Fig 1: PP1a-Cavin3 complex in UV-induced DNA damage response. a PLA interaction between Cavin3 and PP1a upon UV treatment. DAPI detects the nucleus (blue). b Quantification of PLA Cavin3/PP1a interactions in control and UV-treated cells as the mean ± SD, three individual experiments. ****p-value (Student’s t-test, two tail) < 0.0001. c The number and ratio of nuclear (Nuc.; purple) and cytoplasmic (Cyto.; gray) localized PLA signals for Cavin3-PP1a interactions presented as mean ± SD, three independent experiments in a histogram and table. d Quantitation of caveolae number in untreated and UV-treated A431 cells. Caveolae number on the apical surface from four sets of images were quantified blinded from three independent experiments and were normalized to the length of the surface sampled (over 150 µm for each set of images where **p = 0.0027, Student’s t-test, two tail). e A431 cells transfected with scrambled siRNA (control), Cavin3 and PP1a individually or together were exposed to UV treatment. Lysates were western blotted for ?H2AX and H2AX anti-PP1a and anti-Cavin3 and a-Tubulin antibodies. f Relative protein expression (%) of ?H2AX (Scrambled vs siCavin3: *p = 0.0172, Scrambled vs siPP1: ****p < 0.0001), Cavin3 (Scrambled vs siCavin3: ****p < 0.0001, Scrambled vs siCavin3+siPP1: ****p < 0.0001), and PP1a (Scrambled vs siPP1: ****p < 0.0001, Scrambled vs siCavin3+siPP1: ****p < 0.0001), three independent experiments, one-way ANOVA with a Tukey’s multiple comparison test. g Western blot analysis of cleaved PARP, cleaved-caspase-3, total caspase-3 and GAPDH in PP1a- or/and Cavin3-knockdown A431 cells. h Relative protein expression (%) of cleaved PARP (Scrambled vs siCavin3: *p = 0.0486, Scrambled vs siPP1: ****p<0.0001), cleaved caspase-3 (Scrambled vs siCavin3: *p = 0.0465, Scrambled vs siPP1: ***p = 0.0001) and total caspase-3 (Scrambled vs siCavin3: *p = 0.0109, Scrambled vs siPP1: ****p < 0.0001). Three independent experiments analyzed using one-way ANOVA. i LDH release (% of total LDH) was calculated (Scrambled vs siPP1: ****p < 0.0001, Scrambled vs siCavin3: *p = 0.0243). Significance was determined by one-way ANOVA and a Bonferroni test from three independent experiments