Journal: BMC Biology

Article Title: The phosphatase PPM1F, a negative regulator of integrin activity, is essential for embryonic development and controls tumor cell invasion

doi: 10.1186/s12915-025-02254-3

Figure Lengend Snippet: Increased integrin β1 activity, elevated cell adhesion, and migration defects of ppm1f-/- MEFs are reverted by re-expression of wildtype PPM1F. A PPM1F-/- MEFs were transduced with lentiviral particles encoding human wildtype PPM1F (hWT) or human PPM1F D360 A (hDA) in a bi-cistronic expression cassette with GFP. In addition, PPM1F-/- MEFs and PPM1F +/+ cells were transduced with a lentivirus encoding GFP alone. WCLs of sorted cells were analyzed by Western blotting with the indicated antibodies; as controls, WCLs of 293 T cells transfected with the empty vector (mock), GFP (GFP) or murine PPM1F (mWT) were loaded. B MEFs as in ( A ) were seeded onto 1 µg/ml FN III9-12 for 2 h. Samples were fixed and stained for talin (upper panel) or the active integrin β1 (lower panel) before analysis by confocal microscopy; scale bar: 20 µm. Insets show higher magnification of boxed areas; scale bar: 5 µm. Arrowheads point to active integrin β1 or talin enrichment. C MEFs as in ( A ) were kept in suspension for 45 min and incubated for 15 min with 10 µg/ml FN III9-12 (FN). Samples were stained for total (Hmb1-1) or active β1 integrin (9EG7) and analyzed by flow cytometry, ≥ 10 000 counts. The mean fluorescence intensity (MFI) ratio of active to total β1 integrin was calculated and normalized to the wildtype sample (= 1). Scatter blots represent mean ± SEM of 4 independent experiments; statistics was performed using one-way ANOVA and Bonferroni post-hoc test ( p *** < 0.001, ns = not significant). D MEFs were seeded in triplicates onto fibronectin-coated wells for 60 min and cell adhesion was quantified. Representative pictures from cells seeded on 10 µg/ml FN (left panel); scale bar: 150 µm. Scatter blots represent mean ± SEM of 5 independent experiments performed in technical triplicates each. Values were normalized to MEF wildtype cells (= 1). Statistics was performed using one-way ANOVA, followed by Bonferroni post-hoc test (** p < 0.01, * p < 0.05, ns = not significant). E MEFs were seeded onto indicated fibronectin concentrations for 45 min, fixed and stained with DAPI and Phalloidin-Cy5. Samples were imaged using confocal microscopy. Representative images from cells seeded onto 10 µg/ml FN are shown; scale bar: 10 µm (left panel). Quantification of cell spreading. Boxes and whiskers indicate median with 95% confidence intervals from 2 independent experiments; n ≥ 90 cells. Statistics was performed using one-way ANOVA, followed by Bonferroni post-hoc test (*** p < 0.001, ns = not significant) (right panel). F Serum starved MEFs were stimulated by addition of 10% FCS and cell migration was monitored every 30 min for 12 h using time-lapse microscopy. Cell tracks were evaluated for velocity, covered distance and directionality. Boxes and whiskers indicate median with 95% confidence intervals from 2 independent experiments ( n = 30); Statistics was performed as in ( E ); *** p < 0.001, * p < 0.05, ns = not significant. See also Additional_File2

