Journal: bioRxiv

Article Title: Identification of Human Transferrin Receptor as an Entry Co-receptor for Parvovirus B19 Infection of Human Erythroid Progenitor Cells

doi: 10.64898/2026.04.02.715920

Figure Lengend Snippet: (A) Protein diagram. VP1u-APEX2 consists of APEX2 fused to the C-terminus of the unique region of B19V VP1 (VP1u) via a seven-residue glycine-serine linker (GGSGGSG), followed by a Flag tag and a 6 × Histidine (His) tag. APEX2 has a linker-Flag-His tag fused at the C-terminus. (B) Analysis of purified proteins. VP1u-APEX2 and APEX2 proteins were expressed in bacteria and purified. Approximately (∼) 1 µg of each protein was separated by SDS-PAGE, followed by Coomassie blue staining. M, molecular weight marker. (C) Confocal microscopy of VP1u-APEX2 entry. 1 × 10 6 UT7/Epo-S1 cells were incubated with 2 μM VP1u-APEX2 or APEX2 protein at 37°C for 2 h. The cells were then immunostained with α-Flag to visualize internalized proteins under a Leica STED confocal microscope. Scale bar = 10 μm. Nuclei were stained with DAPI (4’,6-diamidino-2-phenylindole). (D) Western blotting of APEX2-biotinylated proteins. 1 × 10 7 UT7/Epo-S1 cells were incubated with 2 μM VP1u-APEX2 or APEX2 protein at 37°C. After 2 h, APEX2-mediated biotinylation was then performed as described in the Materials and Methods and Figure S1 . Biotinylated host proteins were purified with streptavidin-conjugated magnetic beads. The supernatant was collected as the flow-through (FT), and the beads were further washed several times and eluted as the pull-down (PD). Both FT and PD samples were analyzed by SDS-PAGE and immunoblotting using Alexa Fluor 680-conjugated streptavidin. (E) Analysis of VP1u-APEX2-biotinylated/associated proteins using quantitative mass spectrometry (qMS). Three independent PD samples prepared from VP1u-APEX2 and APEX2 (control) treated cells were analyzed by on-bead digestion and qMS. MS data were processed and analyzed as described in the Materials and Methods. The bubble plot shows protein enrichment (log 2 fold change) in the VP1u-APEX2 group relative to the APEX control, with color indicating subcellular localization based on Gene Ontology (GO) annotation. TFRC denotes human transferrin receptor 1 (hTfR).

Article Snippet: Purified proteins: Recombinant hTfR ECD protein tagged with a His-tag at the C-terminus (#11020-H07H) and recombinant human ferritin heavy chain 1/FTH1 (#13217-HNAE) were purchased from SinoBiological (Paoli, PA).

Techniques: Residue, FLAG-tag, Purification, Bacteria, SDS Page, Staining, Molecular Weight, Marker, Confocal Microscopy, Incubation, Microscopy, Western Blot, Magnetic Beads, Mass Spectrometry, Control, Protein Enrichment

Journal: bioRxiv

Article Title: Identification of Human Transferrin Receptor as an Entry Co-receptor for Parvovirus B19 Infection of Human Erythroid Progenitor Cells

