Recombinant Pan troglodytes Interleukin-1 receptor accessory protein-like 1 (IL1RAPL1)

What is the structural composition of Pan troglodytes IL1RAPL1?

Pan troglodytes IL1RAPL1, like its human homolog, is a single-pass type I membrane protein belonging to the IL-1 receptor superfamily. Its structure consists of several key domains: an N-terminal signal peptide (approximately amino acids 1-18), three extracellular immunoglobulin-like domains (amino acids 19-350), a transmembrane domain (amino acids 358-378), an intracellular Toll/IL-1R domain (amino acids 403-562), and a C-terminal tail (amino acids 549-644) that interacts with various signaling molecules . The chimpanzee variant shares high sequence homology with the human form but contains species-specific variations that may affect protein-protein interactions and downstream signaling pathways.

How does IL1RAPL1 function in neuronal development?

IL1RAPL1 plays critical roles in neuronal development, particularly in synapse formation and maintenance. Research demonstrates that IL1RAPL1 mediates excitatory synapse formation through trans-synaptic interaction with protein tyrosine phosphatase delta (PTPδ) . In normal neural development, IL1RAPL1 expression is upregulated by neuronal activity, particularly in the postnatal hippocampus . This activity-dependent regulation suggests IL1RAPL1's importance in experience-dependent neural plasticity. Knockout studies in mice reveal that IL1RAPL1 ablation results in decreased spine density in cortical neurons, providing direct evidence for its role in synaptogenesis and spine morphology maintenance .

What evolutionary differences exist between human and Pan troglodytes IL1RAPL1?

While specific evolutionary differences in IL1RAPL1 between humans and chimpanzees have not been comprehensively documented in the provided search results, comparative genomic analyses of related mechanisms suggest potentially important differences. Research on genetic elements such as LINE-1 (L1) retrotransposons indicates differing regulatory mechanisms between humans and non-human primates that could affect gene expression patterns . These differences in genetic regulation mechanisms may extend to IL1RAPL1 expression and function, potentially contributing to species-specific neural development patterns. The evolutionary divergence between human and chimpanzee IL1RAPL1 may involve subtle sequence variations that affect protein-protein interactions, subcellular localization, or downstream signaling efficacy.

What are the optimal methods for cloning and expressing recombinant Pan troglodytes IL1RAPL1?

For successful cloning and expression of recombinant Pan troglodytes IL1RAPL1, researchers should consider adapting approaches similar to those used for other chimpanzee proteins. Drawing from the methodologies described for L1 element cloning , the process would involve:

• Genomic identification: Identify intact IL1RAPL1 gene sequences in the Pan troglodytes genome (CSAC 2.1.4/panTro4, UCSC) through Blat analyses.

• Primer design: Design primers that match unique sequences flanking the 5' and 3' ends of the IL1RAPL1 gene.

• PCR amplification: Amplify the gene using high-fidelity polymerase (such as Phusion High-Fidelity polymerase) from genomic DNA extracted from chimpanzee cells.

• Verification: Sequence the PCR product to confirm intactness and absence of mutations.

• Vector construction: Design a second PCR to introduce appropriate restriction sites, then digest and insert into an expression vector compatible with mammalian cell expression.

• Expression: Transfect the construct into an appropriate mammalian cell line (HEK293T cells are commonly used) for protein expression .

For optimal protein yield, consider codon optimization for the expression system and include a purification tag (His, FLAG, or GST) that doesn't interfere with protein folding or function.

How can researchers effectively measure IL1RAPL1 promoter activity in Pan troglodytes versus human cells?

To measure and compare IL1RAPL1 promoter activity between Pan troglodytes and human cells, researchers should adapt the dual-luciferase reporter assay methodology. Based on similar comparative studies , the following protocol is recommended:

• Amplify the IL1RAPL1 promoter region (5'UTR) from both human and chimpanzee genomic DNA using PCR.

• Clone these promoter regions into a reporter vector (such as pGL4.10) upstream of a firefly luciferase cDNA.