Article Snippet: The following antibodies were used with the corresponding dilutions for western blot analysis (WB), immunofluorescence (IF), immunohistochemistry (IHC), immunoprecipitation (IP), or integrin activity assay (IA): α-Actinin (BM75.2, mouse anti-human, Abcam; 1:1000 WB), α 1 -integrin (TS2/7, mouse anti-human/anti-mouse, Abcam; 1:50 IF), α 2 -integrin (6 F1, mouse anti-human/anti-mouse, DSHB; 1:60 IF), α 3 -integrin (P1B5, mouse anti-human/anti-mouse, DSHB; 1:60 IF), α 5 -integrin (BIIG2, rat anti-human/anti-mouse, DSHB; 1:10 IF), α v -integrin (PE-P2 W7 mouse anti-human/anti-mouse, sc-9969; IF 1:300), β 1 -integrin (HMβ1-1, armenian hamster anti-mouse, Bio Legend; 1:300 IF; AIIB2, rat anti-human/anti-mouse, DSHB; 1:600 IF, IA; M-106, rabbit anti-mouse/anti-human, Santa Cruz; 1:500 WB; D2E5, rabbit anti-human, Cell Signaling; 1:1000 WB), human β 1 -integrin (P5D2, mouse anti-human, DSHB, 2.5 μg IP; 9EG7, rat anti- human, DSHB 2.5 μg IP; AIIB2, rat anti-human, DSHB; 2.5 μg IP), β 3 -integrin (2 C9.G3, arm. hamster anti-mouse, eBioscience; 1:300 IF; PM6/13, mouse anti-human, Abcam; 1:100 IF), β 5 -integrin (KN-52, mouse anti-mouse/human, eBioscience; IF 1:300), Focal adhesion kinase (FAK) (77, mouse anti-human, BD; 1:250 WB), integrin-linked kinase (ILK) (EP1593Y, rabbit anti-human, Epitomics; 1:800 WB), Kindlin-2 (3 A3, mouse anti-human, Millipore; 1:200 WB, 1:250 IF), Laminin (ab11575, rabbit anti-mouse, Abcam; 1:300 IHC), Nestin (rat-401, anti-mouse, Millipore; IHC 1:200), Paxillin (5H11, mouse monoclonal, Thermo Scientific; 1:1000 WB), hPPM1F (17,020–1-AP, rabbit anti-human, Protein-Tech; 1:1000 WB), mPPM1F (#1147, rabbit anti-mouse PPM1F; generated at the central animal care facility; University of Konstanz; 1:200 WB; see Additional File2: Fig. S2), FilaminA (EP2405Y, IgG, rabbit anti-human, Epitomics; 1:125.000 WB), Tubulin (E7, IgG1, mouse anti-human, DSHB; 1:1000), Talin (8 d4, mouse anti-human, Thermo Scientific; 1:800 WB, 1:40 IF), Vinculin (hVIN-1, mouse anti-human, Sigma; 1:2000 WB, 1:200 IF), Zyxin (Zol301, mouse anti-human, Abcam; 1:1000 WB), Dylight488-conjugated goat anti-mouse IgG (Jackson; 1:200), Cy3-conjugated goat anti-rabbit IgG (Jackson; 1:200), Cy3-conjugated goat anti-mouse IgG (Jackson; 1:200), Cy5-conjugated goat anti-mouse IgG (Jackson; 1:200), RhodamineRed-conjugated goat anti-rat IgG (Jackson; 1:200), RhodamineRed-conjugated goat anti-Armenian Hamster IgG (Jackson; 1:200), HRP-conjugated goat anti-mouse IgG (Jackson; WB 1:10 000), HRP-conjugated goat anti-rat IgG (Santa Cruz; 1:250), HRP-conjugated goat anti-rabbit IgG (Jackson; WB 1:3000), unspecific control IgG (anti-mouse, 96/1, generated at the Tierforschungsanlage; University of Konstanz; anti-rat, MJ7/18 Endoglin, DSHB).

Techniques: Activity Assay, Migration, Expressing, Transduction, Western Blot, Transfection, Plasmid Preparation, Staining, Confocal Microscopy, Suspension, Incubation, Flow Cytometry, Fluorescence, Time-lapse Microscopy

Journal: BMC Biology

Article Title: The phosphatase PPM1F, a negative regulator of integrin activity, is essential for embryonic development and controls tumor cell invasion

doi: 10.1186/s12915-025-02254-3

Figure Lengend Snippet: PPM1F contributes to the invasive phenotype of tumor cells. A WCLs from indicated cancer cell lines were analyzed by Western blotting with α-human PPM1F or α-integrin β1 antibodies. α-Tubulin antibody was used as loading control. B , C Indicated serum-starved cancer cells were seeded on top of a Matrigel basement membrane (30 µg/100 µl) in Boyden chamber cell invasion assays using 20% FCS as stimulus or 2% BSA to evaluate random invasion activity. NIH3 T3 cells served as non-invasive control cells. Representative pictures of the lower porous membrane surface (20x) are shown in (B); scale bar: 50 µm. Crystal violet-stained cells can be distinguished from the 8 µm membrane pores. Cells were evaluated for invasion after 24 h by dye elution with 10% acetic acid and absorbance measurement at 590 nm. Graph in ( C ) shows quantified means ± SEM from three independent experiments. Statistics was performed using one-way ANOVA and Bonferroni post-hoc test ( p *** < 0.001, p ** < 0.01, ns = not significant). D MCF-7 cells were stably transduced with lentiviral particles harboring a bicistronic GFP and hPPM1F wildtype or hPPM1F D360 A expression cassette and single-cell sorted via flow cytometry for GFP positive cells to obtain a mixed population of PPM1F-overexpressing MCF-7 cells (PPM1F + + and PPM1F D360 A + +). WCL of the wildtype and modified cell lines were analyzed by Western blotting with indicated antibodies. α-tubulin antibody (lowest panel) served as loading control. E Serum-starved cells from ( D ) were seeded on top of a Matrigel base (30 µg/100 µl) in Boyden chambers. Cell invasion was stimulated by addition of 20% FCS or 2% BSA to the lower chamber. Representative pictures of the lower porous membrane surface (20x) are shown; scale bar: 50 µm. Crystal violet-stained cells can be distinguished from the 8 µm membrane pores. Invasion was quantified by dye elution. Graph (right) shows means ± SEM from four independent experiments performed in triplicate. Statistics as in ( C )