doi: 10.64898/2026.04.02.715920

Figure Lengend Snippet: (A) Protein diagram. VP1u-APEX2 consists of APEX2 fused to the C-terminus of the unique region of B19V VP1 (VP1u) via a seven-residue glycine-serine linker (GGSGGSG), followed by a Flag tag and a 6 × Histidine (His) tag. APEX2 has a linker-Flag-His tag fused at the C-terminus. (B) Analysis of purified proteins. VP1u-APEX2 and APEX2 proteins were expressed in bacteria and purified. Approximately (∼) 1 µg of each protein was separated by SDS-PAGE, followed by Coomassie blue staining. M, molecular weight marker. (C) Confocal microscopy of VP1u-APEX2 entry. 1 × 10 6 UT7/Epo-S1 cells were incubated with 2 μM VP1u-APEX2 or APEX2 protein at 37°C for 2 h. The cells were then immunostained with α-Flag to visualize internalized proteins under a Leica STED confocal microscope. Scale bar = 10 μm. Nuclei were stained with DAPI (4’,6-diamidino-2-phenylindole). (D) Western blotting of APEX2-biotinylated proteins. 1 × 10 7 UT7/Epo-S1 cells were incubated with 2 μM VP1u-APEX2 or APEX2 protein at 37°C. After 2 h, APEX2-mediated biotinylation was then performed as described in the Materials and Methods and Figure S1 . Biotinylated host proteins were purified with streptavidin-conjugated magnetic beads. The supernatant was collected as the flow-through (FT), and the beads were further washed several times and eluted as the pull-down (PD). Both FT and PD samples were analyzed by SDS-PAGE and immunoblotting using Alexa Fluor 680-conjugated streptavidin. (E) Analysis of VP1u-APEX2-biotinylated/associated proteins using quantitative mass spectrometry (qMS). Three independent PD samples prepared from VP1u-APEX2 and APEX2 (control) treated cells were analyzed by on-bead digestion and qMS. MS data were processed and analyzed as described in the Materials and Methods. The bubble plot shows protein enrichment (log 2 fold change) in the VP1u-APEX2 group relative to the APEX control, with color indicating subcellular localization based on Gene Ontology (GO) annotation. TFRC denotes human transferrin receptor 1 (hTfR).

Article Snippet: Purified proteins: Recombinant hTfR ECD protein tagged with a His-tag at the C-terminus (#11020-H07H) and recombinant human ferritin heavy chain 1/FTH1 (#13217-HNAE) were purchased from SinoBiological (Paoli, PA).

Techniques: Residue, FLAG-tag, Purification, Bacteria, SDS Page, Staining, Molecular Weight, Marker, Confocal Microscopy, Incubation, Microscopy, Western Blot, Magnetic Beads, Mass Spectrometry, Control, Protein Enrichment

Journal: Journal of Cellular and Molecular Medicine

Article Title: Electroacupuncture Pretreatment Ameliorates Perioperative Neurocognitive Disorder in Aged Mice by Inhibiting Ferroptosis Through the SIRT1 / NRF2 / GPX4 Pathway

doi: 10.1111/jcmm.71021

Figure Lengend Snippet: SIRT1/NRF2/GPX4 pathway is involved in hippocampal ferroptosis in aged mice. (A) WB images and quantification analysis of SIRT1, NRF2 and GPX4 in the hippocampus of aged mice. (B) WB images and quantification analysis of SLC7A11, TFR1, IRP2 and ferritin in the hippocampus of aged mice ( n = 3 per group). (C) qRT‐PCR expression of SIRT1, NRF2, GPX4, SLC7A11, TFR1, IRP2 and ferritin mRNA in the hippocampus of aged mice ( n = 3 per group). Values are presented as mean ± SEM. ** p < 0.01 compared with the C group; # p < 0.05 and ## p < 0.01 compared with the M group; + p < 0.05 and ++ p < 0.01 and compared with the EX group.

Article Snippet: The membrane was then incubated overnight at 4°C with primary antibodies: SIRT1 (1:850; Lot‐19G10A10; BOSTER), NRF2 (1:1500; Cat#YT3189; Immunoway), iron regulatory protein 2 (IRP2) (1:3000; Cat#YN3307; Immunoway), transferrin receptor 1 (TFR1) (1:750; LotNo‐23BP65E1; BOSTER), GPX4 (1:1500; Cat#YN3047; Immunoway), ferritin (1:3000; Cat#YT1692; Immunoway) and SLC7A11 (1:2000; Cat#YT8130; Immunoway).

Techniques: Quantitative RT-PCR, Expressing