What Is GBP1? Gene, Structure, and Protein Family

Guanylate-Binding Protein 1 (GBP1) is a member of the dynamin superfamily of large GTPases. In humans, the GBP1 gene is located on chromosome 1p22.2 and encodes a ~67 kDa protein. GBP1 belongs to a family of seven human GBPs (GBP1–7), all of which are characterized by their ability to hydrolyze GTP to both GDP and GMP, a feature that distinguishes them from most other GTPases.

Structurally, GBP1 consists of a globular N-terminal GTPase domain connected by a middle domain to an elongated helical C-terminal domain. The C-terminal domain contains a CaaX prenylation motif that allows farnesylation or geranylgeranylation, enabling membrane and vesicle targeting. This structural architecture underpins GBP1's ability to oligomerize and localize to pathogen-containing vacuoles and lipid droplets inside host cells.

Recombinant Human GBP1 Protein produced for research use replicates the full-length or defined domain structure of native GBP1, enabling scientists to study its enzymatic activity, protein–protein interactions, and downstream signaling in controlled in vitro settings.

Biological Functions: Interferon Signaling and Innate Immunity

GBP1 is one of the most strongly and rapidly induced genes following stimulation with interferon-gamma (IFN-γ), making it a canonical interferon-stimulated gene (ISG). Upon IFN-γ signaling through the JAK-STAT pathway, GBP1 expression is dramatically upregulated in a wide variety of cell types including macrophages, epithelial cells, and endothelial cells.

Once expressed, GBP1 exerts its innate immune functions through several mechanisms:

• Pathogen vacuole disruption: GBP1 is recruited to the parasitophorous vacuole membrane (PVM) of intracellular pathogens such as Toxoplasma gondii and various bacteria, where it contributes to vacuole rupture and pathogen clearance.
• Inflammasome activation: GBP1 facilitates the assembly and activation of the NLRP3 and caspase-4/5/11 inflammasomes, promoting pyroptosis and IL-1β/IL-18 secretion as part of the inflammatory response.
• Antiviral defense: GBP1 has been implicated in restricting replication of several RNA and DNA viruses, in part by interfering with viral particle assembly.
• Autophagy regulation: GBP1 can promote selective autophagy of intracellular bacteria, contributing to xenophagy pathways.

These pleiotropic functions make GBP1 a central node in IFN-γ-driven host defense and a compelling target for studies of infection, inflammation, and immune evasion.

Research Applications of Recombinant Human GBP1 Protein

Recombinant Human GBP1 Protein (SKU: rp365215) is a versatile tool for multiple in vitro and biochemical research workflows:

• GTPase activity assays: Measure GTP hydrolysis kinetics and evaluate the effect of small-molecule modulators on GBP1 enzymatic function using recombinant protein as a defined substrate.
• Protein–protein interaction studies: Use recombinant GBP1 in pull-down assays, co-immunoprecipitation controls, or surface plasmon resonance (SPR) to map its interactions with NLRP3, caspase-4, and pathogen-derived effectors.
• ELISA and antibody validation: Serve as a positive control antigen for sandwich ELISA development or to validate anti-GBP1 antibody specificity by Western blot and dot blot.
• Structural and biophysical studies: Support crystallography, cryo-EM, and analytical ultracentrifugation experiments aimed at understanding GBP1 oligomerization and domain dynamics.
• Inflammasome reconstitution assays: Incorporate recombinant GBP1 into cell-free inflammasome assembly systems to dissect its scaffolding role.
• Drug discovery: Screen compound libraries for inhibitors of GBP1 GTPase activity relevant to inflammatory disease and infectious disease therapeutic programs.

The availability of a well-characterized recombinant form eliminates variability associated with cell-lysate-derived material and enables reproducible quantitative experiments.

Handling, Storage, and Quality Considerations

To maintain the biological activity and integrity of Recombinant Human GBP1 Protein, the following general best practices apply:

• Storage temperature: Store lyophilized protein at –20 °C or –80 °C; once reconstituted, aliquot immediately to avoid repeated freeze-thaw cycles. Refer to the product datasheet for the specific formulation and recommended storage buffer.
• Reconstitution: Reconstitute with sterile deionized water or the recommended buffer as specified on the Certificate of Analysis (CoA). Allow the vial to equilibrate to room temperature before opening.
• Working concentration: Determine the optimal working concentration empirically for each assay type. Start with the range suggested in the product datasheet.
• Carrier protein: If protein stability is a concern at low concentrations, consider adding BSA (0.1%) as a carrier protein, unless it interferes with downstream assay readouts.
• Purity and endotoxin: For cell-based assays and inflammasome studies, verify endotoxin levels (typically reported in EU/µg on the CoA) to avoid confounding LPS-driven innate immune responses.
• Quality documentation: Each lot should be accompanied by a CoA reporting purity (typically assessed by SDS-PAGE or HPLC), biological activity, and endotoxin levels. Contact Aladdin Scientific technical support for lot-specific documentation.

GBP1 in Disease Research: Emerging Therapeutic Relevance

Beyond its canonical role in antimicrobial immunity, GBP1 has attracted growing attention in the context of several human diseases:

• Cancer: GBP1 expression has been reported to be dysregulated in multiple tumor types. In some contexts it functions as a tumor suppressor by promoting pyroptosis of cancer cells, while in others elevated GBP1 has been associated with poor prognosis, potentially through its role in modulating the tumor immune microenvironment.
• Inflammatory and autoimmune diseases: Because GBP1 amplifies IFN-γ-driven inflammation and inflammasome activation, it is implicated in conditions such as systemic lupus erythematosus (SLE), inflammatory bowel disease (IBD), and sepsis pathophysiology.
• Infectious diseases: GBP1's well-documented restriction of intracellular pathogens including Toxoplasma gondii, Salmonella spp., and various viruses positions it as both a biomarker of IFN-γ pathway activation and a potential therapeutic target.
• Neurological disorders: Emerging evidence suggests roles for GBP1 in neuroinflammation, with potential relevance to conditions including multiple sclerosis and traumatic brain injury.

Recombinant Human GBP1 Protein supports translational research by enabling mechanistic dissection of these disease-relevant pathways in cell-free and cell-based model systems.