Article Snippet: The following antibodies were used with the corresponding dilutions for western blot analysis (WB), immunofluorescence (IF), immunohistochemistry (IHC), immunoprecipitation (IP), or integrin activity assay (IA): α-Actinin (BM75.2, mouse anti-human, Abcam; 1:1000 WB), α 1 -integrin (TS2/7, mouse anti-human/anti-mouse, Abcam; 1:50 IF), α 2 -integrin (6 F1, mouse anti-human/anti-mouse, DSHB; 1:60 IF), α 3 -integrin (P1B5, mouse anti-human/anti-mouse, DSHB; 1:60 IF), α 5 -integrin (BIIG2, rat anti-human/anti-mouse, DSHB; 1:10 IF), α v -integrin (PE-P2 W7 mouse anti-human/anti-mouse, sc-9969; IF 1:300), β 1 -integrin (HMβ1-1, armenian hamster anti-mouse, Bio Legend; 1:300 IF; AIIB2, rat anti-human/anti-mouse, DSHB; 1:600 IF, IA; M-106, rabbit anti-mouse/anti-human, Santa Cruz; 1:500 WB; D2E5, rabbit anti-human, Cell Signaling; 1:1000 WB), human β 1 -integrin (P5D2, mouse anti-human, DSHB, 2.5 μg IP; 9EG7, rat anti- human, DSHB 2.5 μg IP; AIIB2, rat anti-human, DSHB; 2.5 μg IP), β 3 -integrin (2 C9.G3, arm. hamster anti-mouse, eBioscience; 1:300 IF; PM6/13, mouse anti-human, Abcam; 1:100 IF), β 5 -integrin (KN-52, mouse anti-mouse/human, eBioscience; IF 1:300), Focal adhesion kinase (FAK) (77, mouse anti-human, BD; 1:250 WB), integrin-linked kinase (ILK) (EP1593Y, rabbit anti-human, Epitomics; 1:800 WB), Kindlin-2 (3 A3, mouse anti-human, Millipore; 1:200 WB, 1:250 IF), Laminin (ab11575, rabbit anti-mouse, Abcam; 1:300 IHC), Nestin (rat-401, anti-mouse, Millipore; IHC 1:200), Paxillin (5H11, mouse monoclonal, Thermo Scientific; 1:1000 WB), hPPM1F (17,020–1-AP, rabbit anti-human, Protein-Tech; 1:1000 WB), mPPM1F (#1147, rabbit anti-mouse PPM1F; generated at the central animal care facility; University of Konstanz; 1:200 WB; see Additional File2: Fig. S2), FilaminA (EP2405Y, IgG, rabbit anti-human, Epitomics; 1:125.000 WB), Tubulin (E7, IgG1, mouse anti-human, DSHB; 1:1000), Talin (8 d4, mouse anti-human, Thermo Scientific; 1:800 WB, 1:40 IF), Vinculin (hVIN-1, mouse anti-human, Sigma; 1:2000 WB, 1:200 IF), Zyxin (Zol301, mouse anti-human, Abcam; 1:1000 WB), Dylight488-conjugated goat anti-mouse IgG (Jackson; 1:200), Cy3-conjugated goat anti-rabbit IgG (Jackson; 1:200), Cy3-conjugated goat anti-mouse IgG (Jackson; 1:200), Cy5-conjugated goat anti-mouse IgG (Jackson; 1:200), RhodamineRed-conjugated goat anti-rat IgG (Jackson; 1:200), RhodamineRed-conjugated goat anti-Armenian Hamster IgG (Jackson; 1:200), HRP-conjugated goat anti-mouse IgG (Jackson; WB 1:10 000), HRP-conjugated goat anti-rat IgG (Santa Cruz; 1:250), HRP-conjugated goat anti-rabbit IgG (Jackson; WB 1:3000), unspecific control IgG (anti-mouse, 96/1, generated at the Tierforschungsanlage; University of Konstanz; anti-rat, MJ7/18 Endoglin, DSHB).

Techniques: Western Blot, Control, Membrane, Activity Assay, Staining, Stable Transfection, Transduction, Expressing, Flow Cytometry, Modification

