AtaGenix Delivers Custom RMP and IKKβ Protein Expression Services for Naval Medical University’s Sepsis Research

Study Context

Sepsis, a life-threatening systemic inflammatory response to infection, claims over 14 million lives annually. A 2025 study published in Cell Communication and Signaling (DOI: 10.1186/s12964-025-02278-w) by researchers at Naval Medical University identified RNA polymerase II subunit 5-mediating protein (RMP) as a key regulator of innate immunity in macrophages. The study revealed that RMP inhibits Toll-like receptor 4 (TLR4)-induced NF-κB signaling by binding to IκB kinase β (IKKβ) and recruiting protein phosphatase 2A (PP2A), thus limiting excessive inflammation during sepsis. This mechanism offers a potential therapeutic target for mitigating sepsis-related damage.

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Client Requirements

The research team, led by Shu-jie Pang and colleagues at Naval Medical University, required high-purity RMP and IKKβ proteins for in vitro studies to investigate their interactions via surface plasmon resonance (SPR), GST-pulldown, and ADP-Glo kinase assays. AtaGenix Laboratories Co., Ltd. (Wuhan, China) was tasked with providing custom protein expression and purification services for GST, GST-mouse RMP-WT, GST-mouse RMP-S439A, and His-mouse IKKβ, ensuring compatibility with Western blot (WB) validation and functional assays.

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Technical Challenges

1. Protein Purity: Achieving high-purity proteins to ensure accurate SPR and GST-pulldown assay results.
2. Functional Integrity: Preserving the structural and functional properties of RMP and IKKβ for reliable kinase and binding studies.
3. Mutant Protein Expression: Producing the RMP-S439A mutant with consistent quality to study its enhanced binding to IKKβ.

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Custom Protein Solution

AtaGenix collaborated with the Naval Medical University research team to provide custom protein expression services for their sepsis study published in Cell Communication and Signaling (DOI: 10.1186/s12964-025-02278-w). Our solution included:

1. Protein Expression and Purification:
- Expressed GST, GST-mouse RMP-WT, GST-mouse RMP-S439A, and His-mouse IKKβ using an optimized E. coli expression system.
- Purified proteins to high purity, ensuring suitability for SPR (OpenSPR system), GST-pulldown, and ADP-Glo kinase assays.

2. Validation and Support:
- Validated protein functionality through WB assays, confirming protein integrity and specific interactions.
- Provided technical expertise to optimize protein performance in SPR and GST-pulldown assays, enabling precise analysis of RMP–IKKβ and RMP–PP2Ab interactions.

The high-purity proteins enabled the research team to confirm RMP’s inhibitory role on IKKβ via PP2A recruitment, with the RMP-S439A mutant showing enhanced binding to IKKβ. Validated through WB, the proteins supported the study’s findings, advancing the understanding of RMP as a therapeutic target for sepsis.

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