human hek293t  (ATCC)

Journal: iScience

Article Title: Single-granule profiling reveals that RNP granule pH marks cellular translation

doi: 10.1016/j.isci.2026.116203

Figure Lengend Snippet: Variation in pH of RNP granules and translation activity of cells under stresses (A) Schematic of stress treatment and indicator detection. (B) pH values of P-bodies and SGs under different stress conditions. Data are represented as mean ± SD ( n = 5 cells with at least 12 granules). (C) Schematic of changes in translation activity in cells exposed to stresses. (D) Cell viability of HEK293T cells facing different stresses. Data are represented as mean ± SD ( n = 3). (E) Principle of nascent protein synthesis detection. (F and G) Levels of protein synthesis in HEK293T cells under different stresses. Data in (F) are represented as mean ± SD ( n = 3). Images were representative examples from three independent experiments. Scale bars in (G), 40 μm. Statistical significance was assessed using a non-paired two-tailed t test in (B), (D), and (F) (∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001).

Article Snippet: Human: HEK293T , Procell , RRID: CVCL_0063.

Techniques: Activity Assay, Two Tailed Test

Journal: Neurobiology of Stress

Article Title: USP11 drives stress-induced synaptic structural deficits and depression-like behaviors through GSK3β/mTOR signaling

doi: 10.1016/j.ynstr.2026.100791

Figure Lengend Snippet: USP11 directly interacts with GSK3β. (A) Volcano plot of proteins detected after USP11 immunoprecipitation from mouse mPFC. Log2 fold change (x-axis) shows enrichment versus control; log2 intensity (y-axis) reflects normalized quantitation in experimental samples. USP11 served as bait; GSK3β is highlighted as an interactor (log2 intensity USP11 = 22.9, log2FC = 2.38). (B) Immunoprecipitation (IP) with anti-USP11 antibody, immunoblot (IB) detection for USP11 (110 kDa) and GSK3β (47 kDa). IP with anti-GSK3β or anti-USP11 antibody. Input: whole lysate; IgG: isotype control. (C) Validation in HEK293T transfection system: lysates of vector control or Flag-USP11 transfected cells (Flag tag, 110 kDa) subjected to IP (anti-GSK3β), IB for anti-USP11. (D) Cell lysate analysis of HEK293T single His-GSK3β, single Flag-USP11, or co-transfected groups, immunoblotted for His-GSK3β (47 kDa) and Flag-USP11 (110 kDa). (E, F) Reciprocal Co-IP verification from HEK293T co-transfection. Immunoblot analysis for His and Flag tag in His-GSK3β, Flag-USP11, and co-transfected samples. (E) Lane 1: His-GSK3β group (IP-His), Lane 2: Flag-USP11 group (IP-Flag), Lane 3: Co-transfection (IP- His) (F) Lane 1: His -GSK3β group (IP- His), Lane 2: Flag-USP11 group (IP-Flag), Lane 3: Co-transfection (IP-Flag). (G) Dot blot analysis showing specific binding between USP11 and GSK3β. BSA (100/200/500 ng) served as negative control, and purified USP11 (100/200/500 ng) was spotted on the same nitrocellulose membrane. After incubation with GSK3β protein solution, binding was detected by fluorescence imaging. (H) Immunofluorescence analysis of co-localization: Exogenous expression in HEK293T cells demonstrates USP11 (red) and GSK3β (green); endogenous expression verified in primary neurons. Nuclei stained with DAPI (blue), scale bar = 25 μm. (I) Fluorescence intensity profiles along linear ROIs: Gray values of USP11 (red) and GSK3β (green) measured with ImageJ. Dual-channel curves plotted in GraphPad Prism using exported data. (J) Pearson's correlation scatter plots for USP11(red) and GSK3β(green) fluorescence, generated using ScatterJ plugin for ImageJ. Pearson's r value shown. (K) Schematic of Flag-tagged USP11 fragment constructs used for pulldown mapping. (L) HEK293T cells were co-transfected with Flag-USP11 or its deletion mutant and His- GSK3β, followed by immunoprecipitation and immunoblot analysis for Flag and His. (M) Computational molecular docking predicts multiple direct contact sites between USP11 and GSK3β.

Article Snippet: Human embryonic kidney 293T (HEK293T) cells were obtained from Procell Life Science & Technology Co., Ltd. (Wuhan, China).