Journal: BMC Biology

Article Title: The phosphatase PPM1F, a negative regulator of integrin activity, is essential for embryonic development and controls tumor cell invasion

doi: 10.1186/s12915-025-02254-3

Figure Lengend Snippet: Genetic deletion of PPM1F in tumor cells diminishes matrix invasion and integrin phosphorylation. A WCLs from A172 wildtype cells and two clonal PPM1F KO cell lines (1 and 2) were analyzed by Western blotting using the indicated antibodies. α-Tubulin antibody was used as loading control. B Serum starved A172 wildtype cells and PPM1F KO cell lines (clone 1 and clone 2) were seeded in triplicate onto fibronectin-, vitronectin-, or 2% BSA-coated wells for 60 min either in presence of 50 µM cilengitide or DMSO as control. Wells were washed and adherent cells were stained with crystal violet. Representative pictures are shown; scale bar: 150 µm. C Adherent crystal violett stained cells from ( B ) were quantified by dye elution. Graph depicts individual values as well as mean ± SEM of 4 independent experiments performed in technical triplicates. Statistics was performed using one-way ANOVA, followed by Bonferroni post-hoc test (*** p < 0.001; ** p < 0.01; p * < 0.05; ns = not significant) and shown for the PPM1F knock-out clones in relation to the A172 wildtype cells. D Serum-starved cells as in ( C ) were seeded on top of a Matrigel base (30 µg/100 µl) in Boyden chambers and cell invasion was stimulated by addition of 20% FCS or 2% BSA to the lower chamber. Cells were evaluated for invasion after 24 h and representative pictures of the lower porous membrane surface (20x) are shown; scale bar: 50 µm. Crystal violet-stained cells can be distinguished from the 8 µm membrane pores (left). Invasion assays were quantified by dye elution. Graph depicts individual values as well as means ± SEM from four independent experiments performed in triplicate. Statistics as in ( C ). See also Additional_File4 and Additional_File5

Article Snippet: The following antibodies were used with the corresponding dilutions for western blot analysis (WB), immunofluorescence (IF), immunohistochemistry (IHC), immunoprecipitation (IP), or integrin activity assay (IA): α-Actinin (BM75.2, mouse anti-human, Abcam; 1:1000 WB), α 1 -integrin (TS2/7, mouse anti-human/anti-mouse, Abcam; 1:50 IF), α 2 -integrin (6 F1, mouse anti-human/anti-mouse, DSHB; 1:60 IF), α 3 -integrin (P1B5, mouse anti-human/anti-mouse, DSHB; 1:60 IF), α 5 -integrin (BIIG2, rat anti-human/anti-mouse, DSHB; 1:10 IF), α v -integrin (PE-P2 W7 mouse anti-human/anti-mouse, sc-9969; IF 1:300), β 1 -integrin (HMβ1-1, armenian hamster anti-mouse, Bio Legend; 1:300 IF; AIIB2, rat anti-human/anti-mouse, DSHB; 1:600 IF, IA; M-106, rabbit anti-mouse/anti-human, Santa Cruz; 1:500 WB; D2E5, rabbit anti-human, Cell Signaling; 1:1000 WB), human β 1 -integrin (P5D2, mouse anti-human, DSHB, 2.5 μg IP; 9EG7, rat anti- human, DSHB 2.5 μg IP; AIIB2, rat anti-human, DSHB; 2.5 μg IP), β 3 -integrin (2 C9.G3, arm. hamster anti-mouse, eBioscience; 1:300 IF; PM6/13, mouse anti-human, Abcam; 1:100 IF), β 5 -integrin (KN-52, mouse anti-mouse/human, eBioscience; IF 1:300), Focal adhesion kinase (FAK) (77, mouse anti-human, BD; 1:250 WB), integrin-linked kinase (ILK) (EP1593Y, rabbit anti-human, Epitomics; 1:800 WB), Kindlin-2 (3 A3, mouse anti-human, Millipore; 1:200 WB, 1:250 IF), Laminin (ab11575, rabbit anti-mouse, Abcam; 1:300 IHC), Nestin (rat-401, anti-mouse, Millipore; IHC 1:200), Paxillin (5H11, mouse monoclonal, Thermo Scientific; 1:1000 WB), hPPM1F (17,020–1-AP, rabbit anti-human, Protein-Tech; 1:1000 WB), mPPM1F (#1147, rabbit anti-mouse PPM1F; generated at the central animal care facility; University of Konstanz; 1:200 WB; see Additional File2: Fig. S2), FilaminA (EP2405Y, IgG, rabbit anti-human, Epitomics; 1:125.000 WB), Tubulin (E7, IgG1, mouse anti-human, DSHB; 1:1000), Talin (8 d4, mouse anti-human, Thermo Scientific; 1:800 WB, 1:40 IF), Vinculin (hVIN-1, mouse anti-human, Sigma; 1:2000 WB, 1:200 IF), Zyxin (Zol301, mouse anti-human, Abcam; 1:1000 WB), Dylight488-conjugated goat anti-mouse IgG (Jackson; 1:200), Cy3-conjugated goat anti-rabbit IgG (Jackson; 1:200), Cy3-conjugated goat anti-mouse IgG (Jackson; 1:200), Cy5-conjugated goat anti-mouse IgG (Jackson; 1:200), RhodamineRed-conjugated goat anti-rat IgG (Jackson; 1:200), RhodamineRed-conjugated goat anti-Armenian Hamster IgG (Jackson; 1:200), HRP-conjugated goat anti-mouse IgG (Jackson; WB 1:10 000), HRP-conjugated goat anti-rat IgG (Santa Cruz; 1:250), HRP-conjugated goat anti-rabbit IgG (Jackson; WB 1:3000), unspecific control IgG (anti-mouse, 96/1, generated at the Tierforschungsanlage; University of Konstanz; anti-rat, MJ7/18 Endoglin, DSHB).