• Co-transfect the promoter-reporter constructs alongside a control plasmid expressing Renilla luciferase into both human and chimpanzee iPSC lines.

• After 72 hours post-transfection, quantify luciferase activity using a dual-luciferase reporter assay.

• Normalize the firefly luciferase signal to the Renilla luciferase signal to control for transfection efficiency.

• Express results relative to human IL1RAPL1 promoter activity in human cells to determine species-specific differences .

This approach allows for direct comparison of promoter strength between species and can reveal evolutionary differences in transcriptional regulation.

What are the protein-protein interaction differences between human and Pan troglodytes IL1RAPL1?

While the provided search results don't directly address protein-protein interaction differences between human and Pan troglodytes IL1RAPL1, researchers investigating this question should focus on the following methodology:

• Comparative co-immunoprecipitation (Co-IP) assays using tagged versions of human and chimpanzee IL1RAPL1 to identify differences in binding partners.

• Yeast two-hybrid screening with the intracellular domain (aa 403-644) which contains the Toll/IL-1R domain and C-terminal tail known to interact with signaling molecules .

• Proximity-dependent biotin identification (BioID) or APEX2 proximity labeling to identify the proximal proteome of each species' IL1RAPL1 variant in neuronal contexts.

• Surface plasmon resonance (SPR) or microscale thermophoresis (MST) to quantitatively compare binding affinities with known interaction partners like PTPδ .

• Structural biology approaches including cryo-EM or X-ray crystallography to resolve potential structural differences that may impact protein-protein interactions.

Expected differences might include altered binding affinities with synaptic proteins, species-specific interaction partners, or differences in downstream signaling cascade activation. These differences could contribute to species-specific aspects of neuronal development and synaptic plasticity.

How does recombinant Pan troglodytes IL1RAPL1 affect synapse formation in comparison to human IL1RAPL1?

To investigate differential effects of Pan troglodytes versus human IL1RAPL1 on synapse formation, researchers should implement the following experimental approach:

• Preparation of purified recombinant proteins: Express and purify both human and Pan troglodytes IL1RAPL1 extracellular domains (aa 19-350) with >95% purity as these domains mediate the trans-synaptic interactions .

• Primary neuronal culture system: Establish cortical or hippocampal neuron cultures from both species and from IL1RAPL1 knockout mice as a neutral background system.

• Synaptogenesis assay: Apply equivalent concentrations of each recombinant protein to cultured neurons and quantify:

  • Dendritic spine density (using fluorescent markers like DiI)

  • Presynaptic and postsynaptic marker colocalization (Synapsin-1/PSD-95)

  • Functional synapse formation using electrophysiological recordings

  • Recruitment of PTPδ to contact sites (using immunofluorescence)

• Artificial synapse formation assay: Use a heterologous cell system where non-neuronal cells expressing either human or chimpanzee IL1RAPL1 are co-cultured with neurons to induce presynaptic differentiation.

Based on studies with IL1RAPL1 knockout mice showing decreased spine density , species-specific differences might manifest as varying degrees of synaptogenic activity, potentially correlated with differences in binding affinity to trans-synaptic partners.

What molecular mechanisms underlie IL1RAPL1-related cognitive phenotypes in different species?

The molecular mechanisms underlying IL1RAPL1-related cognitive phenotypes involve multiple interrelated pathways that may show species-specific variations. Based on knockout mouse studies , these mechanisms include:

• Synaptic density regulation: IL1RAPL1 knockout mice demonstrate reduced spine density in cortical neurons, suggesting direct effects on synaptogenesis or spine maintenance . This likely contributes to impairments in spatial memory and behavioral flexibility.

• Trans-synaptic signaling: IL1RAPL1 interacts with presynaptic PTPδ to mediate excitatory synapse formation , potentially affecting synaptic specificity and strength.

• Intracellular signaling cascades: The intracellular Toll/IL-1R domain (aa 403-562) and C-terminal tail (aa 549-644) interact with downstream signaling molecules , likely triggering cascades that influence gene expression patterns important for neuronal development.

• Activity-dependent regulation: IL1RAPL1 expression is upregulated by neuronal activity particularly in the postnatal hippocampus , suggesting involvement in experience-dependent plasticity mechanisms.

