Recombinant Neuronal calcium sensor 1 (ncs-1)
Description
Definition and Production
Recombinant NCS-1 is produced using heterologous expression systems (e.g., E. coli or yeast) to study its calcium-sensing properties and interactions. Unlike native NCS-1, recombinant variants allow precise manipulation for structural and functional analyses . Key features include:
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Post-translational modifications: Often lacks myristoylation in bacterial systems, affecting membrane association .
Functional Roles
Recombinant NCS-1 regulates diverse pathways:
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Calcium signaling: Modulates Ca²⁺-dependent exocytosis, ion channel activity, and kinase activation .
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Synaptic plasticity: Enhances long-term potentiation (LTP) and suppresses long-term depression (LTD) .
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Neuroprotection: Reduces hyperexcitation and Ca²⁺ overload in GABAergic neurons during ischemia .
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Disease associations: Linked to bipolar disorder, schizophrenia, and chemotherapy-induced neuropathy .
Neuroprotection Against Ischemia
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Model: Cortical neurons subjected to oxygen-glucose deprivation (OGD) showed NCS-1 knockdown (KD) increased apoptosis (57% necrosis) vs. controls .
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Mechanism: NCS-1 preserves GABAergic neuron populations, suppressing glutamate receptor overactivation .
Synaptic Regulation via Ric-8A
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Recombinant NCS-1 binds Ric-8A, blocking casein kinase II phosphorylation and inhibiting Gα nucleotide exchange .
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Structural basis: Crystal structures (PDB: 8ELI) reveal NCS-1’s hydrophobic crevice anchors Ric-8A helices .
Variant-Specific Effects
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Var1 vs. Var2: Truncated Var2 shows 100x weaker calcium affinity than Var1, with no detectable impact on cell growth or paclitaxel sensitivity .
Table 2: Functional Comparison of NCS-1 Variants
| Parameter | Var1 | Var2 |
|---|---|---|
| Calcium affinity | High () | Low () |
| Thermal stability | Stable | Reduced |
| Functional impact | Enhances Ca²⁺ signaling | No significant effect |
Therapeutic Applications
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Neurodegenerative diseases: Overexpression rescues CaMKII-α phosphorylation and BDNF levels, improving spatial memory in mice .
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Chemotherapy-induced neuropathy: NCS-1 degradation by μ-calpain contributes to taxol toxicity; recombinant NCS-1 may mitigate this .
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Psychiatric disorders: NCS-1’s interaction with D2 dopamine receptors offers targets for bipolar disorder and schizophrenia .
Challenges and Future Directions
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Variant heterogeneity: Functional differences between isoforms complicate therapeutic targeting .
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Metal interplay: Zn²⁺/Mg²⁺ competition alters calcium sensitivity, requiring precise modulation .
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Drug development: Structural insights into NCS-1/Ric-8A interactions enable rational design of synapse regulators .
Product Specs
Target Background
Q&A
What expression systems are optimal for producing functional recombinant NCS-1?
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Buffer optimization: Use 20 mM Tris-HCl (pH 8.0) with 1 mM DTT and 10% glycerol to maintain stability .
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Purity validation: SDS-PAGE (>95% purity) and BCA assays for concentration quantification .
How do researchers validate recombinant NCS-1 activity in calcium-binding assays?
Activity validation involves:
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Calcium titration: Measure conformational changes via circular dichroism (CD) spectroscopy at varying Ca²⁺ concentrations (0.1–10 μM) .
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Functional assays: Monitor NCS-1’s enhancement of P/Q-type calcium channel currents in transfected HEK293 cells using patch-clamp electrophysiology .
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Interaction studies: Surface plasmon resonance (SPR) to quantify binding kinetics with targets like PI4KB (K<sub>D</sub> ≈ 0.3 μM) .
What experimental models best recapitulate NCS-1’s role in synaptic plasticity?
How to resolve contradictions in NCS-1’s reported effects on neuronal survival?
Conflicting data arise from:
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Dose-dependent effects: Low NCS-1 enhances neuroprotection via PI4KB activation, while overexpression induces apoptosis through TRPC5 overactivation .
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Cell-type specificity: Cortical GABAergic neurons show Ca²⁺ dysregulation upon NCS-1 knockdown, unlike glutamatergic neurons .
Resolution strategy: -
Perform single-cell RNA sequencing to map NCS-1 interaction partners across neuronal subtypes .
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Use inducible knockout models to separate developmental vs. acute effects .
What strategies improve recombinant NCS-1 stability for structural studies?
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Crystallization additives: Include 0.1 M HEPES (pH 7.5), 12% PEG 3350, and 200 mM MgCl₂ to stabilize EF-hand domains .
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NMR buffer optimization: Use 50 mM Tris-d11 (pH 6.8), 100 mM NaCl, and 5 mM CaCl₂ in 90% H₂O/10% D₂O .
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Cryo-EM sample prep: Embed NCS-1 in nanodiscs with POPC lipids to mimic membrane proximity .
How to design experiments analyzing NCS-1’s role in neurodevelopmental disorders?
Stepwise approach:
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Gene editing: Create isogenic iPSC lines with NCS1 CRISPR knockouts or patient-derived mutations (e.g., R102Q linked to autism) .
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Functional phenotyping:
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Multi-omics integration: Combine RNA-Seq (e.g., differential BDNF expression ) with phosphoproteomics to map signaling cascades.
How to distinguish NCS-1’s direct vs. indirect effects in calcium signaling pathways?
What controls are essential when studying NCS-1 in disease models?
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Genetic controls: Use Ncs1<sup>+/−</sup> heterozygotes to rule out compensatory mechanisms .
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Pharmacological controls: Apply 10 μM W-7 (calmodulin inhibitor) to isolate NCS-1-specific effects .
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Cell viability metrics: Include LDH release assays alongside calcium imaging to exclude cytotoxicity .
How can single-molecule tracking advance NCS-1 research?
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Total internal reflection microscopy (TIRFM): Track NCS-1 mobility on supported lipid bilayers at 100 fps .
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Key findings:
What multi-omics approaches elucidate NCS-1’s pleiotropic functions?
What criteria confirm successful NCS-1 knockdown in neuronal cultures?
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qPCR: ≥70% reduction in NCS1 mRNA (primers: F-5′-CAGGTCAAGGAGCGGATCTAC-3′, R-5′-GCACATCGGTCTTGTTGAGG-3′) .
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Western blot: Use anti-NCS1 (Abcam ab129009) with GAPDH loading control .
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Functional rescue: Co-transfect shRNA-resistant NCS1 cDNA (e.g., pCI-NCS1<sub>mut</sub>) .