Techniques: Phospho-proteomics, Western Blot, Control, Staining, Knock-Out, Clone Assay, Membrane

Journal: BMC Biology

Article Title: The phosphatase PPM1F, a negative regulator of integrin activity, is essential for embryonic development and controls tumor cell invasion

doi: 10.1186/s12915-025-02254-3

Figure Lengend Snippet: Increased integrin-based cell adhesion in PPM1F-deficient cells prohibits cell spreading despite elevated PAK activity. A Serum-starved A172 wildtype, sgRNA control and PPM1F KO cells were seeded onto 2 µg/ml FN III9-12 for 45 min and WCLs were subjected to Western blotting with indicated antibodies (left panel). Graphs (right panel) show densitometric quantification of band intensities from pThr402PAK2 versus PAK antibody signal for the indicated samples from 5 independent experiments; wildtype was set to 1. Statistics were performed using one-way ANOVA, followed by Bonferroni post-hoc test (* p < 0.05, ns = not significant). B Serum-starved A172 wildtype and PPM1F KO cells were seeded onto 2 µg/ml FN III9-12 for 1.5 h, fixed and F-actin was stained. Samples were imaged using confocal microscopy. Representative pictures are shown; scale bar: 20 µm. C Cells as in ( B ) were seeded for 2 h on surfaces coated with 10 µg/ml fibronectin or poly-L-lysine, before fixation, F-actin staining and analysis by confocal microscopy; scale bar: 10 µm. D Spreading assays were performed with serum-starved A172 wildtype and PPM1F KO cells re-expressing mKate2 or re-expressing PPM1F-mKate2 cells, pre-treated with 5 µM DMSO or FRAX597 (PAK1-3 inhibitor) for 45 min in suspension before seeding onto 2 µg/ml FN III9-12 for 1.5 h. Cells were fixed, stained for F-actin and the covered area was quantified in ImageJ. Boxes and whiskers indicate median with 95% confidence intervals from two independent experiments; n ≥ 30 cells; dots indicate outliers. Statistics was performed using one-way ANOVA, followed by post-hoc Bonferroni test, (*** p < 0.001, ns = not significant). E Serum-starved cells as in ( D ) were pre-treated with 5 µM DMSO or FRAX597 (PAK1-3 inhibitor) for 45 min in suspension before seeded onto 2 µg/ml FN III9-12 for 1.5 h. Cells were fixed and stained for active integrin β1. Cells were imaged by confocal microscopy. Representative pictures are shown; scale bar: 10 µm. See also Additional_File6 and Additional_File7