Techniques: Immunoprecipitation, Control, Quantitation Assay, Western Blot, Biomarker Discovery, Transfection, Plasmid Preparation, FLAG-tag, Co-Immunoprecipitation Assay, Cotransfection, Dot Blot, Binding Assay, Negative Control, Purification, Membrane, Incubation, Fluorescence, Imaging, Immunofluorescence, Expressing, Staining, Generated, Construct, Mutagenesis

Journal: Neurobiology of Stress

Article Title: USP11 drives stress-induced synaptic structural deficits and depression-like behaviors through GSK3β/mTOR signaling

doi: 10.1016/j.ynstr.2026.100791

Figure Lengend Snippet: USP11 regulates GSK3β ubiquitination, phosphorylation, and synaptic protein homeostasis in neural cells (A) Western blot analysis of GSK3β ubiquitination in HEK293T cells co-transfected with Flag-vector (control), Flag-USP11 (wild-type, 110 kDa), or Flag-USP11-C318S (catalytically inactive mutant). Endogenous GSK3β and phosphorylated GSK3β at Ser9 were immunoprecipitated from cell lysates using anti-GSK3β antibody, and ubiquitination levels were detected by immunoblotting with anti-ubiquitin antibody. GSK3β: 47 kDa; ubiquitin bands detected as smear. (B) Western blot analysis of GSK3β phosphorylation in three 293T cell groups: wild-type (Ctrl), stable USP11-overexpressing line generated by lentiviral transduction (USP11-OE), and USP11-overexpressing cells subjected to siRNA knockdown (USP11-OE + siUSP11). siUSP11 was transfected to silence USP11 in the stable overexpressing cell line. Whole cell lysates were analyzed for endogenous USP11 (110 kDa), phosphorylated GSK3β at Ser9 (p-GSK3β, 47 kDa), total GSK3β (47 kDa), and GAPDH (35 kDa) as loading control. Representative results from n = 3 biological replicates per group. (C) Gray value quantification of p-GSK3β/t-GSK3β in 293T cells (n = 3, F (2, 6) = 35.38, p = 0.0005). (D) Western blot analysis of USP11 (110 kDa), phosphorylated mTOR (p-mTOR, Ser2448, 289 kDa), total mTOR (289 kDa), p-GSK3β (Ser9, 47 kDa), total GSK3β (47 kDa), and Tubulin (55 kDa) in primary neurons upon USP11 siRNA knockdown (n = 3). (E, F) Gray value quantification of p-GSK3β/t-GSK3β, and p-mTOR/t-mTOR ratios in neurons upon USP11 siRNA knockdown (n = 3, p-GSK3β, p = 0.0213, p-mTOR, p = 0.0047). (G) Immunoblot of USP11 (110 kDa), p-GSK3β (Ser9, 47 kDa), total GSK3β (47 kDa), SYN (77 kDa), and Tubulin (55 kDa) in primary neurons infected with adeno-associated virus (AAV) (n = 3). (H, I) Gray value quantification of p-GSK3β/t-GSK3β, and SYN/Tubulin ratios in neurons transduced with vector or AAV-USP11 viruses (n = 3, p-GSK3β, p = 0.0078, SYN, Welch's t -test, p = 0.0031). (J) Representative immunofluorescence of primary neurons transduced with vector or AAV-USP11 viruses, showing DAPI (blue, nuclei), SYN (green, synaptophysin), and USP11 (magenta); merged panels display synapse integrity. Scale bar: 50 μm. (K, L) Quantitative analysis from three independent biological replicates in primary neurons transduced with vector or AAV-USP11 viruses (K) Mean USP11 immunofluorescence intensity (p = 0.0416), (L) Mean SYN immunofluorescence intensity (p = 0.0035). Data are shown as mean ± SEM. Determined by t -test (baseline comparisons) or one-way ANOVA (multiple groups) unless otherwise indicated. ∗p < 0.05, ∗∗p < 0.01, ∗∗∗p < 0.001.

Article Snippet: Human embryonic kidney 293T (HEK293T) cells were obtained from Procell Life Science & Technology Co., Ltd. (Wuhan, China).

