GO:0005047 signal recognition particle binding: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0005047 signal recognition particle binding is a molecular function describing binding to a signal recognition particle (SRP), the ribonucleoprotein complex that targets nascent secretory and membrane proteins to the endoplasmic reticulum.
• The classical SRP receptor (SR) is a heterodimeric GTPase (SR alpha/SR beta in eukaryotes) that docks the SRP-ribosome-nascent chain complex at the ER membrane.
• Recent work identified a release factor that accelerates substrate release from SRP after membrane delivery, adding a new step to the canonical targeting cycle.
• SRP abundance and activity are temporally regulated during translation and respond globally to acute thermal stress, linking SRP binding to proteostasis.
• SRP components are conserved from bacteria to humans, with vestigial SRP-based targeting still detectable in mitochondria.
• Dysregulation of SRP-dependent targeting is implicated in cancer, neurodegeneration and secretory pathway disorders, making GO:0005047 a tractable target for CRISPR models.
Description
GO:0005047 signal recognition particle binding is the molecular function of physically associating with a signal recognition particle (SRP), the conserved ribonucleoprotein that recognizes signal sequences on nascent polypeptides and delivers them to the endoplasmic reticulum (ER) membrane. This binding event is the central recognition step of co-translational protein targeting and is required for the biogenesis of secretory proteins, plasma membrane proteins and many organellar proteins. Researchers study GO:0005047 because it defines the molecular interface between the SRP and its receptor, a GTP-dependent docking reaction that determines the fidelity and efficiency of protein targeting. The function is not limited to the canonical SRP receptor: additional factors that modulate SRP-substrate interactions have recently been identified, expanding the set of proteins annotated to this term. Because SRP binding is coupled to translation and to cellular stress responses, it sits at the intersection of protein synthesis, membrane biology and proteostasis. Understanding GO:0005047 therefore provides mechanistic insight into how cells partition proteins between the cytosol and the secretory pathway, and how this partitioning fails in disease.
signal recognition particle binding At A Glance
| GO ID | GO:0005047 |
|---|---|
| GO term | signal recognition particle binding |
| Ontology | molecular_function |
| Synonym | docking protein; signal recognition particle receptor |
| Definition | Binding to a signal recognition particle. |
| Major function | Docking of the SRP-ribosome-nascent chain complex at the ER membrane and regulation of substrate release |
| Representative gene products | SR alpha (SRPRA), SR beta (SRPRB), and accessory release factors |
| Conservation | Present from bacteria to humans, with vestigial SRP-based targeting in mitochondria |
| Related processes | Co-translational protein targeting, ER translocation, proteostasis under thermal stress |
What Is GO:0005047?
In the Gene Ontology, GO:0005047 signal recognition particle binding is defined as binding to a signal recognition particle. It is a molecular_function term, meaning it describes what a gene product does at the molecular level rather than a whole pathway or cellular location. The term covers any protein or RNA that directly associates with the SRP complex, including the canonical SRP receptor (docking protein) and accessory factors that regulate SRP-substrate release. Synonyms for this term include docking protein and signal recognition particle receptor, reflecting the historical identification of the SRP receptor as the membrane-bound binding partner of SRP.
Why Is signal recognition particle binding Important in Cell Biology?
GO:0005047 signal recognition particle binding is important because it governs the first committed step of co-translational protein targeting, determining whether a nascent secretory or membrane protein is delivered to the ER or mislocalized in the cytosol. The reaction is GTP-dependent and conformationally coupled to signal-sequence recognition, so its regulation directly affects protein biogenesis capacity. Recent studies show that SRP binding is temporally regulated during translation and that SRP orchestrates a global cellular response to acute thermal stress, linking this molecular function to stress adaptation and proteome maintenance. Because SRP components are conserved and essential, mutations or expression changes in SRP-binding proteins can disrupt secretory pathway homeostasis and contribute to disease.
• Defines the molecular recognition step that commits nascent secretory and membrane proteins to the ER.
• Controls the fidelity of signal-sequence decoding and prevents mistargeting of cytosolic proteins.
• Is GTP-dependent, making it a regulatory node for energy-coupled protein targeting.
• Is temporally regulated during translation, coupling targeting to the rate of protein synthesis.
• Participates in a global cellular response to acute thermal stress, linking SRP binding to proteostasis.
• Is conserved across evolution, with vestigial SRP-based targeting in mitochondria.
• Provides a mechanistic explanation for secretory pathway disorders and ribosomopathies.
• Offers a target for CRISPR knockout, point-mutation and knock-in models to dissect targeting mechanisms.
Molecular Mechanism of signal recognition particle binding
Signal-sequence recognition and SRP engagement
In simple terms: The SRP first grabs a newly made protein's signal sequence, and this binding is what the GO term describes.