Article Snippet: The following antibodies were used with the corresponding dilutions for western blot analysis (WB), immunofluorescence (IF), immunohistochemistry (IHC), immunoprecipitation (IP), or integrin activity assay (IA): α-Actinin (BM75.2, mouse anti-human, Abcam; 1:1000 WB), α 1 -integrin (TS2/7, mouse anti-human/anti-mouse, Abcam; 1:50 IF), α 2 -integrin (6 F1, mouse anti-human/anti-mouse, DSHB; 1:60 IF), α 3 -integrin (P1B5, mouse anti-human/anti-mouse, DSHB; 1:60 IF), α 5 -integrin (BIIG2, rat anti-human/anti-mouse, DSHB; 1:10 IF), α v -integrin (PE-P2 W7 mouse anti-human/anti-mouse, sc-9969; IF 1:300), β 1 -integrin (HMβ1-1, armenian hamster anti-mouse, Bio Legend; 1:300 IF; AIIB2, rat anti-human/anti-mouse, DSHB; 1:600 IF, IA; M-106, rabbit anti-mouse/anti-human, Santa Cruz; 1:500 WB; D2E5, rabbit anti-human, Cell Signaling; 1:1000 WB), human β 1 -integrin (P5D2, mouse anti-human, DSHB, 2.5 μg IP; 9EG7, rat anti- human, DSHB 2.5 μg IP; AIIB2, rat anti-human, DSHB; 2.5 μg IP), β 3 -integrin (2 C9.G3, arm. hamster anti-mouse, eBioscience; 1:300 IF; PM6/13, mouse anti-human, Abcam; 1:100 IF), β 5 -integrin (KN-52, mouse anti-mouse/human, eBioscience; IF 1:300), Focal adhesion kinase (FAK) (77, mouse anti-human, BD; 1:250 WB), integrin-linked kinase (ILK) (EP1593Y, rabbit anti-human, Epitomics; 1:800 WB), Kindlin-2 (3 A3, mouse anti-human, Millipore; 1:200 WB, 1:250 IF), Laminin (ab11575, rabbit anti-mouse, Abcam; 1:300 IHC), Nestin (rat-401, anti-mouse, Millipore; IHC 1:200), Paxillin (5H11, mouse monoclonal, Thermo Scientific; 1:1000 WB), hPPM1F (17,020–1-AP, rabbit anti-human, Protein-Tech; 1:1000 WB), mPPM1F (#1147, rabbit anti-mouse PPM1F; generated at the central animal care facility; University of Konstanz; 1:200 WB; see Additional File2: Fig. S2), FilaminA (EP2405Y, IgG, rabbit anti-human, Epitomics; 1:125.000 WB), Tubulin (E7, IgG1, mouse anti-human, DSHB; 1:1000), Talin (8 d4, mouse anti-human, Thermo Scientific; 1:800 WB, 1:40 IF), Vinculin (hVIN-1, mouse anti-human, Sigma; 1:2000 WB, 1:200 IF), Zyxin (Zol301, mouse anti-human, Abcam; 1:1000 WB), Dylight488-conjugated goat anti-mouse IgG (Jackson; 1:200), Cy3-conjugated goat anti-rabbit IgG (Jackson; 1:200), Cy3-conjugated goat anti-mouse IgG (Jackson; 1:200), Cy5-conjugated goat anti-mouse IgG (Jackson; 1:200), RhodamineRed-conjugated goat anti-rat IgG (Jackson; 1:200), RhodamineRed-conjugated goat anti-Armenian Hamster IgG (Jackson; 1:200), HRP-conjugated goat anti-mouse IgG (Jackson; WB 1:10 000), HRP-conjugated goat anti-rat IgG (Santa Cruz; 1:250), HRP-conjugated goat anti-rabbit IgG (Jackson; WB 1:3000), unspecific control IgG (anti-mouse, 96/1, generated at the Tierforschungsanlage; University of Konstanz; anti-rat, MJ7/18 Endoglin, DSHB).

Techniques: Activity Assay, Control, Western Blot, Staining, Confocal Microscopy, Expressing, Suspension

Journal: bioRxiv

Article Title: Binding of inhibitory checkpoints to CD18 in cis hinders anti-cancer immune responses

doi: 10.1101/2025.09.10.675342

Figure Lengend Snippet: ( A and B ) Immunoprecipitation followed by mass spectrometry of SIRPα-associated proteins. ( A ) Schematic representation of assay. ( B ) Plasma membrane-associated proteins found in SIRPα immunoprecipitates from WT BMDMs, but not from SIRPα KO BMDMs. c , Co-immunoprecipitation assay of SIRPα, CD18 and CD11b in WT and SIRPα KO BMDMs. IP, immunoprecipitation. Abs, antibodies. ( D to F ) FRET assays. ( D ) Schematic representation of FRET assay in HEK293T cells. ( E and F ) Representative confocal microscopy images ( E ) and compiled data ( F ) of FRET assays with donor-labeled SIRPα, acceptor-labeled CD18 and unlabeled CD11b in the presence of control (Ctrl) IgG, CD18 mAb GAME-46 or CD11b mAb 5C6. Yellow to purple spectrum denotes strong to weak FRET. DIC, differential interference contrast. Scale bars, 5 μm. ( G and H ) LUV-FRET assay. ( G ) Schematic representation of LUV-FRET assay. ( H ), Time-course of donor-labeled SIRPα fluorescence intensity after addition of acceptor-labeled CD18 or CD11b, monitored with a real-time plate reader. All data are means ± s.e.m. ns, not significant, **** p < 0.0001. Results in ( C , E and H ) are representative of 3 independent experiments. Results in ( B and F ) are pooled from a total of 3 independent experiments. Each symbol in ( F ) represents one cell.

Article Snippet: Human cDNAs for SIRPα version (V) 1 (Cat: HG11612-UT), PD-1 (Cat: HG10377-M), LILRB1 (Cat: HG16014-UT), 2B4 (Cat: HG10042-NF), CD18 (Cat: HG10970-UT) and CD11b (Cat: HG10494-UT) were obtained from Sino Biological (Beijing, China).