• Impact on behavioral inhibition: IL1RAPL1 knockout mice show decreased anxiety-like behaviors and increased locomotor activity , suggesting roles in behavior regulation beyond direct cognitive functions.

To investigate species-specific variations in these mechanisms, researchers should employ comparative transcriptomics, proteomics, and phosphoproteomics in IL1RAPL1-manipulated neuronal systems from different species, with particular focus on synaptic protein complexes and activity-dependent signaling pathways.

What are the major technical challenges in producing functional recombinant Pan troglodytes IL1RAPL1?

Producing functional recombinant Pan troglodytes IL1RAPL1 presents several technical challenges that researchers should anticipate and address:

• Protein solubility and folding: As a transmembrane protein with multiple immunoglobulin-like domains , IL1RAPL1 may face folding challenges during recombinant expression. Researchers should consider:

  • Expression of individual domains separately

  • Inclusion of molecular chaperones during expression

  • Testing various detergents for membrane domain solubilization

  • Using insect cell or mammalian expression systems rather than bacterial systems

• Post-translational modifications: IL1RAPL1 likely requires specific glycosylation patterns for proper function. Expression systems should preserve these modifications, with mammalian cell lines (particularly those derived from neural lineages) being preferred.

• Functional verification: Confirming that recombinant IL1RAPL1 retains native activity requires specialized assays:

  • Binding assays with known partners like PTPδ

  • Cell-based assays measuring synaptogenic activity

  • Structural integrity verification via circular dichroism or thermal shift assays

• Species-specific sequence verification: Ensuring the accuracy of the Pan troglodytes IL1RAPL1 sequence requires careful genomic analysis and validation, similar to approaches used for cloning chimpanzee L1 elements .

• Expression optimization: Codon usage differences between species may necessitate optimization for the expression system used, requiring careful design of synthetic gene constructs.

How can researchers investigate the evolutionary divergence of IL1RAPL1 function across primate species?

To comprehensively investigate evolutionary divergence of IL1RAPL1 across primates, researchers should implement a multi-faceted approach:

• Comparative genomics and phylogenetic analysis:

  • Sequence IL1RAPL1 genes from multiple primate species

  • Calculate selection pressures (dN/dS ratios) across different domains

  • Identify rapidly evolving residues that may indicate functional adaptation

  • Map changes onto structural models to predict functional impacts

• Cross-species functional assays:

  • Generate recombinant IL1RAPL1 proteins from multiple primate species

  • Compare binding affinities to conserved partners like PTPδ

  • Assess synaptogenic activity in standardized neuronal cultures

  • Perform domain swapping experiments to pinpoint functionally divergent regions

• iPSC-based comparative models:

  • Derive induced pluripotent stem cells from different primate species

  • Differentiate into neurons with comparable protocols

  • Analyze IL1RAPL1 expression, localization, and function

  • Perform IL1RAPL1 knockdown/rescue experiments with cross-species variants

• Molecular clock analyses:

  • Estimate divergence times for IL1RAPL1 functional changes

  • Correlate with known events in primate brain evolution

  • Compare with other synaptic genes to identify co-evolutionary patterns

This approach would build upon observed differences in genetic regulation between human and non-human primates and provide insights into how synaptic protein divergence may have contributed to species-specific cognitive adaptations.

Table: Comparative Analysis of IL1RAPL1 Structure and Function Across Species

Note: Where direct experimental data for Pan troglodytes IL1RAPL1 is limited, predictions are based on high sequence conservation and evolutionary proximity .

What methodological approaches are most effective for comparative IL1RAPL1 functional studies across species?

