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: Human PPM1F RNA-sequencing tissue data (reported as mean protein-coding transcripts per million (pTPM)) were purchased from the Human Protein Atlas portal (HPA transcriptomic study) ( https://www.proteinatlas.org/ENSG00000100034-PPM1F ) [ , ], the Genotype-Tissue Expression project (GTEX; https://www.gtexportal.org/home/gene/ENSG00000100034 ), the Functional Annotation of Mammalian Genome 5 (FANTOM5) project ( https://fantom.gsc.riken.jp/5/ ) [ , ] and the BioGPS Gene Atlas ( http://biogps.org/#goto=genereport&id=9647 , Dataset U133 A, gcrma) [ ].
Techniques: Activity Assay, Migration, Expressing, Transduction, Western Blot, Transfection, Plasmid Preparation, Staining, Confocal Microscopy, Suspension, Incubation, Flow Cytometry, Fluorescence, Time-lapse Microscopy