Techniques: Immunoprecipitation, Mass Spectrometry, Clinical Proteomics, Membrane, Co-Immunoprecipitation Assay, Confocal Microscopy, Labeling, Control, Fluorescence

Journal: bioRxiv

Article Title: Binding of inhibitory checkpoints to CD18 in cis hinders anti-cancer immune responses

doi: 10.1101/2025.09.10.675342

Figure Lengend Snippet: ( A and B ) FRET assays with SIRPα and SIRPβ1a. ( A ) A schematic representation of SIRPα and SIRPβ1a, with their 1 IgV domain and 2 IgC domains, is depicted. ( B ) Compiled data of 3 independent experiments using donor-labeled SIRPα or SIRPβ1a, acceptor-labeled CD18 and unlabeled CD11b, as done for , D to F. ( C and D ) FRET assays using SIRPα IgV domain. ( C ) A schematic representation of a SIRPα variant having only the IgV domain is shown. ( D ) Compiled data of 3 independent experiments using donor-labeled SIRPα IgV, acceptor-labeled CD18 and unlabeled CD11b, as done for , D to F. ( E - H ) FRET assays using SIRPα variants carrying non-conserved residues from SIRPβ1a. ( E and G ) Schematic representations of SIRPα variants. ( F and H ) Compiled data from 3 independent experiments using donor-labeled SIRPα variants, acceptor-labeled CD18 and unlabeled CD11b, as done for , D to F. ( I to K ) Proximity ligation assay (PLA) of SIRPα and CD18 in BMDMs expressing or not the indicated SIRPα variants. (I) Flow cytometry analyses of SIRPα expression. ( J and K ) Representative confocal microscopy images ( J ) and compiled data from 3 independent experiments ( K ) of PLA for SIRPα and CD18. Scale bar, 10 μm. All data are means ± s.e.m. ns, not significant, **** p < 0.0001. Results in ( I and J ) are representative of 3 independent experiments. Results in ( B , D , F , H and K ) are pooled from 3 independent experiments. Each symbol in ( B , D , F , H and K ) represents one cell or mouse.

Article Snippet: Human cDNAs for SIRPα version (V) 1 (Cat: HG11612-UT), PD-1 (Cat: HG10377-M), LILRB1 (Cat: HG16014-UT), 2B4 (Cat: HG10042-NF), CD18 (Cat: HG10970-UT) and CD11b (Cat: HG10494-UT) were obtained from Sino Biological (Beijing, China).

Techniques: Labeling, Variant Assay, Proximity Ligation Assay, Expressing, Flow Cytometry, Confocal Microscopy

Journal: bioRxiv

Article Title: Binding of inhibitory checkpoints to CD18 in cis hinders anti-cancer immune responses

doi: 10.1101/2025.09.10.675342

Figure Lengend Snippet: ( A to C ) The impact of SIRPα variants defective in CD18-binding, CD47-binding or phosphatase signaling, alone or in combination, expressed in BMDMs, was analyzed. ( A ) Schematic depictions of SIRPα variants, as was done for . SIRPα R91T carried an arginine (R)-to-threonine (T) mutation at position 91 (shown by blue star), which abolished CD18-binding. ( B ) Phagocytosis assays of IgG-opsonized L1210 cells by BMDMs, as was done for . ( C ) Efficiency of phagocytosis inhibition was calculated as for , using values from . ( D and E ) Representative flow cytometry profiles ( D ) and compiled data from 3 independent experiments ( E ) of ICAM-1-binding using SIRPα KO BMDMs expressing WT SIRPα or SIRPα R91T BMDMs, in the presence or absence of FcR triggering using mouse IgG2a. ( F and G ) The impact of a SIRPα variant carrying the isoleucine-to-glycine 332 (I332G) mutation, expressed in SIRPα KO BMDMs, was analyzed. (F) Flow cytometry analyses of CD11b expression. ( G ) Compiled data from 3 independent phagocytosis assays, assessed by microscopy. ( H ) FRET assays of donor-labeled SIRPα, acceptor-labeled CD18 and unlabeled CD11b in the presence of WT CD11b or CD11b I332G , as was done for , D to F. ( I ) FRET assays of donor-labeled human SIRPα version (V) 1 or V2 with acceptor-labeled human CD18 and unlabeled human CD11b, in the presence of Ctrl IgG, human CD18 mAbs CBR LFA1/2 or TS1/18, as was done for , D to F. ( J ) Phagocytosis of human lymphoma cells Raji, which were opsonized with CD20 mAbs, by human peripheral blood monocyte (PBMC)-derived macrophages, in the presence of the indicated mAbs, was assessed by microscopy. All data are means ± s.e.m. ns, not significant; * p < 0.05, ** p < 0.01 and **** p < 0.0001. Results in ( D and F ) are representative of 3 independent experiments. Results in ( B , C , E and G to J ) are pooled from 3 independent experiments. Each symbol in ( B , E and G to J ) represents one cell, mouse or healthy donor.

Article Snippet: Human cDNAs for SIRPα version (V) 1 (Cat: HG11612-UT), PD-1 (Cat: HG10377-M), LILRB1 (Cat: HG16014-UT), 2B4 (Cat: HG10042-NF), CD18 (Cat: HG10970-UT) and CD11b (Cat: HG10494-UT) were obtained from Sino Biological (Beijing, China).

