Journal: The Journal of Biological Chemistry
Article Title: Abnormal regulation of membrane-less organelles contributes to profilin1-associated ALS
doi: 10.1016/j.jbc.2025.110259
Figure Lengend Snippet: PFN1 deficiency accelerates Stress granule assembly in response to stress . A , HEK 293 cells were transfected with the indicated siRNAs, and stressed with arsenite (500 μM, 30 min). Subsequently, the cells were fixed, and subjected to immunofluorescence staining using an antibody against G3BP1 (Stress granule), DAPI was used for nuclear staining. The stained cells were visualized by confocal microscopy. Scale bar, 10 μm. B , quantification of the integrated fluorescence intensity of G3BP1 in the dense phase (condensates) and dilute phase (surrounding nucleoplasm) of cells in (A). C , quantification of the Stress granule size in ( A ). Mean ± SD., ∗∗, p < 0.01, p values were determined by unpaired Student’s t test. D , quantification of the Stress granule number in ( A ). Mean ± SD., ns, not significantly different, p values were determined by unpaired Student’s t test. E and F , HEK 293 cells were transfected with the indicated siRNAs and stressed with arsenite (500 μM, 30 min). Subsequently, the cells were fixed and subjected to immunofluorescence staining using antibodies against G3BP1 and TIA1(Stress granule), DAPI was used for nuclear staining. The stained cells were visualized by confocal microscopy. Scale bar, 5 μm. The fluorescence intensities were quantified on the corresponding lines. G-J , HEK 293 cells were transfected with the indicated siRNAs for 48 h, and then the cells were treated with either DMSO or 500 μM arsenite for 30 min. Cell lysates were subjected to droplet co-sedimentation assays and then subjected to immunoblotting using anti-G3BP1, PFN1, and GAPDH antibodies. The data are presented as means ± SD from three independent biological replicates. ns, not significantly different, ∗∗, p < 0.01, p values were determined by unpaired Student’s t test. K , HEK 293 cells stably expressing EGFP-G3BP1 were transfected with indicated siRNAs. After 48 h, cells were treated with 500 μM arsenite for 30 min to induce Stress granules, and then subjected to FRAP analysis. Scale bars: 5 μm. L , FRAP recovery curves (quantification data) of experiments in ( K ). n = 3. M , HEK 293 cells were transfected with the indicated siRNAs for 48 h, and then the cells were treated with 500 μM arsenite for 30 min. Cell lysates were subjected to TritonX-100-soluble and insoluble protein fractionation and subjected to immunoblotting using anti-G3BP1, PFN1, and GAPDH antibodies (n = 3 biological replicates).
Article Snippet: The following primary antibodies were used: anti-PFN1 antibody (Proteintech, 67,390-1-lg), anti-Coilin antibody (Proteintech, 10967-1-AP), anti-G3BP1 antibody (Proteintech, 13057-2-AP), anti-GFP antibody (Santa Cruz Biotechnology, sc-9996), anti-eIF2α (Cell Signaling Technology, 9722), anti-Phospho-eIF2α (Cell Signaling Technology, 9721), anti-puromycin antibody (Abclonal, A23031), and anti-GAPDH antibody (Proteintech, 60004-1-Ig).
Techniques: Transfection, Immunofluorescence, Staining, Confocal Microscopy, Fluorescence, Sedimentation, Western Blot, Stable Transfection, Expressing, Fractionation