Fig. 1: ATR interacts with membranes and preserves nuclear morphology.

a Images from routine 60 nm EM section with enrichment of nano-gold-labeled ATR in the perinuclear region. Colored arrowheads indicate actin-associated (black), chromatin-associated (red), and membrane-associated ATR (yellow), respectively (scale bar 500 ηm for the right and 200 ηm for the left panel). b Defective nuclear morphology of ATR-depleted HeLa cells visualized with immunofluorescence of Lamin B1 (NE) and DAPI (DNA) (scale bar = 50 μm). c Quantification of nuclear deformations by manual sorting based on their degree of deformation: Normal, mildly deformed and severely deformed (n = 515, 525, 229 cells for shCtrl, shATR1, and ShATR2, respectively). Quantifications of d micronuclei (n = 515, 525, and 229 cells for shCtrl, shATR1, and ShATR2, respectively) and e nuclear circularity index (n = 288, 253, and 215 cells for shCtrl, shATR1, and ShATR2, respectively; N = 3 independent experiments). f EM images of the nucleus from control and ATR-depleted HeLa cells. Arrowheads indicate invaginations with nucleoli attachment (scale bar 5 μm). Bar graphs presented as mean ± SEM and box plot whiskers and outliers plotted with Tukey’s method. p-values calculated using two-way ANOVA test for c or for d. e Ordinary one-way ANOVA test with Dunnett’s multiple comparisons test (****P < 0.0001, ***P < 0.001, **P < 0.01, *P < 0.05; NS, not significant). Source Data file contains source data and all additional details of statistical analysis.