Techniques: Binding Assay, Mutagenesis, Inhibition, Flow Cytometry, Expressing, Variant Assay, Microscopy, Labeling, Derivative Assay

Journal: bioRxiv

Article Title: Binding of inhibitory checkpoints to CD18 in cis hinders anti-cancer immune responses

doi: 10.1101/2025.09.10.675342

Figure Lengend Snippet: ( A ) FRET assays of donor-labeled mouse SIRPα with acceptor-labeled mouse CD18 and unlabeled mouse CD11b, in the presence of Fc-silent mouse SIRPα mAbs, as was done for , D to F. ( B ) Binding of a soluble CD47-Fc fusion protein to EL-4 cells, expressing or not expressing mouse SIRPα, was studied by flow cytometry. ( C to K ) Generation and impact of bispecific antibody (BsAb) against mouse SIRPα. ( C ) Schematic representation of Fc-silent BsAb combining one arm of mAb #17 with one arm of mAb #27, using the “knob-into-hole” technology. Phagocytosis of IgG-opsonized L1210 cells ( D ) and EL-4 cells ( E ) by WT BMDMs, in the presence of mAbs, was assessed by a microscopy assays. ( F to K ) Schematic depictions of the assays are shown in (F and I). RAG-1 KO mice injected subcutaneously with Tac + L1210 cells ( G and H ), or C57BL/6J mice injected subcutaneously with Tac + EL-4 cells ( J and K ), were treated by intraperitoneal injection of Fc-silent mAbs, alongside Tac mAb 7G7 for opsonization. Tumor volume was measured using a caliper ( G and J ) and survival was recorded ( H and K ). ( L ) FRET assays of donor-labeled human SIRPα V1 or V2 with acceptor-labeled human CD18 and unlabeled human CD11b in the presence of Fc-silent Ctrl IgG and human SIRPα mAbs KWAR23, 40A, 50A, or 18D5, as was done for , D to F. The mAbs were rendered Fc-silent by the LALAPG mutation. ( M ) Phagocytosis of IgG-opsonized Raji cells by human macrophages in the presence of Fc-silent Ctrl IgG and SIRPα mAbs KWAR23, 40A, 50A, or 18D5, was assayed as for . ( N ) FRET assays of donor-labeled human 2B4 (SLAMF4), PD-1 or LILRB1 with acceptor-labeled human CD18, in the presence of Ctrl IgG or human CD18 mAb were done as for , D to F. All data are means ± s.e.m. ns, not significant; * p < 0.05, ** p < 0.01, *** p < 0.001 and **** p < 0.0001. Results are pooled from a total of two ( H and K ), three ( A , D , E , G , J , L and N ) or five ( B and M ) independent experiments. Each symbol in ( A , D , E and L to N ) represents one healthy donor, cell or mouse.

Article Snippet: Human cDNAs for SIRPα version (V) 1 (Cat: HG11612-UT), PD-1 (Cat: HG10377-M), LILRB1 (Cat: HG16014-UT), 2B4 (Cat: HG10042-NF), CD18 (Cat: HG10970-UT) and CD11b (Cat: HG10494-UT) were obtained from Sino Biological (Beijing, China).

Techniques: Labeling, Binding Assay, Expressing, Flow Cytometry, Microscopy, Injection, Mutagenesis

Journal: Journal of neuroinflammation

Article Title: Autophagy defects at weaning impair complement-dependent synaptic pruning and induce behavior deficits.

doi: 10.1186/s12974-024-03235-z

Figure Lengend Snippet: Fig. 9 Autophagy deficiency at weaning period impairs complement-mediated synaptic pruning by microglia. A Schematic illustration of complement-mediated synaptic pruning by microglia. B, C 3-MA treatment led to the reduced mRNA expression of C4 (B) and reduced protein level of C1q and C3b (C) in the hippocampus. D Schematic illustration of the primary neuron experiment. E 3-MA treatment increased the expression of P62, while decreased the expression of Beclin, C1q and C3b. The expression levels of PSD95 and SYN remained unchanged. F The protein expression levels of C1q, C3b and CR3 in synaptic fraction were significantly reduced in the brain of 3-MA rats. G Quantitative analysis revealed a decrease in the content of C1q, C3b and CR3 in synaptic fraction. *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001. Data are presented as mean ± SEM

Article Snippet: The membranes were blocked with 5% non-fat milk for 1 h, and exposed to primary antibodies against Iba1 (GeneTex, GTX100042), PSD95 (Cell Signaling Technology, 36233S), SYN (Abcam, ab8049), Beclin (Proteintech, 66665-1-1g), P62 (Proteintech, 18420-1-AP), LC3 (Proteintech, 14600-1- AP), C1qa (Abcam, EPR14634), CR3 (Boster, BA0590), C3b (Abcam,2B10B9B2), Actin (Boster, MA1000) and GAPDH (Boster, M00227) at a 1:1000 dilution overnight at 4 °C.

Techniques: Expressing