Keap1-Nrf2 PPI-IN-2

Reverse transcription technology uses RNA as a template to synthesize DNA. RT-PCR is simple, specific and sensitive, and can be used to detect gene expression levels and expression differences in cells; detect RNA virus content; clone cDNA sequences of specific genes.

Cytoplasmic-nuclear fractionated protein extraction separates soluble cytoplasmic proteins from nuclear-enriched proteins by mild plasma-membrane permeabilization, differential centrifugation, washing of nuclei, and extraction of nuclear proteins for downstream immunoblotting or related molecular analysis. The readout is the relative abundance of a protein in cytoplasmic and nuclear fractions, commonly assessed by western blotting together with compartment markers such as tubulin or pyruvate kinase for cytoplasm and lamin, nucleoporin, hnRNP, H2AX, or Lamin B for nuclear fractions.

By lysing cells, releasing RNA, and removing impurities such as proteins and DNA, high-purity RNA products are finally obtained. The commonly used traditional method is the guanidine isothiocyanate/phenol/chloroform method (Trizol), which is suitable for a variety of animal materials including animal tissues, microorganisms, cultured cells, etc., and most plant materials.

The pull-down assay is an in vitro technique used to detect physical interactions between two or more proteins and an invaluable tool for confirming a predicted protein-protein interaction or identifying novel interacting partners. This method typically involves the use of affinity purification with various wash and elution steps.

Immunoprecipitation (IP) is an experimental method that uses the principle of antibody specific binding to purify and enrich target proteins.

ROS/oxidative-stress fluorescent staining uses cell-permeant fluorogenic probes that become fluorescent after oxidation inside cells or tissues; commonly used examples include DCFH-DA/DCFDA for broad cellular oxidant detection, DHE for superoxide-related signal detection, MitoSOX for mitochondrial superoxide-related signal detection, and CellROX probes for oxidative-stress-associated fluorescence readouts. The assay detects probe oxidation rather than a single ROS species unless the probe and analysis method have been chemically validated for that species. DCFH-DA enters cells, is deacetylated by intracellular esterases to DCFH, and produces fluorescent DCF after oxidation, so the readout is used as an operational measure of total cellular oxidative stress rather than a species-specific ROS measurement. DHE and MitoSOX can report superoxide-related oxidation, but red fluorescence alone can include non-specific ethidium-like oxidation products; HPLC or optimized spectral approaches are

The TPA (12-O-tetradecanoylphorbol-13-acetate) and croton oil-induced mouse ear edema model is a well-established acute cutaneous inflammation system used to evaluate topical anti-inflammatory activity by measuring edema formation, neutrophil infiltration, vascular permeability, and cytokine-mediated skin responses in vivo. The inflammatory response is triggered by topical application of phorbol esters (TPA) or croton oil constituents, leading to rapid activation of protein kinase C signaling, leukocyte recruitment, and increased vascular permeability, which can be quantified by ear thickness, weight, dye extravasation, and biochemical markers such as myeloperoxidase (MPO) activity and pro-inflammatory mediators in ear tissue homogenates. This model is widely used for screening anti-inflammatory agents, where reductions in edema and inflammatory biomarkers reflect suppression of acute dermal inflammation and immune cell infiltration. Histological evaluation typically confirms epidermal

Bimolecular fluorescence complementation detects protein-protein proximity in living or fixed cells by fusing two candidate interaction partners to nonfluorescent N- and C-terminal fragments of a fluorescent protein; when the partners interact or remain close enough, the fluorescent fragments complement, mature, and generate a fluorescent signal at the site of the protein complex. The BiFC readout is fluorescence intensity and subcellular localization of the reconstituted fluorophore, which reflects formation or stabilization of a protein complex rather than direct biochemical binding kinetics; BiFC is therefore useful for mapping where interactions occur in cancer cells, neurons, macrophages, organoid-derived cells, or drug-screening systems, but results should be validated by independent assays such as co-IP or Western blot. BiFC signal formation is delayed by fluorophore maturation and can stabilize otherwise transient complexes, so it is not a real-time reversible interaction assay

Real-time quantitative PCR (qPCR) quantifies an amplifiable nucleic-acid target by monitoring fluorescence during PCR cycling rather than measuring product only after amplification. The increase in fluorescence tracks accumulation of PCR product, and the quantification cycle (Cq; historically also Ct/CP) is related to the initial amount of target: samples containing more starting target generally reach the defined fluorescence threshold in fewer cycles.

Co-immunoprecipitation technology can verify protein interaction based on the specific immune reaction between antibodies and antigens.

The yeast two-hybrid assay detects binary protein-protein interactions by separating a transcription factor into a DNA-binding domain fused to a "bait" protein and a transcriptional activation domain fused to a "prey" protein; if bait and prey interact in yeast, the transcription factor is reconstituted and activates reporter genes such as HIS3, ADE2, lacZ, MEL1, or other selectable/readable reporters. The readout is yeast growth on selective medium and/or reporter activity, which reflects proximity-dependent transcriptional activation in the yeast nucleus rather than direct biochemical binding in the original mammalian, tumor, neuronal, macrophage, or organoid context. Because yeast two-hybrid can generate false positives and false negatives, interaction claims should be validated using independent assays such as co-immunoprecipitation, Western blot, immunofluorescence colocalization, BiFC, pull-down, or mammalian two-hybrid assays.