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