels. Phosphorylation of adaptor proteins can create or destroy binding sites, controlling complex assembly. Ubiquitination and deubiquitination modulate the stability and interactions of adaptors such as TRAF6. In the Hippo pathway, YAP/TAZ activity is regulated by phosphorylation and localization, affecting their adaptor-like functions in transcription. Additionally, the STING-CASM-GABARAP pathway regulates LRRK2 activation at lysosomes, linking adaptor function to neurodegeneration.
signaling adaptor activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| LAT | Immunodeficiency, autoimmunity | Knockout Jurkat cells, primary T cells |
| STING | Autoinflammatory diseases, viral susceptibility | Knock-in mice, HEK293T reporter cells |
| MAVS | Antiviral immunity defects | Knockout MEFs, A549 cells |
| LRRK2 | Parkinson's disease | Knock-in iPSC-derived neurons |
| YAP/TAZ | Cancer, osteoarthritis | Knockout cancer cell lines, chondrocytes |
Signaling adaptors in cancer
Adaptor proteins can promote oncogenesis by assembling pro-survival signaling complexes. YAP/TAZ mediate resistance to KRAS inhibitors by inhibiting proapoptotic signals and activating the SLC7A5/mTOR axis. Targeting adaptor interactions may overcome drug resistance. In osteoarthritis, GA-017 attenuates disease by activating YAP/TAZ, highlighting the therapeutic potential of modulating adaptor activity.
Adaptors in immune disorders
Mutations in TCR signaling adaptors such as LAT and SLP-76 cause immunodeficiency and autoimmunity. STING gain-of-function mutations lead to autoinflammatory diseases, while loss-of-function increases susceptibility to viral infections. MAVS is essential for antiviral innate immunity, and its dysregulation can lead to impaired interferon responses.
Adaptors in neurodegeneration
The STING-CASM-GABARAP pathway activates LRRK2 at lysosomes, implicating adaptor proteins in Parkinson's disease pathogenesis. GABARAP serves as an adaptor in autophagy, and its dysfunction may contribute to protein aggregation and neuronal death.
From signaling adaptor activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of adaptor X impair T cell activation? | CRISPR knockout in Jurkat or primary T cells |
| Does a point mutation in STING alter interferon signaling? | Knock-in HEK293T cells with STING variants |
| Can overexpression of YAP drive proliferation? | Doxycycline-inducible YAP overexpression in cancer cells |
| Where does MAVS localize during viral infection? | Tagged knock-in of MAVS with GFP in A549 cells |
| Does GABARAP adaptor activity regulate LRRK2? | Knockout of GABARAP in iPSC-derived neurons |
| What is the interactome of LAT? | APEX2 or BioID tagging of LAT in T cells |
How to Study the signaling adaptor activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| CRISPR knockout screen | Gene requirement for signaling | Identify novel adaptors in immune cells |
| Phosphoproteomics | Phosphorylation changes | Map signaling downstream of adaptors |
| BioID/APEX2 | Protein-protein interactions | Define adaptor interactomes |
| Live-cell imaging | Dynamic localization | Visualize signalosome assembly |
| Co-immunoprecipitation | Complex formation | Validate adaptor interactions |
| RNA-seq | Transcriptional output | Measure pathway activation |
| Flow cytometry | Cell surface markers and viability | Assess immune cell activation |
CRISPR knockout screens
Genome-wide CRISPR knockout screens can identify adaptor proteins required for specific signaling pathways. For example, screens in T cells have uncovered regulators of TCR signaling. These screens are powerful for discovering novel adaptor functions.
Phosphoproteomics
Mass spectrometry-based phosphoproteomics can map phosphorylation events on adaptor proteins and their binding partners, revealing how adaptor activity is regulated [1, 8]. This method is useful for identifying signaling nodes downstream of STING or MAVS.
Proximity labeling
Proximity labeling techniques such as BioID or APEX2 can identify the interactome of adaptor proteins in living cells. Tagging LAT or STING with a promiscuous biotin ligase allows spatial and temporal mapping of signaling complexes [1, 8].
Live-cell imaging
Fluorescence microscopy of tagged adaptors can visualize their recruitment to receptors and complex assembly in real time. For example, GFP-tagged MAVS has been used to observe prion-like aggregation during antiviral signaling.
How CRISPR Can Be Used to Study GO:0035591 signaling adaptor activity
Knockout
CRISPR knockout of adaptor genes such as LAT or STING is used to abolish adaptor activity and assess its role in signaling. For example, LAT knockout Jurkat cells fail to activate downstream TCR signaling. Knockout models are essential for validating loss-of-function phenotypes.
