Journal: Journal of Virology

Article Title: Glycosylated NS3/NS3A protein of bluetongue virus facilitates efficient viral egress via lipid raft anchoring

doi: 10.1128/jvi.02144-25

Figure Lengend Snippet: N-linked glycosylation drives plasma membrane accumulation of NS3/NS3A. ( A ) The stability of NS3/NS3A WT and NS3/NS3A N150Q proteins was examined in both transfected (top panels) and BTV-20-infected cells (bottom panels; MOI = 10). For transfection assays, HEK-293T cells were transfected with plasmids expressing NS3/NS3A WT or the N150Q mutant and treated with cycloheximide (CHX; 100 μg/mL) at 18 h post-transfection (designated as 0 h post-CHX treatment) to block de novo protein synthesis. For infection assays, MDOK cells were infected with BTV-20 WT or BTV-20 N150Q and treated with CHX (100 μg/mL) at 10 h post-infection (designated as 0 h post-CHX treatment). Cells were harvested at the indicated time points and analyzed by Western blotting. ( B ) Quantification of NS3/NS3A protein levels shown in panel A was performed by ImageJ densitometric analysis. Protein levels at each time point were normalized to the corresponding 0 h post-CHX treatment (18 h post-transfection or 10 h post-infection, respectively). ( C ) Subcellular localization of NS3/NS3A in MDOK cells infected with BTV-20 WT or BTV-20 N150Q (MOI = 5, 12 h.p.i.). NS3/NS3A (red) was co-stained with ER marker anti-calnexin (green) or Golgi marker anti-syntaxin 6 (green). Fluorescence distribution was evaluated using line-scan intensity profiles. Scale bar, 5 µm. ( D ) Subcellular localization of NS3/NS3A in MDOK cells infected with BTV-20 WT or BTV-20 N150Q (MOI = 5, 12 h.p.i.). NS3/NS3A (red) was co-stained with plasma membrane marker WGA-Alexa Fluor 488 (green). Line-scan intensity profiles are shown. Scale bar, 5 µm. ( E ) Plasma membrane isolation of HEK-293T cells transfected with NS3/NS3A WT or N150Q mutant, followed by Western blot analysis. PM (plasma membrane fraction); NPM (non-plasma membrane fraction); Total (plasma membrane fraction + non-plasma membrane fraction). ( F ) Quantification of NS3/NS3A at the plasma membrane fraction was analyzed by Image J from panel E (* P < 0.05, two-tailed unpaired t-test). ( G ) Confocal imaging of HeLa cells co-transfected with NS3/NS3A (WT or N150Q, red) and VP2 (green) or VP5 (green), showing their subcellular colocalization. Colocalization was assessed by line-scan intensity profiles.

Article Snippet: Commercial antibodies used in this study included anti-FLAG (DYKDDDDK) monoclonal antibody (1:1,000 for immunofluorescence assay [IFA], 1:10,000 for western blotting [WB]; 66008-4-Ig, Proteintech), anti-HA polyclonal antibody (1:100 for IFA, 1:1,000 for WB; 51064-2-AP, Proteintech), anti-β-actin monoclonal antibody (1:10,000 for WB; 66009-1-Ig, Proteintech), anti-Calnexin polyclonal antibody (1:200 for IFA; 10427-2-AP, Proteintech), anti-Syntaxin 6 polyclonal antibody (1:200 for IFA; 10841-1-AP, Proteintech), anti-Flotillin 1 monoclonal antibody (1:100 for IFA; 67968-1-Ig, Proteintech), and anti-Filamin A (FLNA) monoclonal antibody (1:1,000 for WB; 67133-1-Ig, Proteintech).

Techniques: Glycoproteomics, Clinical Proteomics, Membrane, Transfection, Infection, Expressing, Mutagenesis, Blocking Assay, Western Blot, Staining, Marker, Fluorescence, Isolation, Two Tailed Test, Imaging

Journal: iScience

Article Title: Legionella employs the multimodal ubiquitination of Sec22b to modulate SNARE pairing

doi: 10.1016/j.isci.2025.114341

Figure Lengend Snippet: Ubiquitination of Sec22b promotes non-canonical SNARE pairings with Stx3 and Stx4 (A) HEK293T-FcγRII cells stably expressing FLAG-Sec22b were infected with the indicated L. pneumophila strains at an MOI of 80 for 1 h. FLAG-Sec22b derivatives were immunoprecipitated from the cell lysates at the indicated time points using anti-FLAG beads. The cell lysates (input) and the immunoprecipitated proteins (IP: FLAG) were analyzed by SDS-PAGE and immunoblotting with the indicated antibodies. The intensity values of Stx3 protein bands were quantified using the ChemiDoc System with Image Lab software (Bio-Rad), normalized to the value of the no-infection condition (no bacteria), and displayed below the immunoblotting data. (B) HEK293T-FcγRII cells stably expressing FLAG-Sec22b S137A were infected with the indicated L. pneumophila strains at an MOI of 80 for 1 h, and analyzed as described in (A). The intensity values of Stx3 protein bands were quantified as described in (A) and displayed below the immunoblotting data. (C) HEK293T-FcγRII cells stably expressing FLAG-Sec22b or FLAG-Sec22b S137A were infected with the wild-type strain Lp01 at an MOI of 80 for 1 h, and analyzed as described in (A). (D) Intensity values of Stx3, Stx4, and Stx18 protein bands from (C) quantified as described in (A), normalized to the respective Syntaxin values bound to Sec22b WT. Values represent the mean ± SEM from three independent experiments. ns, not significant. ∗ p < 0.05, ∗∗∗∗ p < 0.0001.

Article Snippet: Anti-Stx3 rabbit polyclonal antibody (15556-1-AP) and anti-Stx4 rabbit monoclonal antibody (14988-1-AP) were purchased from Proteintech.

Techniques: Ubiquitin Proteomics, Stable Transfection, Expressing, Infection, Immunoprecipitation, SDS Page, Western Blot, Software, Bacteria