During translation, the SRP binds the hydrophobic signal sequence of a nascent polypeptide as it emerges from the ribosome. Signal-sequence binding induces conformational changes in the SRP that prime it for receptor interaction. This step is the molecular basis of GO:0005047 because it establishes the SRP-substrate complex that will subsequently bind the SRP receptor.
Docking at the SRP receptor
In simple terms: The SRP then docks onto its receptor on the ER membrane, like a ship mooring at a dock.
The canonical SRP receptor is a heterodimeric GTPase composed of SR alpha and SR beta subunits in eukaryotes. Binding of the SRP-ribosome-nascent chain complex to the receptor occurs at the ER membrane and is coupled to GTP binding by both partners. This docking reaction is the defining molecular function annotated as GO:0005047, and its disruption prevents efficient protein translocation.
GTP-dependent conformational cycling
In simple terms: Both the SRP and its receptor use GTP as a switch to change shape and let go at the right time.
The SRP and SRP receptor are both GTPases, and their interaction is regulated by reciprocal GTP-dependent conformational changes. Signal-sequence-induced conformational changes in the SRP are transmitted to the receptor, driving a cycle that culminates in substrate handover to the translocon. This GTPase cycle ensures that binding is transient and productive rather than stable and non-productive.
Substrate release and recycling
In simple terms: After delivery, a helper factor helps the SRP let go of its cargo so the cycle can start again.
A recently identified factor accelerates substrate release from the SRP, adding a dedicated release step to the targeting cycle. This release factor acts after membrane delivery to promote dissociation of the SRP from its substrate, allowing the SRP to be recycled for subsequent rounds of targeting. This finding expands the set of proteins that functionally interact with the SRP and refines our understanding of GO:0005047.
Temporal and stress-responsive regulation
In simple terms: The cell adjusts how much SRP binding happens depending on translation rate and stress.
SRP activity is temporally regulated during translation, so that targeting capacity is matched to the flux of nascent chains. In addition, 7SL RNA and the SRP orchestrate a global cellular response to acute thermal stress, indicating that SRP binding is integrated into stress-responsive proteostasis networks. These layers of regulation mean that GO:0005047 is not a static binding event but a dynamically controlled molecular function.
Key Genes Involved in GO:0005047 signal recognition particle binding
The following genes and gene products are experimentally linked to signal recognition particle binding (GO:0005047) or to the SRP-dependent targeting cycle it governs.
| Gene | Major Role | Research Relevance |
|---|---|---|
| SRPRA | SR alpha subunit of the SRP receptor; docks SRP at the ER membrane | Core GO:0005047 gene; knockout disrupts co-translational targeting |
| SRPRB | SR beta subunit of the SRP receptor; GTPase partner of SR alpha | Required for efficient SRP docking and GTP-dependent cycling |
| SRP54 | Signal-sequence-binding subunit of the SRP | Defines the SRP side of the GO:0005047 interaction |
| SRP19 | SRP assembly factor that binds SRP RNA | Required for SRP biogenesis and subsequent receptor binding |
| SRP68 | SRP subunit involved in signal-sequence recognition | Contributes to SRP function and targeting fidelity |
| SRP72 | SRP subunit implicated in SRP assembly and stability | Loss impairs SRP-dependent targeting |
| 7SL RNA | RNA scaffold of the SRP | Essential for SRP structure and stress-responsive function |
| GET3 | Tail-anchored protein targeting factor with SRP-like chaperone activity | Comparative model for SRP-independent targeting |
| SRP receptor-like mitochondrial proteins | Vestigial SRP-based targeting in mitochondria | Evolutionary context for GO:0005047 |
| Apostichopus japonicus SRP receptor | SRP receptor homolog in sea cucumber | Comparative and evolutionary studies of SRP binding |
| Release factor for SRP substrate | Accelerates substrate release from SRP | Newly identified regulator of GO:0005047 |
| Translocon subunits (SEC61A1 etc.) | Receive substrates after SRP release | Downstream partners of SRP binding |
| Ribosome-associated chaperones | Coordinate nascent chain handling with SRP | Modulate targeting efficiency |
| Thermal stress response factors | Interact with SRP under heat shock | Link GO:0005047 to stress proteostasis |
| GTPase regulators | Control nucleotide state of SRP and receptor | Regulate the docking cycle |
| SRP RNA-binding proteins | Stabilize SRP RNA scaffold | Affect SRP assembly and function |
How Is signal recognition particle binding Regulated?