For robust comparative studies of IL1RAPL1 function across species, researchers should implement a methodological framework that controls for species-specific variables while enabling direct functional comparison:

• Standardized expression systems:

  • Use identical promoters for expression studies rather than native promoters

  • Employ the same cell background for all species variants (e.g., IL1RAPL1-knockout mouse neurons)

  • Ensure equivalent protein expression levels through quantitative western blotting

• Domain-specific functional analysis:

  • Test individual domains separately (extracellular, transmembrane, intracellular)

  • Create chimeric proteins with domains from different species

  • Use quantitative binding assays with recombinant protein fragments

• Controlled neuronal assays:

  • Develop standardized primary culture conditions

  • Use equivalent developmental timepoints for analysis

  • Employ automated, unbiased image analysis for morphological studies

• iPSC-derived neuronal models:

  • Generate iPSCs from different species following identical reprogramming protocols

  • Differentiate using standardized methods to minimize protocol-based variation

  • Perform parallel genetic manipulations (CRISPR knockin/knockout)

• Data normalization approaches:

  • Always include within-species controls

  • Report relative changes rather than absolute values when comparing across species

  • Use multiple independent methodologies to confirm findings

This methodological framework builds upon approaches used in comparative studies of L1 regulation in pluripotent stem cells , adapting them specifically for IL1RAPL1 functional analysis across primate species.

How might targeting IL1RAPL1 pathways inform cross-species models of neurodevelopmental disorders?

The study of IL1RAPL1 across species offers valuable insights for neurodevelopmental disorder modeling, particularly given its association with nonsyndromic intellectual disability and autism in humans . To effectively leverage this for cross-species disease modeling:

• Comparative neural circuitry analysis:

  • Map IL1RAPL1 expression patterns across homologous brain regions in multiple species

  • Identify species-specific versus conserved aspects of IL1RAPL1 function

  • Determine which aspects of human neurodevelopmental disorders can be modeled in other species

• Precision disease modeling:

  • Introduce human disease-associated IL1RAPL1 variants into chimpanzee cells

  • Compare with the same variants in human cells

  • Identify species-specific compensatory mechanisms that may explain phenotypic differences

• Therapeutic target validation:

  • Test whether compounds targeting IL1RAPL1 pathways have consistent effects across species

  • Identify conserved downstream targets that may be more amenable to therapeutic intervention

  • Develop assays that predict human-specific responses to potential therapeutics

• Evolutionary neurobiology insights:

  • Correlate species differences in IL1RAPL1 function with known cognitive and behavioral differences

  • Examine how IL1RAPL1 interacts with species-specific aspects of brain development

  • Identify convergent versus divergent aspects of synaptic development across lineages

This approach would build upon findings from IL1RAPL1 knockout mice while addressing the limitations of single-species models for complex human neurodevelopmental disorders.

What emerging technologies could advance Pan troglodytes IL1RAPL1 research beyond current methodological limitations?

Several emerging technologies show particular promise for advancing Pan troglodytes IL1RAPL1 research:

• Single-cell multi-omics:

  • Single-cell RNA-seq combined with ATAC-seq to correlate IL1RAPL1 expression with chromatin accessibility

  • Spatial transcriptomics to map IL1RAPL1 expression patterns in intact tissue with cellular resolution

  • Single-cell proteomics to identify cell type-specific IL1RAPL1 interactomes

• Advanced genome editing:

  • Prime editing for precise introduction of species-specific IL1RAPL1 variants

  • Base editing for testing specific amino acid substitutions

  • Inducible CRISPR systems for temporal control of IL1RAPL1 manipulation

• Organoid technologies:

  • Brain region-specific organoids from multiple primate species

  • Assembloids combining different brain regions to study circuit development

  • Long-term organoid cultures to assess developmental trajectories

• Advanced imaging techniques:

  • Super-resolution microscopy for nanoscale IL1RAPL1 localization

  • Expansion microscopy for detailed synaptic architecture analysis

  • Light-sheet microscopy for whole-organoid IL1RAPL1 function visualization

• Computational approaches:

  • AlphaFold and related AI tools for predicting species-specific structural differences

  • Network analysis tools to predict differential impacts on signaling pathways

  • Evolutionary simulation to model selective pressures on IL1RAPL1

These technologies would enable researchers to move beyond the current limitations of comparative IL1RAPL1 studies, addressing questions about its role in primate brain evolution and neurodevelopmental disorders that cannot be answered with conventional approaches.