Techniques: Ubiquitin Proteomics, Phospho-proteomics, Western Blot, Transfection, Plasmid Preparation, Control, Mutagenesis, Immunoprecipitation, Generated, Transduction, Knockdown, Infection, Virus, Immunofluorescence

Journal: Virulence

Article Title: FGF8-mediated TRIM16 regulation promotes K48-linked ubiquitination and degradation of RIG-I to facilitate Influenza a virus immune evasion

doi: 10.1080/21505594.2026.2677346

Figure Lengend Snippet: Identification of the ubiquitination site on RIG-I targeted by FGF8. (a) diagram illustrating the truncated constructs of RIG-I. (b) HEK-293T cells were co-transfected with specified plasmids and exposed to MG132 for 6 hours. Western blot analysis was conducted to assess the ubiquitination of various RIG-I truncation constructs. (C) Western blot analysis identified the ubiquitination site on RIG-I targeted by FGF8, and band intensities were quantified by densitometry to assess the degradation of each mutant. (d) a dual-luciferase assay was conducted in HEK293T cells co-transfected with specified RIG-I mutants and FGF8 to evaluate the impact of FGF8 on IFN-β promoter activity. Error bars indicate the mean ± SEM from three independent experiments. Two-tailed unpaired Student’s t-tests were used. ns (not significant), * p < 0.05, ** p < 0.01, and *** p < 0.001.

Article Snippet: Human lung adenocarcinoma cell line A549 (Procell Life Science & Technology Co., Ltd., Wuhan, China; Cat. No. CL-0016), human embryonic kidney cell line HEK293T (Procell Life Science & Technology Co., Ltd., Wuhan, China; Cat. No. CL-0005), and Madin-Darby canine kidney cell line MDCK (Procell Life Science & Technology Co., Ltd., Wuhan, China; Cat. No. CL-0154) were used for virus infection experiments, protein interaction validation experiments, and virus titration assays, respectively.

Techniques: Ubiquitin Proteomics, Construct, Transfection, Western Blot, Mutagenesis, Luciferase, Activity Assay, Two Tailed Test

Journal: iScience

Article Title: Localized phosphoinositide metabolism regulates STIM1/ORAI1 fast inactivation

doi: 10.1016/j.isci.2026.115543

Figure Lengend Snippet: Catalytically active MTMR7 is essential for STIM1/ORAI1 activity (A) Schematic representation of the MTMR7 protein domains. The PH-GRAM domain is shown in yellow, the catalytic protein tyrosine phosphatase (PTP) domain in green, and the coiled-coil (CC) domain in pink. The location of the STIM1 binding region at the C-terminus of MTMR7 is indicated in the figure. The location of the stop codon introduced at the N-terminal amino acid residues of the STIM1 interaction site (S569∗) is indicated by a red X, the location of C338S and D343A mutations in the catalytic PTP domain is indicated by blue arrows. (B) Immunoblot analysis of wild-type and MTMR7 mutants expressed in HEK293T cells. Anti-GAPDH was used as a loading control. (C and D) Co-immunoprecipitation of MTMR7 and STIM1 in HEK293T cells co-transfected with STIM1-YFP and either MTMR7, MTMR-C338S, or MTMR-D343A mutants. Immunoprecipitation was performed using GFP-Trap agarose beads, followed by immunoblotting with anti MTMR7 ( C ) and anti STIM1 ( D ) antibodies. (E) Representative whole-cell current traces of heterologously expressed ORAI1 and STIM1, along with MTRM7 or MTMR7 mutants MTMR7-C338S, MTMR7-D343A, and MTMR7-S569∗ in MTMR7 −/− cells. Cells were transfected in a 1:2:1 (ORAI1:STIM1:MTMR7 or MTMR7 mutants) ratio. Currents were recorded in 20 mM Ca 2+ during 200 ms hyperpolarizing test voltages (−60, −80, −100, and −120 mV) from a 30-mV holding potential. (F) Current density (pA/pF) analysis of current from a −100-mV hyperpolarizing pulse at 3 min following whole-cell break-in (white bars; n = 6–13 for each group). Green bar denotes the current density measured from a −100-mV pulse at 15 min following whole-cell break-in ( n = 3). A nonparametric Kruskal-Wallis ANOVA on ranks test, followed by a multiple comparison (Dunn’s) post hoc test, was used to compare each group against either the control ( Ctrl ) condition in wild-type or MTMR7 −/− MEF cells (∗ p < 0.001 vs. wild-type, # p < 0.01 vs. MTMR7 −/− ). (G) Extent of STIM1/ORAI1 CDI from recordings of each group shown in F. Line and scatterplot summarizing the fraction of current remaining for each group, measured as the percent of peak current from the beginning and the end of the 200 ms hyperpolarizing steps. Each data point represents the mean ± SEM ( n = 6–15 cells for each group). For comparison, the data from wild-type or MTMR7 −/− cells were superimposed from D in gray and black dashed lines, respectively. A one-way ANOVA followed by a Dunnett’s post hoc test was used to compare the residual current of all groups against the control (WT) (∗ p < 0.05 at all test potentials). Data are represented as mean ± SEM.