Signal recognition particle binding is regulated at multiple levels. The SRP and its receptor are GTPases, so their interaction is controlled by nucleotide-dependent conformational cycling and by signal-sequence-induced structural changes. SRP activity is also temporally regulated during translation, matching targeting capacity to the rate of nascent chain production. Under acute thermal stress, 7SL RNA and the SRP orchestrate a global cellular response, indicating that SRP binding is integrated into stress-responsive proteostasis programs. Finally, a dedicated release factor accelerates substrate release from the SRP, providing a regulatory step that terminates binding and enables recycling.
signal recognition particle binding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| SRPRA | Secretory pathway dysfunction and cancer cell growth | CRISPR knockout in cancer cell lines |
| SRPRB | Impaired ER targeting and proteostasis | Point-mutation knock-in of GTPase mutants |
| SRP54 | Signal-sequence recognition defects | Knockout and rescue with tagged SRP54 |
| 7SL RNA | Thermal stress response and proteostasis | CRISPR interference or RNA depletion |
| SRP19 | SRP assembly and ribosomopathy-like phenotypes | Knockout with SRP RNA reporter |
Cancer and secretory pathway rewiring
Tumors frequently rewire secretory pathway capacity to support proliferation and invasion. Because GO:0005047 controls delivery of secretory and membrane proteins to the ER, altered SRP binding can change the surface proteome and secreted factors that drive tumor growth. Experimental disruption of SRP receptor function is therefore used to probe how targeting fidelity contributes to oncogenic phenotypes.
Neurodegeneration and proteostasis
Neurons are highly dependent on efficient protein targeting and quality control. SRP-dependent targeting is coupled to proteostasis networks, and SRP orchestrates a global response to acute thermal stress, a condition relevant to protein-misfolding diseases. Defects in SRP binding may therefore sensitize neurons to proteotoxic stress and contribute to neurodegeneration.
Ribosomopathies and secretory disorders
Mutations affecting SRP components or SRP RNA impair co-translational targeting and can manifest as ribosomopathy-like or secretory pathway disorders. Because GO:0005047 is the molecular recognition step of targeting, its dysfunction provides a direct mechanistic link between SRP biology and these diseases.
From signal recognition particle binding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Is SRPRA required for co-translational targeting? | CRISPR knockout of SRPRA with ER-targeting reporter |
| How do GTPase mutations affect SRP docking? | Point-mutation knock-in of SRPRA/SRPRB GTPase mutants |
| Where does the SRP receptor localize during targeting? | Tagged knock-in of SRPRA with fluorescent tag |
| Does SRP overexpression alter secretory capacity? | Overexpression of SRP subunits and 7SL RNA |
| Which genes buffer SRP loss? | Genome-wide CRISPR library screening |
| How does thermal stress change SRP binding? | Heat-shock time course with SRP interactome profiling |
How to Study the signal recognition particle binding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Ribo-seq | Ribosome occupancy and translation efficiency | Assess targeting defects after SRP perturbation |
| Affinity proteomics | SRP interaction partners | Discover regulators of GO:0005047 |
| Live-cell imaging | SRP receptor localization and docking | Visualize ER targeting in tagged knock-in cells |
| GTPase assay | Nucleotide hydrolysis by SRP and receptor | Test point-mutation effects on docking |
| RNA-seq | Transcriptional response to SRP loss | Identify stress and proteostasis pathways |
| CRISPR library screening | Genes that buffer or enhance SRP loss | Find synthetic lethal interactions |
| Subcellular fractionation | Distribution of secretory proteins | Measure targeting fidelity |
| Thermal shift assay | SRP stability under heat stress | Study stress-responsive SRP function |
Ribosome profiling and translation profiling
Ribo-seq measures ribosome occupancy and can reveal changes in co-translational targeting when SRP binding is perturbed. Combining Ribo-seq with SRP depletion identifies transcripts whose targeting depends on GO:0005047.
Proteomics and interactome mapping
Affinity purification of SRP components followed by mass spectrometry identifies binding partners annotated to GO:0005047, including the newly described release factor. Quantitative proteomics of membrane and cytosolic fractions measures targeting fidelity.
Imaging of ER targeting
Fluorescent tagging of SRP subunits and the SRP receptor enables live-cell imaging of docking events at the ER membrane. Tagged knock-in models allow tracking of endogenous complexes.
Biochemical GTPase assays
GTP hydrolysis and nucleotide-binding assays reconstitute the SRP-receptor cycle in vitro and test the effect of point mutations. These assays directly measure the molecular function of GO:0005047.
How CRISPR Can Be Used to Study GO:0005047 signal recognition particle binding
Knockout
CRISPR knockout of SRPRA, SRPRB or SRP subunit genes abolishes signal recognition particle binding and causes mislocalization of secretory proteins. Knockout cell lines are used to define which transcripts depend on GO:0005047 and to identify compensatory pathways.
Point Mutation
Point-mutation knock-in of GTPase-domain residues in SRPRA or SRPRB dissects the nucleotide-dependent steps of SRP docking without eliminating protein expression. Such models separate binding from downstream translocation.