Point Mutation
Point mutations can be introduced to disrupt specific binding interfaces or phosphorylation sites on adaptors. For instance, mutating key tyrosine residues in LAT prevents its interaction with GADS, allowing dissection of individual binding events. Point-mutation models are valuable for structure-function studies.
Knock-in
Knock-in of tagged or disease-associated variants of adaptors enables tracking and functional analysis. For example, knocking in GFP-tagged MAVS allows visualization of its aggregation. Knock-in of STING gain-of-function mutations can model autoinflammatory diseases.
Overexpression
Overexpression of adaptor proteins can amplify signaling and reveal gain-of-function phenotypes. For example, overexpression of YAP/TAZ promotes proliferation and drug resistance in cancer cells. Inducible overexpression systems provide temporal control.
How EDITGENE Supports signaling adaptor activity Research
Researchers studying signaling adaptor activity-related genes often need to determine whether a candidate gene is causally involved in a signaling pathway or disease. This requires precise genetic models that can knockout, mutate, tag, or overexpress the gene of interest in relevant cell types. EDITGENE provides a comprehensive suite of CRISPR services to accelerate such studies.
Contact EDITGENE today to design your custom CRISPR model for signaling adaptor activity research.
Frequently Asked Questions About signaling adaptor activity
What is signaling adaptor activity?
Signaling adaptor activity (GO:0035591) is the binding activity of a molecule that brings together two or more signaling molecules to function coordinately, without having catalytic activity itself.
What genes are involved in signaling adaptor activity?
Key genes include LAT, SLP-76, GADS, STING, MAVS, TRAF6, GABARAP, and YAP/TAZ, among others [1, 4, 7, 8].
How does signaling adaptor activity work?
Adaptors use protein interaction domains to bind multiple signaling proteins, assembling complexes that propagate signals.
What diseases are linked to signaling adaptor activity?
Dysregulated adaptor activity is linked to immunodeficiency, autoimmunity, cancer, and neurodegeneration [1, 4, 5, 8].
What is the difference between an adaptor and a scaffold protein?
Adaptors and scaffolds both bring proteins together, but adaptors typically lack catalytic activity and often have no enzymatic function, while scaffolds may also have catalytic roles.
How can I study signaling adaptor activity in the lab?
Common methods include CRISPR knockout, co-immunoprecipitation, proximity labeling, phosphoproteomics, and live-cell imaging [1, 7, 8].
What is the role of STING as an adaptor?
STING acts as an adaptor that specifies IRF3 phosphorylation by TBK1 in the cytosolic DNA sensing pathway.
How does MAVS function as an adaptor?
MAVS forms prion-like aggregates on mitochondria to activate antiviral innate immune signaling.
Can CRISPR be used to study adaptor proteins?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression are widely used to dissect adaptor function [1, 4, 8].
What services does EDITGENE offer for adaptor research?
EDITGENE provides CRISPR knockout, point mutation, knock-in, overexpression cell models, library screening, and bioinformatics services.
Conclusion
Signaling adaptor activity (GO:0035591) is a cornerstone of cellular signal transduction, enabling the assembly of multiprotein complexes that drive immune responses, growth, and survival. Dysregulation of adaptors contributes to a wide range of diseases, making them important research and therapeutic targets. Advances in CRISPR technology and functional genomics provide powerful tools to dissect adaptor biology and develop new treatments.
References
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- 2. Platanias LC. 2005. Mechanisms of type-I- and type-II-interferon-mediated signalling.. Nat Rev Immunol 5(5):375-86 PMID: 15864272
- 3. Moya IM et al.. 2019. Hippo-YAP/TAZ signalling in organ regeneration and regenerative medicine.. Nat Rev Mol Cell Biol 20(4):211-226 PMID: 30546055
- 4. Bentley-DeSousa A et al.. 2025. A STING-CASM-GABARAP pathway activates LRRK2 at lysosomes.. J Cell Biol 224(2) PMID: 39812709
- 5. Yang W et al.. 2024. YAP/TAZ mediates resistance to KRAS inhibitors through inhibiting proapoptosis and activating the SLC7A5/mTOR axis.. JCI Insight 9(24) PMID: 39704172
- 6. Li X et al.. 2025. GA-017 attenuates OA by activating YAP/TAZ.. Biochem Pharmacol 242(Pt 3):117389 PMID: 41047035
- 7. Hou F et al.. 2011. MAVS forms functional prion-like aggregates to activate and propagate antiviral innate immune response.. Cell 146(3):448-61 PMID: 21782231
- 8. Tanaka Y et al.. 2012. STING specifies IRF3 phosphorylation by TBK1 in the cytosolic DNA signaling pathway.. Sci Signal 5(214):ra20 PMID: 22394562