Article Snippet: Human: HEK293T (female) , ATCC , Cat# MSPP-CRL3216).

Techniques: Activity Assay, Binding Assay, Western Blot, Control, Immunoprecipitation, Transfection, Comparison

Journal: iScience

Article Title: Localized phosphoinositide metabolism regulates STIM1/ORAI1 fast inactivation

doi: 10.1016/j.isci.2026.115543

Figure Lengend Snippet: MTMR7 double mutants and ORAI1 inactivation (A) Immunoblot analysis of HEK293T cells expressing MTMR7 and MTMR7 mutants (MTMR7-C338S, MTMR7-D343A, MTMR7-C338S + S569∗, and MTMR7-D343A + S569∗). (B) Representative whole-cell current traces of heterologously expressed ORAI1 and STIM1, along with MTMR7 double mutants; MTMR7-C338S + S569∗ or MTMR7-D343A + S569∗ in MTMR7 −/− cells. Cells were transfected in a 1:2:1 (ORAI1:STIM1:MTMR7 double mutants) ratio. Currents were recorded in 20 mM Ca 2+ during 200 ms hyperpolarizing test voltages (−60, −80, −100, −120 mV) from a 30-mV holding potential. (C) Current density (pA/pF) analysis of current from a −100-mV hyperpolarizing pulse at 3 min following whole-cell break-in (white bars; n = 7 for each group). (D) Extent of STIM1/ORAI1 CDI from recordings of each group shown in F. Line and scatterplot summarizing the fraction of current remaining for each group, measured as the percent of peak current from the beginning and the end of the 200 ms hyperpolarizing steps. Each data point represents the mean ± SEM (n = 8–9 cells for each group). For comparison, the data from wild-type MEF or MTMR7 −/− cells were superimposed from D in gray and black dashed lines, respectively. A one-way ANOVA followed by a Dunnett’s post hoc test was used to compare the residual current of all groups against the control (WT) (∗ p < 0.05 at all test potentials). Data are represented as mean ± SEM.

Article Snippet: Human: HEK293T (female) , ATCC , Cat# MSPP-CRL3216).

Techniques: Western Blot, Expressing, Transfection, Comparison, Control

Journal: Redox Biology

Article Title: SMURF2 attenuates NRF2-driven tumor progression by acting as a nuclear brake on NRF2 during cellular stress

doi: 10.1016/j.redox.2026.104102

Figure Lengend Snippet: SMURF2 prohibits the stress-mediated formation of ub + /p62 + aggresomes. (A and B) LN229 cells were transfected with HA or HA-SMURF2 and treated with DMSO; MG132 (10 μM, 12 h); H 2 O 2 (200 μM, 2 h); or LPS (100 ng/mL, 12 h). Representative immunofluorescence (IF) images of the colocalization of ub and p62. Nuclei stained with DAPI (A). Quantification the percentage of cells with ub + /p62 + puncta (B). (C – E) HEK293T cells were transfected with HA or HA-SMURF2 and subsequently treated with MG132 (10 μM, 12 h) or H 2 O 2 (200 μM, 2 h). Detergent-soluble and detergent-insoluble fractions were analyzed by western blotting with indicated antibodies (C and D). Quantification of the relative intensity of ub and p62 levels in the detergent-insoluble fractions shown in C and D (E). (F) LN229 cells were transfected with HA or HA-SMURF2 and treated with DMSO; MG132 (10 μM, 12 h); H 2 O 2 (200 μM, 2 h); or LPS (100 ng/mL, 12 h). Representative IF images of the colocalization of Proteostat and p62. Nuclei stained with DAPI. (G) The proposed model suggests that SMURF2 inhibits the formation of ub + /p62 + aggresomes/ALIS under stress conditions. Data were presented as the mean ± SD from three independent experiments. NS: not significant, ∗∗ p < 0.01, ∗∗∗ p < 0.001. Scale bar: 10 μm. Short Exp: short exposure; Long Exp: long exposure.

Article Snippet: The human glioblastoma cell lines LN229 and human embryonic kidney 293T (HEK293T) cell lines were purchased from the American Type Culture Collection (ATCC).