Knock-in
Tagged knock-in of SRP subunits or the SRP receptor enables imaging and interactome studies of endogenous complexes. Knock-in of reporter secretory proteins provides a readout of targeting efficiency.
Overexpression
Overexpression of SRP components or 7SL RNA tests whether increased SRP binding capacity enhances secretory pathway output or protects against stress. Overexpression models are also used to study dominant effects of SRP mutants.
How EDITGENE Supports signal recognition particle binding Research
Researchers studying signal recognition particle binding-related genes often need to determine whether a candidate gene is causally involved in SRP-dependent targeting or is merely correlated with it. CRISPR-based models provide the causal test: knockout, point mutation, knock-in and overexpression let you move from association to mechanism. EDITGENE supports this workflow with validated cell model engineering and screening services tailored to GO:0005047 biology.
Contact EDITGENE today to design your custom CRISPR model for signal recognition particle binding research.
Frequently Asked Questions About signal recognition particle binding
What is GO:0005047 signal recognition particle binding?
GO:0005047 is a Gene Ontology molecular_function term defined as binding to a signal recognition particle (SRP), the ribonucleoprotein that targets nascent secretory proteins to the ER.
What genes are involved in signal recognition particle binding?
Key genes include SRPRA and SRPRB (SRP receptor subunits), SRP54, SRP19, SRP68, SRP72 and the 7SL RNA scaffold, as well as newly identified release factors.
What is the function of the signal recognition particle receptor?
The SRP receptor is a heterodimeric GTPase that docks the SRP-ribosome-nascent chain complex at the ER membrane, a reaction annotated as GO:0005047.
How is signal recognition particle binding regulated?
It is regulated by GTP-dependent conformational cycling, by temporal control during translation, by a dedicated substrate release factor, and by stress-responsive programs.
Why is signal recognition particle binding important for disease?
Disruption of SRP binding impairs secretory protein targeting and proteostasis, contributing to cancer, neurodegeneration and ribosomopathy-like disorders.
Which methods study signal recognition particle binding?
Ribo-seq, affinity proteomics, live-cell imaging, GTPase assays and CRISPR screens are commonly used to study GO:0005047.
Is the SRP conserved across species?
Yes, SRP-based targeting is conserved from bacteria to humans, with vestigial SRP components still detectable in mitochondria.
What happens when SRP binding is lost?
Loss of SRP binding causes mislocalization of secretory and membrane proteins and triggers compensatory stress responses.
Can CRISPR be used to study GO:0005047?
Yes, CRISPR knockout, point mutation, knock-in and overexpression models are used to test the causal role of SRP-binding genes.
What is the difference between SRP and SRP receptor?
The SRP recognizes signal sequences on nascent chains, while the SRP receptor is the membrane-bound docking protein that binds the SRP, defining GO:0005047.
Conclusion
GO:0005047 signal recognition particle binding captures the molecular recognition step at the heart of co-translational protein targeting. It is executed by the SRP receptor and its partners, regulated by GTP-dependent conformational cycling, temporal translation control and stress-responsive programs, and modulated by a newly identified substrate release factor. Because this function determines whether secretory and membrane proteins reach the ER, its dysfunction is linked to cancer, neurodegeneration and secretory pathway disorders. CRISPR-based knockout, point-mutation, knock-in and overexpression models, combined with Ribo-seq, proteomics and imaging, provide the tools needed to dissect GO:0005047 in health and disease.
References
- 1. Wang H et al.. 2024. Identification of a factor that accelerates substrate release from the signal recognition particle.. Science 386(6725):996-1003 PMID: 39607913
- 2. Qian R et al.. 2025. Temporal Regulation of Signal Recognition Particle During Translation.. J Mol Biol 437(24):169482 PMID: 41075971
- 3. Bujisic B et al.. 2025. 7SL RNA and signal recognition particle orchestrate a global cellular response to acute thermal stress.. Nat Commun 16(1):1630 PMID: 39952919
- 4. Zhang J et al.. 2023. A signal recognition particle receptor gene from the sea cucumber, Apostichopus japonicas.. Sci Rep 13(1):22973 PMID: 38151522
- 5. Pyrih J et al.. 2021. Vestiges of the Bacterial Signal Recognition Particle-Based Protein Targeting in Mitochondria.. Mol Biol Evol 38(8):3170-3187 PMID: 33837778
- 6. Moll RG. 2004. The archaeal signal recognition particle: steps toward membrane binding.. J Bioenerg Biomembr 36(1):47-53 PMID: 15168609
- 7. Leung E et al.. 2010. Biogenesis of the signal recognition particle.. Biochem Soc Trans 38(4):1093-8 PMID: 20659010
- 8. Hainzl T et al.. 2015. Signal-sequence induced conformational changes in the signal recognition particle.. Nat Commun 6:7163 PMID: 26051119