Techniques: Transfection, Immunofluorescence, Staining, Western Blot

Journal: Redox Biology

Article Title: SMURF2 attenuates NRF2-driven tumor progression by acting as a nuclear brake on NRF2 during cellular stress

doi: 10.1016/j.redox.2026.104102

Figure Lengend Snippet: SMURF2 promotes NRF2 proteasomal degradation in response to cellular stress. (A) Co-immunoprecipitation (Co-IP) assay was performed to analyze the interaction between SMURF2 and NRF2. (B) Co-IP assay analysis of the interaction between HA-SMURF2 and His-Flag-NRF2 after treated with or without H 2 O 2 (200 μM, 2 h) (C) Endogenous co-IP assay analysis of the interaction between endogenous SMURF2 and NRF2 in HEK293T cells after treated with or without H 2 O 2 (200 μM, 2 h). (D and E) Co-IP assay analysis of the interaction between His-Flag-SMURF2 constructs (WT, C2, WW3 and ΔHECT) and Myc-NRF2 (D); the interaction between GST-SMURF2 constructs (ΔC2 and ΔWW3) and HA-NRF2 (E). (F) Co-IP assay analysis of the interaction between His-Flag-NRF2 constructs (WT and ΔNeh1-6) and HA-SMURF2. (G) Schematic diagram of mapping the direct interaction between SMURF2 and NRF2. (H) HEK293T cells expressing Flag-NRF2 were treated with MG132 (10 μM,12 h). The ubiquitination of Flag-NRF2 in the presence of purified GST or GST-SMURF2 was then detected by western blotting. (I) HEK293T cells were transfected with SMURF2 siRNA or scramble siRNA for 48 h, then transfected with HA-NRF2 and restored with Flag-SMURF2-WT/CS/CS C716A , treated with MG132 (10 μM, 12 h). Ubiquitination of HA-NRF2 was assessed by co-IP after SMURF2 knockdown and functional restoration. (J) HEK293T cells expressing HA-NRF2 and Flag-Ub-K48 or Flag-Ub-K63. The K48-linked or K63-linked ubiquitination of HA-NRF2 in the presence of purified GST or GST-SMURF2 was then detected by western blotting. (K) HEK293T cells were transfected with either HA or HA-SMURF2, then treated with DMSO, MG132 (10 μM, 12 h) or Bafilomycin A1 (Baf-A1, 100 nM, 6 h) and analyzed by western blotting of whole cell lysates (WCL) using the indicated antibodies. (L – O) HEK293T cells were transfected either with HA or HA-SMURF2 (L), or with SMURF2 siRNA or scramble siRNA oligos for 48 h (N), then treated with cycloheximide (CHX, 100 μg/mL) for the indicated times and analyzed by western blotting using the indicated antibodies. Quantification of the relative intensity of NRF2 is shown (M, O). (P) HEK293T cells were transfected with either Flag or Flag-SMURF2, then treated with PBS, H 2 O 2 (200 μM, 2 h), or LPS (100 ng/mL, 12 h) and analyzed by western blotting using the indicated antibodies. (Q) HEK293T cells were transfected with either HA or HA-SMURF2, then treated with PBS or LPS (100 ng/mL, 12 h) and analyzed by qRT-PCR using primers specific for indicated genes. The fold change in expression in HA-SMURF2 overexpressing samples was calculated relative to control samples. (R) HEK293T cells were transfected with SMURF2 siRNA or scramble siRNA oligos for 48 h, then treated with PBS, H 2 O 2 (200 μM, 2 h), or LPS (100 ng/mL, 12 h) and analyzed by western blotting using the indicated antibodies. (S) HEK293T cells were transfected with SMURF2 siRNA or scramble siRNA oligos for 48 h, then treated with PBS or LPS (100 ng/mL, 12 h) and analyzed by qRT-PCR using primers specific for indicated genes. The fold change in expression in si-SMURF2 samples was calculated relative to control samples. Data were presented as the mean ± SD from three independent experiments. ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001.

Article Snippet: The human glioblastoma cell lines LN229 and human embryonic kidney 293T (HEK293T) cell lines were purchased from the American Type Culture Collection (ATCC).

Techniques: Co-Immunoprecipitation Assay, Construct, Expressing, Ubiquitin Proteomics, Purification, Western Blot, Transfection, Knockdown, Functional Assay, Quantitative RT-PCR, Control

Journal: Redox Biology

Article Title: SMURF2 attenuates NRF2-driven tumor progression by acting as a nuclear brake on NRF2 during cellular stress

doi: 10.1016/j.redox.2026.104102

Figure Lengend Snippet: SMURF2 nuclear translocation facilitates the degradation of NRF2 within the nucleus. (A and B) HEK293T cells were first transfected with HA-NRF2-WT. Subsequently, cells were transfected either with Flag or Flag-SMURF2 (A), or with SMURF2 siRNA or scrambled siRNA oligos for 48 h (B). Cells were then treated with H 2 O 2 (200 μM, 2 h) or LPS (100 ng/mL, 12 h). Following treatment, subcellular fractionation was performed to isolate total, nuclear, and cytoplasmic proteins, followed by western blot analysis with indicated antibodies. (C and D) LN229 cells were transfected with HA-SMURF2, then treated with PBS, H 2 O 2 (200 μM, 2 h) (C) or LPS (100 ng/mL, 12 h) (D). Representative IF images showing the subcellular localization of HA-SMURF2 are presented; nuclei were stained with DAPI. (E and F) HEK293T cells were treated with PBS, H 2 O 2 (200 μM, 2 h) (E), or LPS (100 ng/mL, 12 h) (F). Subcellular fractionation was performed to isolate total, nuclear, and cytoplasmic proteins, followed by western blot analysis with indicated antibodies. (G) Schematic depiction of NRF2 NLS1/2−Mut , NRF2 NES1/2−Mut , and SMURF2 NLS−Mut . (H–K) HEK293T cells were first transfected with HA-NRF2 NLS2−Mut (H and I) or HA-NRF2 NES2−Mut (J and K). Subsequently, cells were transfected either with Flag or Flag-SMURF2, then treated with H 2 O 2 (200 μM, 2 h) (H and J) or LPS (100 ng/mL, 12 h) (I and K). Following treatment, subcellular fractionation was performed to isolate total, nuclear, and cytoplasmic proteins, followed by western blot analysis with indicated antibodies. (L) Schematic of SMURF2 domains with NLS indicated (single-letter code). SMURF2 NLS−Mut denotes deletion of NLS residues (Top). LN229 cells transfected with Flag-SMURF2-WT or Flag-SMURF2 NLS−Mut were treated with DMSO, MG132 (10 μM, 12 h), H 2 O 2 (200 μM, 2 h), or LPS (100 ng/mL, 12 h). Representative IF images showing subcellular localization of Flag-SMURF2 or Flag-SMURF2 NLS−Mut ; nuclei were stained with DAPI (Bottom). (M) HEK293T cells were first transfected with HA-NRF2-WT. Subsequently, cells were transfected either with Flag or Flag-SMURF2 NLS−Mut , then treated with H 2 O 2 (200 μM, 2 h) or LPS (100 ng/mL, 12 h). Following treatment, subcellular fractionation was performed to isolate total, nuclear, and cytoplasmic proteins, followed by western blot analysis with indicated antibodies. (N) The proposed model indicates that SMURF2 specifically degrades NRF2 in the nucleus. Scale bar: 5 μm, Scale bar: 10 μm. Data were presented in three independent experiments.

Article Snippet: The human glioblastoma cell lines LN229 and human embryonic kidney 293T (HEK293T) cell lines were purchased from the American Type Culture Collection (ATCC).

Techniques: Translocation Assay, Transfection, Fractionation, Western Blot, Staining

Journal: Redox Biology

Article Title: SMURF2 attenuates NRF2-driven tumor progression by acting as a nuclear brake on NRF2 during cellular stress

doi: 10.1016/j.redox.2026.104102

Figure Lengend Snippet: SMURF2 ubiquitinates NRF2 at K555 in the nucleus for its degradation. (A) HEK293T cells were transfected with HA-NRF2 constructs (ΔNeh1-ΔNeh6), followed by treatment with MG132 (10 μM, 12 h). The ubiquitination of HA-NRF2 constructs (ΔNeh1-ΔNeh6) in the presence of purified GST or GST-SMURF2 was then detected by western blotting. (B) HEK293T cells were transfected with HA-NRF2 constructs (Δ434-500, Δ501-539 and Δ540-561), followed by treatment with MG132 (10 μM, 12 h). The ubiquitination of HA-NRF2 constructs (Δ434-500, Δ501-539 and Δ540-561) in the presence of purified GST or GST-SMURF2 was then detected by western blotting. (C) HEK293T cells were transfected with HA-NRF2 constructs (K554R/K555R and K541R/K543R/K548R), followed by treatment with MG132 (10 μM, 12 h). The ubiquitination of HA-NRF2 constructs (K554R/K555R and K541R/K543R/K548R) in the presence of purified GST or GST-SMURF2 was then detected by western blotting. (D) HEK293T cells were transfected with HA-NRF2 constructs (K554R and K555R), followed by treatment with MG132 (10 μM, 12 h). The ubiquitination of HA-NRF2 constructs (K554R and K555R) in the presence of purified GST or GST-SMURF2 was then detected by western blotting. (E) Purified SMURF2 with His-ub, E1, E2 (UbcH5c), and ATP were used as indicated and evaluated by pull-down assay. Ubiquitinated NRF2-WT and K555R detected by immunoblotting against anti-Ub and anti-Flag. (F) Sequence alignment of NRF2 sites on CNA orthologs of different species. (G) HEK293T cells overexpressing HA-NRF2 were transfected with Flag or Flag-SMURF2, followed by treatment with MG132 (10 μM, 12 h). Following treatment, subcellular fractionation was performed to isolate cytoplasmic and nuclear fractions. The ubiquitination of cytoplasmic and nuclear fractions was then detected by western blotting. (H) HEK293T cells were transfected with HA-NRF2 NLS1−Mut , HA-NRF2 NES1−Mut , HA-NRF2 NLS2−Mut or HA-NRF2 NES2−Mut , followed by treatment with MG132 (10 μM, 12 h). The ubiquitination of HA-NRF2 constructs in the presence of purified GST or GST-SMURF2 was then detected by western blotting. (I and J) HEK293T cells were first transfected with HA-NRF2 (I), or HA-NRF2-K555R (J), then were transfected with Flag or Flag-SMURF2, followed by treatment with MG132 (10 μM, 12 h) (I), H 2 O 2 (200 μM, 2 h) or LPS (100 ng/mL, 12 h) (J). Following treatment, subcellular fractionation was performed to isolate total, nuclear, and cytoplasmic proteins, followed by western blot analysis with indicated antibodies. Data were presented in three independent experiments.

Article Snippet: The human glioblastoma cell lines LN229 and human embryonic kidney 293T (HEK293T) cell lines were purchased from the American Type Culture Collection (ATCC).

Techniques: Transfection, Construct, Ubiquitin Proteomics, Purification, Western Blot, Pull Down Assay, Sequencing, Fractionation

Journal: Redox Biology

Article Title: SMURF2 attenuates NRF2-driven tumor progression by acting as a nuclear brake on NRF2 during cellular stress

doi: 10.1016/j.redox.2026.104102

Figure Lengend Snippet: SMURF2 promotes cell apoptosis through NRF2 inactivation. (A) LN229 cells were transfected with HA, HA-SMURF2, Myc-NRF2 or HA-SMURF2 + Myc-NRF2 and subsequent treatment with MG132 (10 μM, 12 h), H 2 O 2 (200 μM, 2 h), or LPS (100 ng/mL, 12 h). Representative IF images of the colocalization of ub and p62. Nuclei stained with DAPI. (B and C) HEK293T cells were transfected with empty vector or Myc-NRF2, followed by Flag or Flag-SMURF2 expression. Western blotting was performed using indicated antibodies (B). qRT-PCR was performed using primers specific for indicated genes (C). The fold change in expression in Flag-SMURF2 overexpressing samples was calculated relative to control samples. (D) HEK293T cells were first transfected with NRF2 siRNA for 48 h, followed by transfection with either Myc-NRF2-WT or Myc-NRF2-K555R, and subsequently transfected with Flag or Flag-SMURF2.Western blotting was performed using indicated antibodies. (E) LN229 cells were transfected with SMURF2 siRNA or scramble siRNA oligos for 48 h, followed by treatment with PBS or H 2 O 2 (200 μM, 2 h). Cells were then stained with 2,7-Dichlorodihydrofluorescein diacetate (DCFH-DA, 10 μM) and the ROS level was detected by flow cytometry. (F) Quantification of relative ROS fluorescence intensity in LN229 cells with SMURF2 knockdown or HA-SMURF2 overexpression. (G and H) LN229 cells were transfected with SMURF2 siRNA or scramble siRNA oligos for 48 h or transfected with HA or HA-SMURF2, followed by treatment with PBS or H 2 O 2 (200 μM, 2 h). Cells were then stained with Annexin-V/propidium iodide (PI), and apoptotic cells were detected by flow cytometry (G). Quantification of apoptosis in LN229 cells with SMURF2 knockdown or HA-SMURF2 overexpression (H). (I) HEK293T cells were transfection with Flag or Flag-SMURF2, and subsequent treatment with or without MG132 (10 μM, 12 h), H 2 O 2 (200 μM, 2 h), or LPS (100 ng/ml, 12 h). Western blotting was performed using indicated antibodies. (J and K) HEK293T cells were transfected with empty vector and Myc-NRF2 (J) or Myc-NRF2-WT, Myc-NRF2-K555R (K), followed by Flag or Flag-SMURF2 expression. Cells were subsequently treated with MG132 (10 μM, 12 h), H 2 O 2 (200 μM, 2 h), or LPS (100 ng/mL, 12 h). Western blotting was performed using indicated antibodies. (L) The shSMURF2 and shPLKO cells were treated with or without LPS (100 ng/mL, 12 h) and cultured for 14 days. Colony formation assay was performed for cells. (M) The representative images of shSMURF2 and shPLKO patient-derived cells formed tumors in nude mice with or without LPS (10 mg/kg). (N) The graph showed the quantified data of tumor weight. (O) Immunohistochemistry (IHC) analysis of tumor tissue slides with antibodies against Ki67. Nucleus was stained by hematoxylin. Scale bar, 50 μm (P) The proposed model indicates that SMURF2 promotes cell apoptosis through NRF2 inactivation. Data were presented as the mean ± SD from three independent experiments. ∗ p < 0.05, ∗∗ p < 0.01, ∗∗∗ p < 0.001. Scale bar: 10 μm, Scale bar, 50 μm.

Article Snippet: The human glioblastoma cell lines LN229 and human embryonic kidney 293T (HEK293T) cell lines were purchased from the American Type Culture Collection (ATCC).

Techniques: Transfection, Staining, Plasmid Preparation, Expressing, Western Blot, Quantitative RT-PCR, Control, Flow Cytometry, Fluorescence, Knockdown, Over Expression, Cell Culture, Colony Assay, Derivative Assay, Immunohistochemistry

Journal: Redox Biology

Article Title: SMURF2 attenuates NRF2-driven tumor progression by acting as a nuclear brake on NRF2 during cellular stress

doi: 10.1016/j.redox.2026.104102

Figure Lengend Snippet: SMURF2 promotes NRF2 hi patient survival. (A) HA-NRF2 overexpressing HEK293T cells were transfected with GFP or GFP-KEAP1, followed by transfection with Flag or Flag-SMURF2. Co-IP analysis of the interaction between HA-NRF2 and GFP-KEAP1 in WCL. (B) Myc-NRF2 overexpressing HEK293T cells were transfected with HA or HA-KEAP1, followed by transfection with Flag or Flag-SMURF2. Co-IP analysis of the interaction between Myc-NRF2 and HA-KEAP1 in the cytoplasm. (C) HA-NRF2 overexpressing HEK293T cells were transfected with GFP or GFP-KEAP1, followed by transfection with SMURF2 siRNA or scramble siRNA oligos for 48 h. Co-IP analysis of the interaction between HA-NRF2 and GFP-KEAP1 in the cytoplasm under with or without SMURF2. (D) HEK293T cells were initially transfected with KEAP1 siRNA for 48 h, followed by transfection with HA-NRF2-WT, and subsequently transfected with Flag or Flag-SMURF2. Subcellular fractionation was performed to isolate total, nuclear, and cytoplasmic proteins, followed by western blot analysis with indicated antibodies. (E) HEK293T cells were first transfected with HA-NRF2-WT. Subsequently, cells were transfected either with Flag or Flag-KEAP1. Subcellular fractionation was performed to isolate total, nuclear, and cytoplasmic proteins, followed by western blot analysis with indicated antibodies. (F) GFP-KEAP1 overexpression HEK293T cells were transfected with HA-NRF2-WT, and subsequently transfected with Flag or Flag-SMURF2. Subcellular fractionation was performed to isolate total, nuclear, and cytoplasmic proteins, followed by western blot analysis with indicated antibodies. (G) Co-IP assay analysis of the interaction between HA-KEAP1 and His-Flag-NRF2 after treated with or without H 2 O 2 (200 μM, 2 h) (H) Boxplot of SMURF2 expression (log 2 FPKM) in the NRF2-high/KEAP1-low subset of TCGA-GBMLGG samples. (I) Kaplan-Meier survival analysis of TCGA-GBMLGG patients grouped by expression of SMURF2 in the NRF2-high/KEAP1-low subset ( p = 0.018, HR = 1.7755, log rank test). (J) Clinical feature distribution across SMURF2 expression groups. (K) Forest Plot of Multivariable Cox Proportional Hazards Analysis in High-Grade Gliomas. Data were presented in three independent experiments. ∗∗ p < 0.01; ∗∗∗ p < 0.001.

Article Snippet: The human glioblastoma cell lines LN229 and human embryonic kidney 293T (HEK293T) cell lines were purchased from the American Type Culture Collection (ATCC).

Techniques: Transfection, Co-Immunoprecipitation Assay, Fractionation, Western Blot, Over Expression, Expressing